MIRO Experiment User Manual
RO-MIR-PR-0030 Issue 7.0 31 August 2018
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
MIRO Experiment User Manual
Prepared by:
Margaret Frerking Samuel Gulkis Mark Hofstadter Lucas Kamp Timothy Koch Robert Nowicki
F.Peter Schloerb
Approved by
Mark Hofstadter Date
MIRO Principal Investigator
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Table of Contents
LIST OF TABLES ......................................................................................................................................x
LIST OF FIGURES ...................................................................................................................................xi
CHANGE LOG.........................................................................................................................................xii
1 OVERVIEW....................................................................................................................................1-1
1.1 SCIENTIFIC OBJECTIVES .......................................................................................................1-1
1.1.1 Introduction...........................................................................................................1-1
1.1.2 Science Objectives and Investigation....................................................................1-2
1.1.3 Measurement Approach........................................................................................1-5
1.1.4 MIRO Science Data Deliverables.........................................................................1-5
1.2 HARDWARE DESCRIPTION....................................................................................................1-6
1.2.1 Introduction...........................................................................................................1-6
1.2.1.1 Performance Characteristics................................................................1-6
1.2.1.2 System Overall Configuration.............................................................1-6
1.2.2 Detailed Description.............................................................................................1-9
1.2.2.1 Telescope.............................................................................................1-9
1.2.2.2 Calibration Targets............................................................................1-10
1.2.2.3 Millimeter-Wave Heterodyne Receiver.............................................1-11
1.2.2.4 Submillimeter-Wave Heterodyne Receiver.......................................1-11 1.2.2.5 Spectrometer Assembly.....................................................................1-14 1.2.2.6 Flight Computer.................................................................................1-15
1.2.2.7 Command and Data Handling System...............................................1-15
1.2.2.8 Power Handling and Distribution......................................................1-16
1.3 SOFTWARE DESCRIPTION ...................................................................................................1-16
1.3.1 Flight Software Development Environment........................................................1-16
1.4 OPERATIONAL MODES .......................................................................................................1-16
2 EXPERIMENT CONFIGURATION............................................................................................2-1
2.1 PHYSICAL UNITS ..................................................................................................................2-1
2.2 CALIBRATION SWITCH MECHANISM ....................................................................................2-4 2.3 ELECTRICAL .........................................................................................................................2-5
2.3.1 Power Interface.....................................................................................................2-5
2.3.1.1 General Interface Description..............................................................2-5
2.3.1.2 Power Distribution Block Diagram and Redundancy..........................2-6 2.4 SOFTWARE............................................................................................................................2-7
2.4.1 Overview...............................................................................................................2-7 2.4.2 Commanding.........................................................................................................2-7
2.4.3 Hardware Interfaces...........................................................................................2-10
2.4.4 Spectral Data Interface.......................................................................................2-10
2.4.4.1 CTS Control.......................................................................................2-10
2.4.4.2 PLL, LO, and IFP Control.................................................................2-12
2.4.5 Continuum Data Interface ..................................................................................2-12
2.4.6 Engineering Data Interface ................................................................................2-13
2.4.7 Power Interfaces.................................................................................................2-14
2.4.8 Mirror Control Interface.....................................................................................2-15
2.4.9 Pin-Puller Control..............................................................................................2-15
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2.4.10 Inbound FIFO Interface......................................................................................2-16
2.4.11 Outbound FIFO Interface...................................................................................2-16
2.4.12 Interrupts Interface.............................................................................................2-16
2.5 BUDGETS (MASS, POWER, DATA RATES)...........................................................................2-17
2.5.1 Mass....................................................................................................................2-17 2.5.2 Operating Power.................................................................................................2-17
2.5.3 Data Rate Overview............................................................................................2-19
2.5.4 Data Rates Within Modes ...................................................................................2-20
2.6 NON-OPERATING HEATERS................................................................................................2-30
2.7 SPACECRAFT POWERED THERMISTORS..............................................................................2-30
2.8 PYRO LINES ........................................................................................................................2-30 2.9 OBDH CHANNEL................................................................................................................2-30
2.9.1 Channel Allocation .............................................................................................2-30 2.9.2 Telemetry.............................................................................................................2-30 2.9.3 Telecommand......................................................................................................2-30
2.9.4 Bit Rate Requirements.........................................................................................2-31 2.9.5 Timing.................................................................................................................2-31 2.9.6 Monitoring..........................................................................................................2-31
2.9.6.1 Telecommands and Verification........................................................2-31
2.9.6.2 Experiment Status and Event Reporting............................................2-31
2.9.7 Electrical Interfaces Circuits..............................................................................2-31
2.9.7.1 General ..............................................................................................2-31 2.9.7.2 Telemetry...........................................................................................2-32 2.9.7.3 Telecommand ....................................................................................2-33
2.9.7.4 Broadcast Pulse (TSY) ......................................................................2-34
2.9.7.5 Environmental and Status Monitoring...............................................2-35 2.9.7.6 Redundancy.......................................................................................2-35
2.9.8 On-board Operational Interface with DMS........................................................2-35
2.9.8.1 Telecommand ....................................................................................2-35 2.9.8.2 Telemetry...........................................................................................2-35
EXPERIMENT OPERATIONS ....................................................................................................3-1
3.1 OPERATING PRINCIPLES .......................................................................................................3-1
3.1.1 Instrument Power On, Warmup, and Stabilization...............................................3-1 3.1.2 Functional Tests....................................................................................................3-1
3.1.3 In-Flight Calibration Observations......................................................................3-1
3.1.3.1 Radiometric .........................................................................................3-3 3.1.3.2 Frequency............................................................................................3-3
3.1.3.3 Field of View.......................................................................................3-3
3.1.4 Primary Scientific Observations...........................................................................3-3
3.1.4.1 Asteroid Mode.....................................................................................3-3
3.1.5 MIRO Flight Computer Memory Operations........................................................3-4
3.1.6 Thermal Operating Limits.....................................................................................3-4
3.1.7 Optimizing Data Taking........................................................................................3-4
3.1.7.1 Calibration Heater................................................................................3-4
3.1.7.2 CTS Gap..............................................................................................3-5
3.1.7.3 Housekeeping Cycle Skip....................................................................3-5 3.2 OPERATING MODES..............................................................................................................3-5
3.2.1 Ground Test Plan..................................................................................................3-5
3.2.2 In-orbit Commissioning Plan (MIRO EID-B, 6.3.2.2)........................................3-6
3.2.3 Instrument Checkout.............................................................................................3-6
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3.2.4 Flight Operations Plans (MIRO EID-B, 6.3.2.3)................................................3-6
3.2.4.1 Launch Phase.......................................................................................3-7 3.2.4.2 Cruise Phases.......................................................................................3-7
3.2.4.3 Mars Gravity Assist.............................................................................3-7
3.2.4.4 Earth Gravity Assists...........................................................................3-7 3.2.4.5 Steins Fly-by........................................................................................3-7
3.2.4.6 Lutetia Fly-by......................................................................................3-7
3.2.4.7 Deep Space Hibernation Mode (DSHM).............................................3-7
3.2.4.8 Rendezvous Manoeuvre ......................................................................3-7
3.2.4.9 Comet Drift Phase ...............................................................................3-7
3.2.4.10 Comet Approach Navigation and Maneuvering..................................3-8
3.2.4.11 Nucleus Mapping and Close Observation...........................................3-8
3.2.4.12 SSP Delivery and Comet Escort to Perihelion ....................................3-8
3.2.5 Interferences .........................................................................................................3-8
3.2.6 Operational Constraints .......................................................................................3-8
3.3 FAILURE DETECTION AND RECOVERY STRATEGY ...............................................................3-9
4 MODE DESCRIPTIONS ...............................................................................................................4-1
4.1 MODE TRANSITION TABLE ...................................................................................................4-1
4.2 DETAIL MODE DESCRIPTION ................................................................................................4-2
4.2.1 Engineering Mode.................................................................................................4-2
4.2.2 Millimeter Continuum Mode.................................................................................4-3
4.2.3 SubmillimeterContinuum Mode...........................................................................4-3
4.2.4 Dual Continuum Mode..........................................................................................4-3
4.2.5 CTS / Submillimeter Continuum Mode .................................................................4-3
4.2.6 CTS / Dual Continuum Mode................................................................................4-4 4.2.7 Asteroid Mode.......................................................................................................4-4
4.2.7.1 LO Settings in Asteroid Mode.............................................................4-5
5 CONTINGENCY RECOVERY AND FLIGHT CONTROL PROCEDURES/SEQUENCES5-1
6 DATA OPERATIONS HANDBOOK (TELECOMMANDS).....................................................6-1
6.1 TELECOMMANDS ..................................................................................................................6-1
6.1.1 Warm Up Telecommands......................................................................................6-1
6.1.1.1 Calibration Heater Telecommand........................................................6-1
6.1.1.2 USO Power Telecommand..................................................................6-3
6.1.1.3 CTSWarm UpTelecommand.............................................................6-6
6.1.2 Mode Change Telecommands.............................................................................6-10
6.1.2.1 Mode Change Telecommand.............................................................6-10
6.1.2.2 AsteroidMode Telecommand...........................................................6-17
6.1.3 Additional Engineering Mode Telecommands....................................................6-23
6.1.3.1 Engineering Housekeeping Cycle Skip Telecommand .....................6-23
6.1.4 Additional Continuum Mode Telecommands......................................................6-26
6.1.4.1 Continuum Subtraction Value Telecommand ...................................6-26
6.1.4.2 Millimeter LNA Power Telecommand..............................................6-28
6.1.4.3 Submillimeter LNA Power Telecommand Definition.......................6-30
6.1.5 Additional Spectroscopic Mode Telecommands .................................................6-33
6.1.5.1 IFP PowerControl Telecommand.....................................................6-33
6.1.5.2 SubmillimeterGunn VoltageTelecommand.....................................6-36
6.1.5.3 PLL Reset Telecommand ..................................................................6-40
6.1.5.4 SMM Gunn Voltage Auto-control Enable/Disable Telecommand....6-43
6.1.5.5 CTSHeaterControl Telecommand...................................................6-45
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6.1.5.6 CTS Internal Calibration Telecommand............................................6-48
6.1.5.7 CTSDataMasksTelecommand........................................................6-53
6.1.5.8 CTS Run Time Telecommand...........................................................6-58
6.1.5.9 CTS Pulse Position Telecommand ....................................................6-62
6.1.6 Calibration Mirror Control Telecommands .......................................................6-65
6.1.6.1 Move Mirror Telecommand ..............................................................6-65
6.1.6.2 Step Mirror Telecommand.................................................................6-67
6.1.7 Software Telecommands .....................................................................................6-71
6.1.7.1 Software Restart Telecommand.........................................................6-71
6.1.7.2 Memory Checksum Telecommand....................................................6-73
6.1.7.3 Memory Dump Telecommand...........................................................6-75
6.1.7.4 Memory Load Telecommand ............................................................6-78
6.1.8 S/C Interface Telecommands ..............................................................................6-81
6.1.8.1 Enable MIRO HK Generation Telecommand ...................................6-81
6.1.8.2 DisableMIRO HK GenerationTelecommand..................................6-82
6.1.8.3 Time Update Telecommand ..............................................................6-84
6.1.8.4 Connection Test Telecommand.........................................................6-86
6.1.8.5 Enable Science Telecommand...........................................................6-88
6.1.8.6 Disable Science Telecommand..........................................................6-89
6.1.8.7 Reset Telemetry Telecommand.........................................................6-91
DATA OPERATIONS HANDBOOK (TELEMETRY)..............................................................7-1
7.1 TELEMETRY..........................................................................................................................7-1
7.1.1 Introduction...........................................................................................................7-1
7.1.2
Housekeeping Data Telemetry..............................................................................7-2
7.1.2.1 Description ..........................................................................................7-2
7.1.2.2 Packet Definition.................................................................................7-2
7.1.2.3 Expected Values..................................................................................7-7 7.1.2.4 Calibration.........................................................................................7-31 7.1.2.5 Limits.................................................................................................7-34
7.1.2.6 RSDB Entries ....................................................................................7-36
7.1.3 Spectroscopic (CTS) Science Telemetry..............................................................7-37
7.1.3.1 Description ........................................................................................7-37
7.1.3.2 Packet Definition...............................................................................7-38
7.1.3.3 Expected Values................................................................................7-39 7.1.3.4 Calibration.........................................................................................7-41
7.1.3.5 RSDB Entries ....................................................................................7-42
7.1.4 Submillimeter ContinuumScience Telemetry.....................................................7-42
7.1.4.1 Description ........................................................................................7-42
7.1.4.2 Packet Telemetry Definition..............................................................7-43 7.1.4.3 Expected Value..................................................................................7-44 7.1.4.4 Calibration.........................................................................................7-45
7.1.4.5 RSDB Entries ....................................................................................7-45
7.1.5 Millimeter Continuum Science Telemetry...........................................................7-46
7.1.5.1 Description ........................................................................................7-46
7.1.5.2 Packet Telemetry Definition..............................................................7-46
7.1.5.3 Expected Values................................................................................7-47 7.1.5.4 Calibration.........................................................................................7-48
7.1.5.5 RSDB Entries ....................................................................................7-48
7.1.6 Miscellaneous Science Telemetry .......................................................................7-48
7.1.6.1 Description ........................................................................................7-48
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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7.1.6.2 Packet Definition...............................................................................7-49 7.1.6.3 Expected Value..................................................................................7-51
7.1.6.4 RSDB Entries ....................................................................................7-51
7.1.7 Memory Dump Telemetry....................................................................................7-51
7.1.7.1 Description ........................................................................................7-51
7.1.7.2 Packet Definition...............................................................................7-52 7.1.7.3 Expected Value..................................................................................7-53
7.1.7.4 RSDB Entries ....................................................................................7-53
7.1.8 Memory Checksum Telemetry.............................................................................7-54
7.1.8.1 Description ........................................................................................7-54
7.1.8.2 Packet Definition...............................................................................7-54 7.1.8.3 Expected Value..................................................................................7-55
7.1.8.4 RSDB Entries ....................................................................................7-56
7.1.9 MIRO On (Progress Event Report #1) Telemetry...............................................7-56
7.1.9.1 Description ........................................................................................7-56
7.1.9.2 Packet Definition...............................................................................7-57 7.1.9.3 Expected Value..................................................................................7-58
7.1.9.4 RSDB Entries ....................................................................................7-58
7.1.10 Asteroid Mode Started (Progress Event Report #2) Telemetry...........................7-58
7.1.10.1 Description ........................................................................................7-58
7.1.10.2 Packet Definition...............................................................................7-59 7.1.10.3 Expected Value..................................................................................7-60
7.1.10.4 RSDB Entries ....................................................................................7-60
7.1.11 Asteroid Mode Completed (Progress Event Report #3) Telemetry.....................7-60
7.1.11.1 Description ........................................................................................7-60
7.1.11.2 Packet Definition...............................................................................7-61 7.1.11.3 Expected Value..................................................................................7-62
7.1.11.4 RSDB Entries ....................................................................................7-62
7.1.12 Connection Report Telemetry .............................................................................7-62
7.1.12.1 Description ........................................................................................7-62
7.1.12.2 Telemetry Definition.........................................................................7-63 7.1.12.3 Expected Value..................................................................................7-63
7.1.12.4 RSDB Entries ....................................................................................7-64
7.1.13 Mirror Error Report Type 1 Telemetry...............................................................7-64
7.1.13.1 Description ........................................................................................7-64
7.1.13.2 Packet Definition...............................................................................7-65
7.1.13.3 Expected Values................................................................................7-66
7.1.13.4 RSDB Entries ....................................................................................7-66
7.1.14 Mirror Error Report Type 2 Telemetry...............................................................7-66
7.1.14.1 Description ........................................................................................7-66
7.1.14.2 Packet Definition...............................................................................7-67 7.1.14.3 Expected Value..................................................................................7-68
7.1.14.4 RSDB Entries ....................................................................................7-68
7.1.15 Mirror Error Report Type 3 Telemetry...............................................................7-68
7.1.15.1 Description ........................................................................................7-68
7.1.15.2 Packet Definition...............................................................................7-69 7.1.15.3 Expected Value..................................................................................7-70
7.1.15.4 RSDB Entries ....................................................................................7-70
7.1.16 Mirror Error Report Type 4 Telemetry...............................................................7-70
7.1.16.1 Description ........................................................................................7-70
7.1.16.2 Packet Definition...............................................................................7-71
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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7.1.16.3 Expected Value..................................................................................7-72
7.1.16.4 RSDB Entries ....................................................................................7-72
7.1.17 Mirror Error Report Type 5 Telemetry...............................................................7-72
7.1.17.1 Description ........................................................................................7-72
7.1.17.2 Packet Definition...............................................................................7-73 7.1.17.3 Expected Value..................................................................................7-74
7.1.17.4 RSDB Entries ....................................................................................7-74
7.1.18 CTS Error Report Telemetry...............................................................................7-74
7.1.18.1 Description ........................................................................................7-74
7.1.18.2 Packet Definition...............................................................................7-75 7.1.18.3 Expected Value..................................................................................7-76
7.1.18.4 RSDB Entries ....................................................................................7-76
7.1.19 Accept Success Event Report Telemetry .............................................................7-76
7.1.19.1 Description ........................................................................................7-76
7.1.19.2 Packet Definition...............................................................................7-77 7.1.19.3 Expected Value..................................................................................7-78
7.1.19.4 RSDB Entries ....................................................................................7-78
7.1.20 Incomplete Packet Event ReportTelemetry........................................................7-78
7.1.20.1 Description ........................................................................................7-78
7.1.20.2 Packet Definition...............................................................................7-79
7.1.20.3 Expected values.................................................................................7-80
7.1.20.4 RSDB Entries ....................................................................................7-80
7.1.21 Incorrect Checksum Event Report Telemetry .....................................................7-80
7.1.21.1 Description ........................................................................................7-80
7.1.21.2 Packet Definition...............................................................................7-81
7.1.21.3 Expected Values................................................................................7-82
7.1.21.4 RSDB Entries ....................................................................................7-82
7.1.22 Incorrect APID Event Report Telemetry.............................................................7-82
7.1.22.1 Description ........................................................................................7-82
7.1.22.2 Packet Definition...............................................................................7-83
7.1.22.3 Expected Values................................................................................7-84
7.1.22.4 RSDB Entries ....................................................................................7-84
7.1.23 Invalid Command Code Event Report Telemetry Definition ..............................7-84
7.1.23.1 Description ........................................................................................7-84
7.1.23.2 Packet Definition...............................................................................7-85 7.1.23.3 Expected Value..................................................................................7-86 7.1.23.4 RSDB Inputs......................................................................................7-86
7.1.24 Additional Rosetta Telemetry Relevant to MIRO................................................7-86
8 USE OF THE EQM AFTER LAUNCH........................................................................................8-1
8.1 SUMMARY ............................................................................................................................8-1 8.2 REQUIREMENTS ....................................................................................................................8-1
8.3 REQUIREMENTS FOR ESAMANPOWER ................................................................................8-1
9 SCIENCE DATA.............................................................................................................................9-1
9.1 INTRODUCTION.....................................................................................................................9-1
9.2 ANTENNA TEMPERATURE ....................................................................................................9-1
9.2.1 Definition of Antenna Temperature ......................................................................9-1
9.2.2 Antenna Temperature of MIRO Calibration Targets............................................9-2
9.2.3 Antenna Temperature of a Source of Emission.....................................................9-4
9.2.4 Relationship of Antenna Temperature to Physical Temperature..........................9-5
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9.3 SPECTROMETER BAND LOCATIONS......................................................................................9-7
9.3.1 Introduction...........................................................................................................9-7
9.3.2 Bands Defined by IF Filters..................................................................................9-7
9.3.3 Bands Defined for PerformanceMonitoring........................................................9-9
9.3.4 Bands Defined for On-Board Data Compression...............................................9-10
9.4 MAPPING SKY FREQUENCY TO SPECTROMETER CHANNEL NUMBER ................................9-11
9.4.1 Introduction.........................................................................................................9-11
9.4.2 Algorithms to Convert RF Frequency Bands to the IFP Output Frequencies....9-12
9.4.3 Algorithms to Convert CTS Channel Numberinto IFInput Frequency.............9-14
9.4.4 Algorithm to Convert CTS Input Frequency to RF Frequency...........................9-15
9.5 MIRO CALIBRATION ..........................................................................................................9-16
9.5.1 Introduction.........................................................................................................9-16
9.5.2 Radiometric Calibration Summary.....................................................................9-16
9.5.3 A Monograph On MIRO Calibration..................................................................9-19
9.6 MIRO BORESIGHT AND GEOMETRY DATA PRODUCTS......................................................9-19
9.6.1 MIRO Boresight..................................................................................................9-19
9.6.2 MIRO Geometry Data Products .........................................................................9-21
9.7 ERROR BARS ON MIRO CALIBRATED SCIENCE DATA.......................................................9-25
9.7.1 Introduction.........................................................................................................9-25 9.7.2 Continuum Data..................................................................................................9-25
9.7.3 Spectrometer Data..............................................................................................9-26
9.8 FREQUENCY SWITCHING AND "FOLDED" SPECTRA.........................................................9-31
9.9 BEAM PATTERNS, SPILLOVER, AND ANTENNA TEMPERATURES...............................................9-32
APPENDICES
A MIRO Calibration
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List of Tables
Table 1.1-1: The MIRO submillimeter receiver is fixed tuned to observe simultaneously the eight
molecular transitions shown in this table.........................................................................1-2 Table 1.1-2: Relationship to Stated Goals of Rosetta Mission.............................................................1-4 Table 1.2-1: MIRO Instrument Performance Characteristics...............................................................1-7 Table 1.2-2: IF Frequencies for the Submillimeter-wave Receiver. Mixer numbers refer to numbers
given in Figure 1.2-5......................................................................................................1-13 Table 2.3-1: Power Supply Interface....................................................................................................2-5 Table 2.5-1: Measured Mass of the MIRO Instrument in Kilograms ................................................2-17 Table 2.5-2: MIRO Power Consumption by Mode............................................................................2-18 Table 2.5-3: Comments on the Power Options Shown in Table 2.5-2...............................................2-19 Table 2.5-4: Default Data Rates Including Overhead........................................................................2-20 Table 2.5-5: Engineering Mode..........................................................................................................2-21 Table 2.5-6: MM Continuum Mode...................................................................................................2-21 Table 2.5-7: SMM Continuum Mode.................................................................................................2-21 Table 2.5-8: Dual Continuum Mode ..................................................................................................2-22 Table 2.5-9: CTS/ SMM Continuum Mode .......................................................................................2-23 Table 2.5-10: CTS Dual Continuum Mode..........................................................................................2-26 Table 2.5-11: Asteroid Mode...............................................................................................................2-29 Table 2.9-1: Experiment OBDH Interface Channels/Functions.........................................................2-30 Table 3.1-1: MIRO Calibration/Observing Needs ...............................................................................3-2 Table 3.1-2: Calibration Priorities (1 = highest) ..................................................................................3-3 Table 3.3-1: MIRO Failure Modes and Possible Recovery Operations.............................................3-10 Table 4.1-1: Mode Transition Table.....................................................................................................4-2 Table 4.2-1: Initial LO Setting for Specific Molecules........................................................................4-5 Table 9.2-1: Representative Differences between Physical and Antenna Temperatures....................9-6 Table 9.3-1: Band Boundaries Defined by the IFP Narrow-Band Filters............................................9-8 Table 9.3-2: Performance Monitoring Bands.....................................................................................9-10 Table 9.3-3: On-Board Data Compression Bands..............................................................................9-10 Table 9.4-1: The Eight Molecular Transitions Observed by MIRO...................................................9-12 Table 9.4-2: Frequency Oscillators Internal to MIRO .......................................................................9-12 Table 9.4-3: RF (Sky Frequencies) Targeted by MIRO.....................................................................9-13 Table 9.4-4: RF (Sky Frequencies) to IF Frequency..........................................................................9-14 Table 9.4-5: Parameters Relating CTS Channel to Frequency...........................................................9-15 Table 9.4-6: Band boundaries, RF and IF Center Frequencies, and Direction Factor for Conversion
Between the IF and RF Frequency.................................................................................9-15 Table 9.5-1: Allocation of Time in a Calibration Sequence...............................................................9-16 Table 9.7-1: One-sigma Uncertainty of MIRO Calibrated Continuum Data .....................................9-24
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
List of Figures
Figure 1.2-1: MIRO Instrument Block Diagram ...................................................................................1-8
Figure 1.2-2: Isometric Drawing of the MIRO optical bench. ..............................................................1-9
Figure 1.2-3: Schematic Diagram of the Millimeter-wave Receiver Front End..................................1-11
Figure 1.2-4: Schematic Diagram of the Submillimeter-wave Receiver Front End............................1-12
Figure 1.2-5: Schematic Diagram of the Submillimeter-wave Receiver Intermediate Frequency
Processor........................................................................................................................1-13
Figure 1.2-6: Chirp Transform Spectrometer Configuration...............................................................1-15
Figure 2.1-1: Electronics Unit ...............................................................................................................2-1
Figure 2.1-2: Sensor Unit ......................................................................................................................2-2
Figure 2.1-3: Sensor Backend Electronics Unit.....................................................................................2-3
Figure 2.1-4: Ultra Stable Oscillator .....................................................................................................2-3
Figure 2.2-1: Calibration Switch Mechanism........................................................................................2-5
Figure 2.3-1: Power Distribution Block Diagram (Electronics Unit)....................................................2-6
Figure 2.3-2: Power Distribution Block Diagram (Sensor Backend Electronics Unit)........................2-7
Figure 2.4-1: MIRO Software Data Flow and Control Diagram...........................................................2-9
Figure 2.4-2: MIRO Hardware Data and Control Flow.......................................................................2-11
Figure 2.9-1: Telemetry Interface Circuit-Data Output and Sample Input .......................................2-32
Figure 2.9-2: Telecommand Interface Circuit-Data Input, Clock Input (combined with TM) and
Sample Input ..................................................................................................................2-33
Figure 2.9-3: Broadcast Pulse (TSY) Circuit Interface .......................................................................2-34
Figure 6.1-1: Angles associated with Calibration mirror positions .....................................................6-67
Figure 7.1-1: T1 Spectrometer (one of four thermistors-T1, T2, T3, T4-on the CTS acoustic delay
line section)....................................................................................................................7-10
Figure 7.1-2: T6 Spectrometer (one of two thermistors-T5, T6-on the CTS electronics section). The
temperature in this section of the CTS follows the EU temperature..............................7-10
Figure 9.3-1: IFP narrow-band filter transmission functions and representative spectral lines.............9-8
Figure 9.4-1: The basic elements of the smm heterodyne receiver system. ........................................9-11
Figure 9.6-1: Apparent offset of the comet nucleus from its expected location in 91 raster maps made
by MIRO during 2015....................................................................................................9-20
Figure 9.9-1: Millimeter (left) and submillimeter (right) beam patterns ........................................9-33
Figure 9.9-2: Azimuthally averaged millimeter (top) and submillimeter (bottom) beam patterns....................9-35
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Change Log
Version Date Revised By Description
4.4 3/30/2009 Removed requirement to turn off MIRO during thruster firings (Sections 3.2.5 and 3.2.6)
4.4 3/30/2009 Removed the PMRG entries under "Parameters" and moved the PMRD entries up to replace it in the following subsections: 6.1.1.3.5 (ZMR19221)6.1.2.1.5 (ZMR 19214)6.1.4.1.5 (ZMR19218)6.1.5.5.5 (ZMR19215)6.1.5.7.5 (ZMR19217)6.1.5.8.5 (ZMR19210)6.1.6.2.5 (ZMR19222)6.1.8.1.5 (ZMR00301)
4.5 Draft 8/10/2009 Tables 2.5.4-1 through 2.5.4-6 have been changed to reflect a new housekeeping rate. Internal Release Only.
4.5 2/25/2011 Add Chapter 9 and general reformatting
4.6 3/29/2011 Add Sections 9.3 and 9.4, reformatting, update data compression and packet length information in Chapter 6 to reflect software patches.
5.0 9/25/2013 General reformatting to a smaller file size; minor word-smithing; changes to Section 2.5.2, 4.2.5, 4.2.7, 6.1.2.1.1, and 6.1.5.9.4.3
5.1 3/26/2014 Update Table 2.5-2: MIRO Power Consumption by Mode Update Notes following Table 2.5.2 Update Table 2.5-4: Default Data Rates Including Overhead
6.0 8/31/2017 MDH Correct typos and add clarifications in various sections. Add Sections 9.5, 9.6, and 9.7.
6.1 1/31/2018 MDH Several minor text clarifications and typos.
6.2 5/31/2018 MDH Add description of Level 3 Version 3 data products
(primarily Sections 9.3.5 and 9.5.2), various minor updates to other
sections.
6.3 5/31/2018 MDH Add Section 9.8, correct various typos.
6.4 6/15/2018 MDH Clarifications to Fig. 1.2-4 and Section 9.5.2
(regarding background subtraction). Corrections to Sections 4.2.7.1,
7.1.3.3, 7.1.3.4 (regarding LO settings), Section 9.8 (Folding of
spectra), and Table 9.4-6 (line frequencies). Other typos corrected in
various sections.
7.0 8/313/2018 MDH Add section 9.9 and update 9.7. Corrections and clarifications in 9.4, 9.7, 9.8.
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OVERVIEW
1.1 SCIENTIFIC OBJECTIVES
1.1.1 INTRODUCTION
The investigation, Microwave Instrument for the Rosetta Orbiter (MIRO), addresses the nature of the cometary nucleus, outgassing from the nucleus and development of the coma as strongly interrelated aspects of cometary physics, and searches for outgassing activity on asteroids. MIRO is configured both as a continuum and a very high spectral resolution line receiver. Center-band operating frequencies are near 188 GHz (1.6 mm) and 562 GHz (0.5 mm). Spatial resolution of the instrument at 562 GHz is approximately 5 m at a distance of 2 km from the nucleus; spectral resolution is sufficient to observe individual, thermally broadened, line shapes at all temperatures down to 10 K or less. Four key volatile species-H2O, CO, CH3OH, and NH3-and the isotopes-H217O and H218O-are pre-programmed for observation. These lines are listed in Table 1.1-1. The primary retrieved products are abundance, velocity, and temperature of each species, along with their spatial and temporal variability. This information will be used to infer coma structure and processes, including the nature of the nucleus/coma interface.
MIRO will sense the subsurface temperature of the nucleus to depths of several centimeters or more using the continuum channels at millimeter and submillimeter wavelengths. Model studies will relate these measurements to electrical and thermal properties of the nucleus and address issues connected to the sublimation of ices, ice and dust mantle thickness, and the formation of gas and dust jets. The global nature of these measurements will allow in situ lander data to be extrapolated globally, while the long duration of the mission will allow us to follow the time variability of surface temperatures and gas production. Models of the thermal emission from comets are very crude at this time since they are only loosely constrained by data. MIRO will offer the first opportunity to gather subsurface temperature data that can be used to test thermal models. MIRO is highly complementary to the IR mapping instrument on the orbiter, having similar spatial resolution but greater depth penetration.
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Table 1.1-1: The MIRO submillimeter receiver is fixed tuned to observe simultaneously the eight molecular transitions shown in this table.
Species Frequency (MHz) Transition
Water H216O H217O H218O 556936.002 552020.960 547676.440 1(1,0)-1(0,1) 1(1,0)-1(0,1) 1(1,0)-1(0,1)
Carbon Monoxide CO 576267.9305 J(5-4)
Ammonia NH3 572498.3784 J(1-0)
Methanol CH3OH CH3OH CH3OH 553146.296 568566.054 579151.005 8 (1)--7 (0) E 3 (-2)--2 (-1) E 12 (-1)--11(-1) E
1.1.2 SCIENCE OBJECTIVES AND INVESTIGATION
The measurement objectives of the MIRO investigation are listed below.
1. Characterize abundances of key volatile species and isotope ratios
The MIRO instrument will measure absolute abundances of key volatile species- H2O, CO, CH3OH, and NH3-and quantify fundamental isotope ratios-17O/16O and 18O/16O -in a region within several km from the surface of the nucleus, nearly independent of the orbiter to comet nucleus distance.
Water and carbon monoxide are chosen for observation because they are believed to be the primary ices driving cometary activity. Methanol is a common organic molecule, chosen because it is a convenient probe of gas excitation temperature by virtue of its many transitions. Knowledge of ammonia abundance has important implications for the excitation state of nitrogen in the solar nebula. By providing measurements of isotopic species abundances with extremely high mass discrimination, the MIRO experiment can use isotope ratios as a discriminator of cometary origins. The MIRO investigation will combine measurements of the variation of outgassing rates with heliocentric distance with models of gas volatilization and transport in the nucleus to quantify the intrinsic abundances of volatiles within the nucleus.
2. Understand processes controlling outgassing in upper surface layers of the nucleus
The MIRO experiment will measure surface outgassing rates for H2O, CO, and other volatile species, as well as nucleus subsurface temperatures to study key processes controlling the outgassing of the comet nucleus. Correlated measurements of outgassing rates and nucleus thermal properties will be used to test models of gas formation, transport, and escape from the nucleus to advance our understanding of the important processes leading to nucleus devolatilization.
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3. Study the processes controlling the development of the inner coma
MIRO will measure density, temperature, and kinematic velocity in the transition region close to the surface of the nucleus. Measurements of gas density, temperature, and flow field in the coma near the surface of the nucleus will be used to test models of the important radiative and dynamical processes in the inner coma, and thus improve our understanding of the causes of observed gas and dust structures. The high spectral and spatial resolution provided by the MIRO instrument will provide a unique capability to observe narrow Doppler-broadened spectral lines resulting from the low gas temperatures and low pressures. Asymmetric lines shapes due to Doppler shifts of the evaporating and effusing gases in the line of sight to the comet nucleus will be searched for to understand the boundary layer at the nucleus.
4. Characterize the nucleus subsurface to depths of few centimeters or more
The MIRO instrument will map the nucleus and determine the subsurface temperature distribution to depths of several centimeters or more. Morphological features on scales as small as 5 m will be identified and correlated with regions of outgassing. The combination of global outgassing and temperature observations from MIRO and in situ measurements from the Rosetta lander will provide important insights into the origins of outgassing regions and of the thermal inertia of subsurface materials in the nucleus.
5. Search for low levels of gas in the asteroid environment
The MIRO instrument will measure subsurface temperatures and search for low levels of water vapor (and other constituent gases) in the vicinity of asteroids (2867) Steins and (21) Lutetia to provide information on near surface thermal characteristics including the presence or absence of a regolith or water ice.
6. Search for high altitude water vapor in the atmosphere of Mars
The MIRO instrument has the potential for providing unique data about the upper atmosphere of Mars during the Rosetta encounter with the planet in February 2007. No other instrument with the capabilities of MIRO has been on a spacecraft in the vicinity of Mars. Its very high-resolution spectrometer makes it sensitive for measuring high altitude water concentration and winds. Its two continuum channels will provide surface and sub-surface temperatures. Carbon monoxide and several isotopes of water can also be measured or upper limits set.
The relationships between MIRO objectives and those identified in ESA SCI(93)7 are given in Table 1.1-2.
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Table 1.1-2: Relationship to Stated Goals of Rosetta Mission
To Achieve Rosetta Objectives MIRO Will Corresponding MIROObjectives
Global characterization of nucleus, surface morphology and composition, and dynamic properties * Perform global temperature mapping (maximum ground resolution <5m) * Dayside and nightside * Derive thermo-physical properties of subsurface * Detect and characterize active/inactive regions using temperature and spectroscopic detection of H2O, CO, and NH3 * Confirm state of rotation Globally characterize the nucleus subsurface to depths of a few centimeters or more
Chemical, mineralogical, and isotopic composition of volatiles and refractories in cometary nucleus * Measure abundances and isotopic ratios of important coma gases (H2O, NH3, CO, CH3OH) Characterize the abundances of major volatile species and key isotope ratios in volatiles
Physical properties and interrelation of volatiles and refractories in cometary nucleus * Measure gas temperature and molecular excitation (CH3OH) in near surface coma * Measure flow velocities Study the processes controlling the development of the inner coma Study the processes controlling outgassing in the surface layer of nucleus
Study of development of cometary activity and the processes in the surface layer of the nucleus and in the inner coma * Measure onset outgassing of water and carbon dioxide * Measure local origin of outgassing * Measure gas flow velocities Study the processes controlling the development of the inner coma Study the processes controlling outgassing in the surface layer of nucleus
Origin of comets, relationship * Measure oxygen isotopes to Study the processes
between cometary and infer temperature of formation controlling outgassing in the
interstellar material, and origin * Measure outgassing as function surface of the nucleus
of Solar System of heliospheric distance Characterize the abundances of major volatile species and key isotopes ratios in volatiles
Global characteristics of * Measure temperature Search for low levels of gas in
asteroids, dynamic properties, * Search for low levels of the asteroid environment
surface morphology, and outgassing
composition * Confirm state of rotation
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1.1.3 MEASUREMENT APPROACH
The MIRO experiment will acquire both high-resolution molecular line spectra in absorption and emission, and broadband continuum emission data from which gas abundances, velocities, temperatures, and nucleus surface and subsurface temperatures will be derived.
The MIRO instrument is composed of a millimeter wave mixer receiver operating with a center-band frequency of 188 GHz, and a submillimeter heterodyne receiver operating with a center-band frequency of 562 GHz. The two receivers are fixed tuned. The submillimeter wave receiver provides both broad-band continuum and high-resolution spectroscopic data, whereas the millimeter wave receiver provides continuum data only.
The submillimeter wave spectroscopic frequencies allow simultaneous observations of six molecules, chosen to achieve four (1, 2, 3, and 5) of the five MIRO objectives. The six molecules pre-selected are known constituents of comets. The submillimeter wave lines observed include the ground-state rotational transition of water 1(10)-1(01) at 557 GHz, the corresponding lines of two oxygen isotopes of water, and the 572 GHz ground state rotational line of ammonia J(1-0). Since these lines are ground-state transitions (i.e., between the lowest rotational levels of these molecules), they are expected to be the strongest in cometary conditions. The submillimeter spectrometer can also observe the CO J(5-4) line, and three methanol lines.
The millimeter and submillimeter wavelength continuum channels address the MIRO objective number 4. Using the continuum channels, MIRO will sense the subsurface temperature of the nucleus to depths of several centimeters or more. Model studies will relate these measurements to electrical and thermal properties of the nucleus and address issues connected to the sublimation of ices, ice and dust mantle thickness, and the formation of gas and dust jets.
1.1.4 MIRO SCIENCE DATA DELIVERABLES
1.
Intensity Calibrated Continuum Data at 188 GHz;
2.
Intensity Calibrated Continuum Data at 562 GHz;
3.
Intensity and Frequency Calibrated Spectral Line Data at 562 GHz;
4.
Average brightness temperatures of two asteroids at two frequencies;
5.
Brightness temperature (partial) maps of comet nucleus at two frequencies;
6.
Brightness temperature versus solar phase observations of the comet nucleus at two frequencies;
7.
Calculated abundances for all observed molecules as a function of time and spatial position;
8.
Measured Doppler velocities for all observed molecules as function of time and spatial position; and
9.
Calculated temperature of the coma from methanol spectral line data.
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1.2 HARDWARE DESCRIPTION
1.2.1 INTRODUCTION
The MIRO instrument provides both very sensitive continuum capability for temperature determination and very high-resolution spectroscopy for observation of molecular species. The instrument consists of two heterodyne radiometers, one at millimeter wavelengths (1.3 mm) and one at submillimeter wavelengths
(0.5 mm). The millimeter and the submillimeter radiometers have continuum bandwidths of 0.5 GHz and 1.0 GHz, respectively. The high-resolution submillimeter spectrometer has a total bandwidth of 180 MHz and a spectral resolution of 44 kHz (4096 channels). Eight different RF frequency bands are shifted into contiguous frequency bands to feed the 180-MHz spectrometer. This allows simultaneous observations of 8 molecular transitions that span a frequency range of 31.5 GHz.
1.2.1.1 Performance Characteristics
Key MIRO instrument performance characteristics are summarized in Table 1.2-1.
1.2.1.2 System Overall Configuration
A block diagram of the MIRO instrument is shown in Fig. 1.2-1. An isometric drawing of the MIRO optical bench is shown in Figure 1.2-2. The instrument is packaged into four separate units. A description of each unit is provided below.
1.
The Sensor Unit consists of the telescope, baseplate, and optical bench. The Sensor Unit is mounted to the spacecraft skin at the baseplate. The telescope, mounted on the baseplate, is outside the spacecraft, while the optical bench, also mounted to the baseplate, is inside the spacecraft. The optical bench carries the millimeter-and submillimeter-wave receiver front ends (RFEs), the calibration mechanism, and the quasi-optics for coupling the telescope to the RFEs.
The opening in the Optical Bench Plate under the Turning Mirror is where light from the telescope first enters the optical bench. The Turning Mirror directs the incoming light to the Diplexer. The wire grid Diplexer splits the light from the telescope into a mm component and a smm component. The mm component passes through the Diplexer and is directed with the mm Matching mirror to the mm receiver front end (RFE) mixer shown on the left of the figure. The smm component is reflected from the Diplexer toward the smm Matching Mirror which directs the signal to the smm receiver front end (RFE) mixer shown on the left.
2.
The Sensor Backend Electronics Unit is flush mounted internal to the spacecraft on a louvered radiator. It contains the intermediate frequency processor, the phase lock loop, frequency sources and power conditioning and housekeeping electronics.
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3.
The Electronics Unit is flush mounted internal to the spacecraft on a louvered radiator. It contains the Chirp Transform Spectrometer (CTS), the instrument computer, and the power conditioning circuits.
4.
The Ultra-Stable Oscillator (USO) Unit is flush mounted internal to the spacecraft and provides the high accuracy frequency reference for the instrument.
Table 1.2-1: MIRO Instrument Performance Characteristics
Equipment Property Millimeter-Wave Submillimeter-Wave
Telescope Primary Diameter Primary F/D Edge taper on primary Near Sidelobe level Angular Resolution Primary surface accuracy Fraction power in main beam Polarization 30 cm 1 > 20 dB <-30 dB 23.8 +/- arcmin <12 microns ~ 93% s/c x-axis 30 cm 1 >20db <-30 dB 7.5+/-0.25 arcmin < 12 microns ~93% s/c y-axis
Spectral RF Frequency Band 186.7-189.7 GHz 547.6-579.2 GHz
Performance IF Bandwidth 1-1.5 GHz 5.5-16.5 GHz
Spectral Resolution N/A 44 kHz
Allocated Spectral Range per line N/A ~ 20 MHz
Accuracy < 1 MHz 10 kHz
Spectrometer Center Frequency/Bandwidth Number of channels 1350/180 MHz 4096
Radiometric Performance DSB Receiver Noise Temperature SSB Spectroscopic Sensitivity (300 KHz, 2 min) 2000 K ~4000 K
relative 2 Krms
absolute Continuum Sensitivity (1 sec): 3 Krms
relative 1 Krms 1 Krms
absolute 3 Krms 3 Krms
Data Rates Continuum Mode Spectroscopic Mode On-board Storage <1 kbps 2 kbps 0.2 Gb (one day's data volume, Mode 3, 100% duty cycle, see Table 2.5-7)
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1.2.2 DETAILED DESCRIPTION
1.2.2.1 Telescope
The parabolic primary mirror has a diameter of 30 cm, providing a diffraction-limited half-power main beamwidth of about 7.5 arc min at 560 GHz frequency
(0.535 mm wavelength) and about 23.8 arc min at 188 GHz (1.6 mm wavelength). An offset Cassegrain design is used to minimize volume and provide very low-level sidelobes. The end-to-end optical system is designed to minimize alignment sensitivity to the large temperature range the telescope will experience during the course of the mission. The Cassegrain design also reduces or eliminates multiple reflections between the receiver input and the secondary mirror, which is a major problem with on-axis systems.
Sets of beam wave-guiding mirrors bring the signals to the feed horns at the receiver front ends (RFEs) on the optical bench, with a minimum amount of loss. The illumination of the primary mirror by millimeter and submillimeter receivers is a Gaussian pattern with >20 dB edge taper resulting in <30 dB sidelobe levels for the primary beam patterns.
A significant advantage of the offset Cassegrain design is the absence of aperture blockage and the resulting improvement in both aperture and beam efficiency. The efficiency of the telescope is also a function of the mirror surface accuracy. The surface RMS is 11 um corresponding to less than ./48 at 0.535 mm. Combining the effects of the illumination, surface error, and reflectivity losses, the telescope has an aperture efficiency of greater than 0.7 and a main beam efficiency of greater than 0.93 at both frequencies.
The telescope is designed to operate at temperatures between ~100 K at comet rendezvous to temperatures near ~300 K at perihelion. To maximise performance
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over this large temperature range, the telescope is fabricated entirely of aluminium so that it scales with temperature to maintain a sharp focus. The beam is nearly parallel at the telescope/optical bench interface minimising misalignment along the optical path. Lateral misalignments are minimized by symmetrical design in one axis and fixing the telescope mount near the beam axis through the baseplate.
1.2.2.2 Calibration Targets
Radiometric calibration of the instrument is accomplished using two calibration targets at different temperatures. A permanent-magnet stepper motor switches the RF input to the mm and smm receivers from the telescope to either a cold calibration target or a warm calibration target to provide measurements of the receiver gains. The switching is accomplished by positioning a small mirror in the optical path of the instrument to one of three positions (sky, hot load, cold load). In normal operation, the gain is calibrated every 30 minutes by switching between hot load, cold load and telescope (sky) positions. Gain calibration is completed in 2 minutes, allowing 28 minutes out of every 30 minutes for observations.
A fail-safe device (pin puller) has been built into the mirror actuator mechanism. In case of a mirror actuator failure, the switching mirror can be moved out of the optical path through the use of a built-in pin puller. In this position, the RF inputs to the receivers arrive from the telescope. A "pulled" pin can be reinserted into the drive mechanism if the failure can be resolved.
The two calibration targets are mounted on the MIRO instrument itself, and each is at a different physical temperature by virtue of its location. The colder of the two targets is mounted outside the spacecraft, exposed to space. It comes to radiative equilibrium under the influence of sunlight, the spacecraft exterior, the MIRO telescope, cold space, and nearby objects such as the comet itself. The second target (warm) is mounted inside the spacecraft close to the optical bench. The warm calibration target contains an on-off heater that can be used to increase its temperature above the optical bench temperature. Neither target is temperature controlled, however redundant thermistor sensors provide accurate measurements of the target temperatures.
The calibration targets are constructed from aluminium, machined on one side to form a series of regularly spaced pyramids. The pyramids are coated with an absorber coating material to provide an emissivity greater than 0.99 in both the mm and smm bands.
During spectroscopic observations, the submillimeter wave receiver is operated in a "frequency switched" mode to eliminate residual baseline ripple. For half the integration time, the signal frequency is shifted 5 MHz above the nominal frequency, while the other half of the time it will be shifted 5 MHz below. The frequency is switched every 5 seconds. The on-board computer subtracts the spectra obtained during alternating switch cycles and reports the difference. In normal operation, the difference spectra contains data from three full switch cycles, corresponding to 30 seconds of data. (Interleaving the frequency settings
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for total integrations longer than 10 seconds helps compensate for systematic drifts during the integration period.)
1.2.2.3 Millimeter-Wave Heterodyne Receiver
The millimeter-wave receiver is a total power, single channel, continuum radiometer. Its operating wavelength is near 1.6-mm. A block diagram of the system is shown in Figure 1.2-3.
The 1.6-mm wave signal is down converted by mixing with a local oscillator (LO) signal at half its frequency in the subharmonic mixer. The resulting intermediate frequency (IF) is filtered and then detected for the total power continuum channel in the Intermediate Frequency Processor (IFP).
1.2.2.4 Submillimeter-Wave Heterodyne Receiver
The submillimeter-wave receiver operates both as a single broadband radiometer for continuum measurements, and as a spectroscopic receiver. The receiver is fixed tuned to observe three isotopes of water, (H216O, H217O and H218O), three methanol lines (CH3OH), ammonia (NH3), and carbon monoxide (CO). A block diagram of the submillimeter wave RFE is shown in Figure 1.2-4. A block diagram of the Intermediate Frequency Processor (IFP) is shown in Figure 1.2-5 and Table 1.2-2 lists the observed lines along with the various frequencies associated with the IFP.
The 0.5-mm wave signal is down converted to a first IF band of 5.5 to 16.5 GHz. A divider separates out the continuum band while the spectroscopic signal is further down converted for input to the spectrometer. Table 1.2-2 summarizes the
down converted frequencies for each spectral line of the down converted spectrum for input into the spectrometer. The LOs are used multiple times to save power. Nominally 20 MHz wide filters are used in the IFP before input to the spectrometer to eliminate excess noise. The bandwidth of the spectral line receiver will allow observations over Doppler shifts of +/- 5.4 km/sec or +/- 8 km/sec with frequency switching. This will allow short spectral observations of the asteroids near closest approach, and measurements of low velocity molecular clouds.
Table 1.2-2: IF Frequencies for the Submillimeter-wave Receiver.Mixer numbers refer to numbers given in Figure 1.2-5
IF 1 IF 2 IF 3 IF 4 IF 5 IF 6 IF 7 IF 8 IF 9 Output to CTS
Lines RF (MHz) M1 out M2 out M3 out M4 out M5 out M6 out M7 out M3 out
( ) 2x2182 7728 7728 7147 2182 7147 2x2182 7728
H218O 547677 15136 - - - - 7989 5807 1340 - 1340
H217O 552021 10792 6428 - - 1300 - - - - 1300
CH3OH 553146 9667 14031 6303 1425 - - - - - 1425
H216O 556936 5877 - - - 1270 - - - - 1270
CH3OH 568566 5753 1389 - - - - - - - 1389
NH3 572498 9685 14049 6321 1407 - - - - - 1407
CO 576268 13455 9091 1363 - - - - - - 1363
CH3OH 579151 16338 - - - 9191 - 2044 6408 1320 1320
1.2.2.5 Spectrometer Assembly
The spectrometer is connected to the output of the Intermediate Frequency Processor (IFP) which down converts only the parts of the submillimeter-wave receiver's first IF that are necessary. The spectrometer's function is to perform real-time spectral analysis of the down converted submillimeter-wave signals. The spectrometer output is a digitized power spectrum supplied to the Command and Data Handling System.
The spectrometer is a Chirp Transform Spectrometer having 4096 channels, each channel having a resolution of 44 kHz. The high spectral resolution is needed to observe thermally broadened spectral lines in the comet coma.
Figure 1.2-6 shows the configuration used for the MIRO experiment. In the expander unit a chirp is generated by impulsing a reflective array compressor (RAC) filter with 450-MHz center frequency, 180-MHz bandwidth, and 20-microsecond dispersion time. The amplified chirp is dispersed by a second RAC of the same type, again amplified and finally frequency doubled. The output signal of the expander unit is a chirp centered around 900 MHz with 360-MHz bandwidth and 40-microsecond dispersion time. The sync delay between the two expander subunits is about 20 microseconds. The compressor unit has an input frequency of 1350 MHz with a bandwidth of 180 MHz (the input bandwidth of the CTS). The input signal is multiplied by the expander output signal. The resulting 450-MHz difference frequency signal is filtered by another RAC of the same type as used in the expander unit, since a chirp slope inversion took place due to mixing into the lower sideband. The output of the compressor subunit is combined in a commutator, and split into real and imaginary parts. Subsequently the baseband signal is digitized by two eight-bit analog-to-digital converters. Within a 20-microsecond interval, 4096 digitized channels are distributed into an acquisition memory. The next spectrum is available after the next transform interval and added channelwise to the former one. The memory read out interval is programmable between about 1 s and 5 s.
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1.2.2.6 Flight Computer
The flight computer for MIRO is a radiation hardened Reduced Instruction Set Computer (RISC) System/6000 (also referred to as RS/6000) which was used on the Mars Pathfinder and Mars Surveyor Projects. The design of this computer is based on the Rios Single Chip (RSC) RISC microprocessor with implementation of the VMEbus and RS232 interfaces and it provides up to 128 Mbytes of local memory (RAM). The processor is a single chip implementation of the IBM Model 220 workstation and it is considered to be in the POWER PC architecture family. In the MIRO application, the RS/6000 computer is operated at a divided down clock speed of 2.5 MHz to reduce power. This was accomplished by replacing the normal 40-MHz oscillator in the MIRO RS/6000 with a 20-MHz oscillator
1.2.2.7 Command and Data Handling System
The Command and Data Handling (C&DH) system consists of all the electronics that control the operation of the instrument and communicates to the spacecraft via a serial port. The C&DH consists of the computer, flight software, engineering data electronics (EDE), and power supply. The computer receives, processes, verifies, and executes all commands that control the operation of the instrument via the flight software. The C&DH directs the acquisition of science and housekeeping telemetry and formats the data in the appropriate packets. The EDE monitors selected temperature, voltage, and current levels within the instrument.
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1.2.2.8 Power Handling and Distribution
The 28-Vdc input from the spacecraft is converted into the various voltages needed by the instrument and distributed to the assemblies in the Electronics Unit and separately in the Sensor Back End Unit.
1.3 SOFTWARE DESCRIPTION
The onboard MIRO flight software controls the MIRO Instrument hardware. The software consists of a start-up routine followed by a generic executive. The executive activates Command and Data Handler, Data Collection and Transfer, Sequencing, Calibration, and Background Processor and these modules execute the appropriate routines for each required function.
The science data including calibration measurements are packetized and stored in a standard format. Housekeeping data including instrument health data (temperatures, currents, and voltages), mode of operation and science data are stored and reported in the telemetry packets (CCSDS format as described in the ESA Telemetry Standard).
A more complete description of the MIRO software can be found in Section 2.4.
1.3.1 FLIGHT SOFTWARE DEVELOPMENT ENVIRONMENT
The WindRiver Tornado VxWorks kernel system for the RS/6000 was used for flight software development. The VxWorks Real-Time Operating System includes multitasking preemptive priority scheduling, intertask synchronization and communications facility, interrupt handling support, and memory management. The host machine for the flight software development was a Sun Ultra-10 Workstation, running UNIX (Solaris OS v2.5.1).
1.4 OPERATIONAL MODES
MIRO is configured to have seven primary operational modes. Each mode provides a different capability, and has a different power consumption (see Section 6 for a detailed description of each mode). The engineering mode (1 mode) provides a low power mode to obtain housekeeping measurements only. Single and dual receiver continuum modes (3 modes) are available to obtain the radiometric brightness within the MIRO field-of-view from the millimeter and submillimeter channels. These modes are useful for the investigation of the properties of surfaces such as those of the asteroids and comet nucleus. There are two spectroscopic modes (2 modes). One provides both smm and mm continuum (CTS/dual continuum) as well as the smm spectroscopic channels. The second provides the smm continuum channel, and the smm spectroscopic channels (CTS/smm). These spectroscopic modes allow a sensitive detection of specific gases generated by the comet nucleus (and possibly the asteroids as well). A single mode, called the asteroid mode (1 mode), is designed for the two asteroid encounters. In this mode, the receiver is configured in the CTS/dual continuum mode. The data rate and setting of the first local oscillator are modified for the asteroid mode.
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In the comet rendezvous stage of the mission, it is envisaged that MIRO will initially be turned on in a continuum mode to detect and measure the continuum emission from the nucleus. During the cometary and targeted mapping phases, a majority of the viewing will be in the one or two receiver/spectrometer modes to study outgassing processes, bulk composition, and coma formation. These phases will provide the highest spatial resolution for studying the nucleus. If limb sounding is feasible, it would enhance the minimum detectability of species, and allow greater resolution of the coma.
Following the mapping phase, MIRO plans to operate in the CTS/ dual continuum mode. During this phase, both nucleus and coma studies will be performed.
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EXPERIMENT CONFIGURATION
2.1 PHYSICAL UNITS
MIRO consists of four distinct physical units and an interconnecting harness. The electronics unit configuration is shown in Figure 2.1-1, the sensor unit configuration is shown in Figure 2.1-2, the sensor backend electronics unit is shown in Figure 2.1-3, and the ultra stable oscillator is shown in Fig. 2.1-4.
The electronics unit consists of four assemblies bolted together into a single unit. The four assemblies include the spectrometer analog assembly, the spectrometer digital assembly, the data handling assembly and the command and power assembly. The electronics unit attaches to the spacecraft payload panel by 8 M5 screws. It is mechanically separated from the sensor backend electronics unit and can be up to two meters in distance away from it.
The sensor unit includes the following three major assemblies: telescope, baseplate, and the optical bench. It is mounted on the Rosetta payload (+Z) panel using the baseplate. The baseplate is a 405x250x25 mm machined aluminium panel with structural ribs with a total thickness of 25 mm. It is accommodated by top-mounting over a slighter smaller cut-out in the spacecraft payload panel. It is attached to the spacecraft payload panel by 10 M5 screws, making it thermally coupled to the payload panel, and hence collectively controlled. A 50 mm hole through the baseplate allows the RF signal from the telescope to pass through the baseplate to the optical bench.
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Figure 2.1-2: Sensor Unit
The telescope, consisting of a primary reflector, a secondary reflector and interconnecting structure, is constructed entirely from aluminium. It is attached to the outside of the baseplate by a thin-wall epoxy-glass cylinder, making it thermally isolated from the spacecraft. Also attached to the outside of the baseplate is the calibration cold target, which is isolated from the baseplate by a thin-wall cynate ester cylinder.
The optical bench is attached to the baseplate side that is internal to the spacecraft. The attachment is through a kinematic mount making it thermally isolated from the baseplate. A radiator is mounted to the optical bench to remove the power dissipated on the bench. It attaches to the bench with eight M4 screws and is detachable during installation of the sensor unit. The calibration hot target is also attached to the baseplate internal to the spacecraft. Mounted on the optical bench are all the elements requiring optical alignment-the mirrors, calibration switch, polarization splitting diplexer, millimeter-wave receiver front-end and submillimeter-wave receiver front-end.
The sensor backend electronics unit consists of three assemblies bolted together: the power and housekeeping assembly, the intermediate frequency processor assembly and the phase lock loop assembly. It also has three frequency
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synthesizer assemblies mounted to the exterior surface of the phase lock loop assembly. The sensor backend electronics unit attaches to the spacecraft payload panel by 6 M5 screws.
The ultra-stable oscillator unit is attached to the spacecraft payload panel by 4 M 4 screws. It is mechanically separate from but connected by harness to the sensor unit and the electronics unit. The ultra-stable oscillator can be up to two meters away from the sensor unit and up to two meters away from the electronics unit.
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2.2 CALIBRATION SWITCH MECHANISM
The only mechanism in the instrument is the calibration switch mechanism that switches the input to the front-ends from the telescope to either the cold calibration target or the hot calibration target. The configuration is shown in Figure 2.2-1. The actuator is a permanent-magnet stepper motor with a planetary geartrain. It is stepped at 27 pulses per second to drive the mirror at 0.27 degrees per second. Positive mirror positioning is determined by means of LED-photodiode pairs for each of the three positions. Soft and hard stops at the ends of travel, combined with the counter weighting, preclude a launch latch. The permanent magnet provides passive holding of position with the power off. A failsafe device insures that the mirror can be positioned in the telescope position to receive science data if the actuator fails. The fail-safe is a thermally controlled shape memory metal pinpuller coupling between the actuator and the mirror. If needed, current is supplied to the pinpuller, retracting a retention pin. A spring returns the mirror to the telescope position. The mirror and the pinpuller are individually counter weighted to reduce torque to the motor during ground testing and launch.
The mechanism has been fully tested functionally and environmentally, and a qualification model has been life-tested to a number of cycles which exceed the requirement specified in EID-A 2.2.6.3 (4 times ground operational cycles plus 2 times orbit predicted cycles). All design features are previously used in flight experiments, or have gone through extensive testing for existing space programs.
Most of the mechanism is aluminium structure with Vespel bushings. However, the motor, geartrain, fail-safe device and sensors contain a variety of materials. Of interest to the spacecraft are the magnets and lubricant of the actuator. Similar stepper motors have been characterized and found to be well within the spacecraft magnetic field requirement, even without shielding. The motor lubricant is a highly refined low vapour pressure oil, which has been used inside sensitive optical instruments. The shape memory metal alloy used in the pinpuller device was originally developed for the Wide Field Planetary Camera II Project and has gone through extensive breadboard testing.
By virtue of the counterweight to make ground testing of the mechanism possible, the low duty cycle to prevent overheating, the optical bench cover for protection and the small inertia/low speed of the moving mass, the mechanism is not expected to offer any constraints on the spacecraft.
The mechanism operates approximately 1/2 minute each thirty minutes during observations. For an eighteen-month escort mission, this is 0.3 months of operation.
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2.3 ELECTRICAL
2.3.1 POWER INTERFACE
2.3.1.1 General Interface Description
The spacecraft power subsystem provides to MIRO:
*
Electrical power from a voltage regulated DC main bus.
*
Protected distribution and switching of power.
Table 2.3-1: Power Supply Interface
Function Number of Main Lines Number of Redundant Lines LCL Class
+28 V Main Bus MIRO Experiment Supply (Switched and Current Limited) 1 1 E (109 W / 4.0 A trip-off limit)
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2.3.1.2 Power Distribution Block Diagram and Redundancy
The power routing within MIRO is shown in Figure 2.3-1. The 28 V Main and Redundant lines supply the power to the MIRO's Electronics Unit. The selected 28 V power line is filtered and sent to the Sensor Backend Electronics Unit, and the secondary supplies of the Electronics Unit. Secondary power to the Chirp Transform Spectrometer (CTS) and the Ultra Stable Oscillator (USO) is switched by control of MIRO's computer.
Figure 2.3-2 shows how the secondary power is switched by MIRO's computer for the Millimeter and Submillimeter receivers for the various operating modes.
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2.4 SOFTWARE
2.4.1 OVERVIEW
The MIRO software architecture is designed to be compliant with the ESA EID-A while at the same time also fulfilling the science functional requirements. The EID-A primarily defines the MIRO software interface to the spacecraft. The Flight Software Requirement Document, RO-MIR-RS-0005 provides a complete description of the MIRO flight software originally delivered to ESA and executed in the FM. Subsequent patches to the software are not contained in this document.
The primary data and control flows are shown in Figure 2.4-1. A collection of chirp transform spectrometer (CTS) data, millimeter continuum data, and submillimeter continuum data constitute the primary task of the MIRO software. The MIRO software architecture has been designed to maximize the collected amount of science data over time. Many different operating sub-modes have been defined to reduce the amount of data returned, to allow for operation during mission phases when other Rosetta instruments are competing for downlink bandwidth. The collected science data is then packetized as per the EID-A TM definition and transferred to the Rosetta spacecraft.
2.4.2 COMMANDING
There is no internal sequence machine resident within the MIRO flight software. It is simply command driven, and takes limited action on its own. All commands will be issued to the MIRO software via either on board control procedures
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(OBCPs) executed by the Rosetta spacecraft computer or as nominal mission timeline (MTL) commands. OBCPs are used where closed loop control is required over the MIRO software by the spacecraft computer. Closed loop control is where the DMS would monitor telemetry generated by the MIRO software and alter the commands being sent based on that telemetry. The nominal MTL commands are used for open loop commanding where the spacecraft issues MIRO a command and does not perform any processing of MIRO generated telemetry. Most of the MIRO commanding will be via the MTL. Exceptions to this will include startup and shutdown OBCPs.
The MIRO OBCPs and nominal MTL commands will be uplinked to the spacecraft as required to support operations during the various phases of the mission. The MIRO S/W will not be altering the contents of its eeprom resident data. Most operating parameters will be given default values that can be overridden by uplinked telecommand. It is envisioned that during the course of the mission, a small list of parameter changes, software patches, etc. will be sent to the MIRO software each time it is restarted via the startup OBCP. The software design has been structured to support this operations concept. Any MIRO information that needs to be monitored and/or acted upon by the DMS will be defined in the EID-B.
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2.4.3 HARDWARE INTERFACES
The primary definitions of the interfaces between the MIRO software and the associated MIRO hardware are described in the individual MIRO hardware ICDs. This section will define the software interface to the hardware as viewed from a software development perspective. Most of the information contained in this section is the result of conversations with the various hardware PEMs. See Figure 2.4-2 for an overview of the MIRO hardware.
2.4.4 SPECTRAL DATA INTERFACE
2.4.4.1 CTS Control
The interface to the CTS is via a bi-directional port. It is a 32-bit interface, which is both read from and written to. Access to this interface is via the VME bus. The software that executes to read from or write to the CTS is simply a read or write from a specific memory address. The CTS is an intelligent hardware device that is programmed by the MIRO software to integrate for a specific period of time. MIRO is using a programmable duration (approximately 4.95 seconds) for all spectrometer scans. When the CTS has completed each scan, an interrupt is generated and sent to the MIRO software.
A signal called "busy" is generated by the CTS while it is performing each scan. In the case of an internal CTS error or an SEU event which disables the CTS, the busy line will remain high. The busy line remaining high after the CTS scan should have completed will be the triggering event for determining that the CTS has failed. It is not known whether the CTS will generate an interrupt or not during these 2 failure modes. Therefore only the busy line is being used as the failure indicator. SEU processing within the CTS is enabled by a special command sent to the CTS every time it is powered on. The nominal powering on sequence for the CTS will contain an "SEU Enable" command as the last action.
The CTS contains 4 internal sum of squares (SOS) tables which are 256*256 16-bit values. Prior to operation the SOS tables need to be loaded with data. The process of determining what values to load into the SOS tables prior to nominal data collection is called the CTS internal table calibration process. The table calibration of the SOS table requires about 45 seconds to complete. It will be recalculated each time the CTS is powered on, and also periodically during nominal operation via ground TC.
The MIRO software can also control the CTS internal heater temperature and power consumption. These are also implemented as a ground TC sent to the MIRO software, which is then sent to the CTS hardware.
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2.4.4.2 PLL, LO, and IFP Control
There is additional hardware that feeds the RF signal into the CTS after performing some pre-processing of the signal. The Sensor Unit Control Register (SUCR) is the means by which the other hardware is controlled.
There are 4 bits in the SUCR called IFP Power Control. These bits do not control power but control the gain of the RF data going into the CTS instrument. This is a very coarse control. The setting of these bits will be via a ground TC. Default values will exist in the software.
There is a bit in the SUCR for LO frequency control. This is used to switch the LO between the 2 possible settings. The LO is switched before each CTS scan is started, except when running is asteroid mode or raw data mode. There are 4 corresponding bits (phase lock alarms) in the Sensor Unit Status Register (SUSR) showing when the set frequencies have stabilized following an LO switch. See the hardware ICD for a description of whether a 0 or 1 indicates that the frequency output is not stable. The 4 alarms will need to be polled following the changing of the LO frequency to confirm that the new frequencies are locked in. The alarms will be polled during the scan at a 20 Hz rate, coinciding with continuum data collection. Any alarms that have changed will be reported back in the CTS telemetry.
When the CTS is not powered, the LO frequency cannot be controlled. The frequency changes will need to be skipped when running in a power configuration where the CTS is not turned on.
There is a bit in the SUCR called load_freq that gets set to load the 3 frequency synthesizer chips. A set of 3 fixed 19-bit values are then loaded by the FPGA hardware into the frequency synthesizers. The software will reload these every 30 minutes, before performing the instrument calibration. This should happen after the CTS is powered on and warmed up.
2.4.5 CONTINUUM DATA INTERFACE
The exact bit level definitions of all the registers discussed below can be found in the H/W ICDs. The following paragraph is supplied to familiarize the reader with the basic H/W involved in obtaining the data.
The I/F to the sensor backend electronics unit (SBEU) is via the 32-bit (SUCR). The software loads 16 bits at a time. All 32 bits are processed each time. The data from the SU is returned in the SUSR (64 bits). A software query initiates the data return. The contents of the SUSR include millimeter data (16 bits), submillimeter data (16 bits), SU and EU A/D data (12 bits) and various other data. Sensor unit A/D conversions require a small delay in order to return valid conversions. This delay is built into the software. The EU A/D conversions require no delay. A bit in the main control register (MCR) is used to set the millimeter and/or submillimeter sampling rate of 50 milliseconds. A 100-msec sampling rate is available in the hardware. However, the MIRO FSW is not designed to use this rate. When continuum data is ready, the H/W generates an interrupt that requires processing by the software.
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There are 3 sets of 4 bits used to control voltage or bias settings for the mm and smm receivers. These will be set to an optimum value prior to launch and the S/W will have the capability to change them in flight. This will be via ground TC.
2.4.6 ENGINEERING DATA INTERFACE
The I/F to the electronics unit (EU) consists of a 16 bit Electronics Unit Control Register (EUCR) and a corresponding 16 bit Electronics Unit Status Register (EUSR). The A/D data is collected from either the SUSR or EUSR depending on where the channel being sampled is located. The SU provides 32 channels of engineering data and the EU provides 24. All measurements are 12 bits. A bit in the MCR is then toggled to start the conversion running. The SUSR and EUSR each contain an end of conversion bit (EOC) indicating when a specific A/D conversion is complete. Polling of this bit would normally be required as there is no interrupt associated with the EOC. For the FM delivery the software will include built in delays to allow the conversions time to complete. The qqq milliseconds of delay that occur during the conversion process have no impact on the running code as the conversions are 200 milliseconds apart and the previous conversion completes before the next one is started.
The FM approach for performing an A/D conversion is as follows (assuming SU channel):
1.
Write the S/U channel number to the SUCR mux.
2.
Clock it out to the H/W.
3.
Write channel number 0 into the EUCR mux.
4.
Clock it out to the H/W.
5.
Delay 16-32 milliseconds.
6.
Toggle the start S/U convert bit in the MCR.
7.
Toggle the start E/U convert bit in the MCR.
8.
Wait 16-32 milliseconds to allow the conversions to complete.
9.
Set the SU status retrieve bit in the MCR.
10.
Wait 16-32 milliseconds.
11.
Read the converted S/U value out of the SUSR.
It should be noted that the S/U and E/U engineering conversion routines contain dummy conversions for the opposite interface. This addition was made because S/U conversions cause power fluctuations due to sharing a common power supply with other electronics. These power fluctuations alter the continuum data enough to be detected by ground processing software. The "skip engineering cycles" TC was added to allow for even further reductions of this noise.
2.4.7 POWER INTERFACES
The MIRO software has access to a total of 14 separate power switches. Some of these switches turn on and off multiple components. In some cases (i.e., CTS), multiple switches are required to turn on a single component.
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The first eight of these are via bits in the SUCR. The other 6 are via bits in the electronics mux register (EMUX).
1.
Millimeter continuum (multiple components), 2 switches
2.
Submillimeter continuum (multiple components), 2 switches
3.
Spectral data (multiple components), 2 switches
4.
Pin-Puller power
5.
Mirror motor power
6.
Ultra Stable Oscillator power
7.
CTS a. +5 Volts b. +3.3 Volts
c. +5 Volts analog d. +/-12 Volts
8.
Hot target power
The spectral data power is needed along with all the CTS power for any CTS operation. The spectral data power should be powered on after the CTS power. The USO is only needed for CTS operation, and it is automatically turned on every time the CTS is powered on. There is also a ground command to separately turn the USO on and off. The USO may be turned on well in advance of the CTS to allow for additional warm-up beyond what is required for just the CTS. HK telemetry packets will be generated during the warming up process so the warm up process can be monitored. The intent is to keep MIRO in the engineering mode until all the desired warm-up temperatures have been reached. The 3 sets of 4 voltage bias bits in the SUCR should be set prior to powering the associated (mm or smm) electronics on. The multiplier power is on all the time so that is not applicable to the setting of its 4 bits. A very short warm-up time is required for the mm and smm electronics. Data will be taken from these immediately after powering on.
Overall power control is via a combination of ground command and internal control. Mode switching will cause a pre-defined set of power control actions to occur prior to entering the new mode. Ground commands are used primarily to fine tune such things as IFP power control and SMM multiplier bias. No "sanity checking" will be performed by the onboard software with respect to processing the ground TCs. The ground operations personnel will be responsible for verifying that the commands sent to the instrument are correct and coherent.
There are 8 temperature set points and 3 power level settings within the CTS. One of the 3 power settings is an off setting. There will be a new control for "Pulse Position". This may need to vary based on the temperature level. The FM software will process the ground command for the pulse position to change the pulse position.
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2.4.8 MIRROR CONTROL INTERFACE
As part of the MIRO instrument calibration process, the viewing target is changed from space to a hot target followed by a cold target. Data is collected while pointing at each of these targets. There are 3 mirror positions: 1=space, 2=hot, 3=cold. The SUCR has 2 associated bits: mirror power control on/off and mirror direction forward/backward. There is another word where the number of mirror steps is loaded to cause the mirror to move. The mirror power bit should be set first prior to loading the step word, because loading the step word starts the countdown whether it is powered or not.
The mirror moves at 100 pulses per second and each pulse/step moves the mirror
0.27 degrees. Position 2 is 48.6 degrees from position 1, which is 180 steps requiring 1.44 seconds. Position 3 is 22.95 degrees from position 2, which is 85 steps requiring 0.68 seconds. There is a hard stop in both directions between positions 1 and 3. To go back to position 1 from position 3 requires changing the mirror direction to backward and going 180+85 steps = 265 total steps requiring
2.12 seconds.
The feedback to the S/W is 3 bits in the SUSR called mirror position. These will be set by the mirror electronics when the mirror is in the required position. All movements between 2 positions are accomplished via an initial gross movement followed by a series of single steps until the mirror position sensor indicates that the final position has been achieved.
All other data rate calculations in this document and appendices assume that the 3 mirror movements will require 5 seconds total time. The estimated movement time totals 4.24 seconds and the remainder allows for additional processing overhead.
2.4.9 PIN-PULLER CONTROL
There is a bit in the SUCR called the pin-puller bit. This activates the pin-puller mechanism. This is a fault recovery mechanism if the mirror is not responding as it should. Activation of the pin-puller will allow the mirror to move to position 1 automatically. The S/W will then move the motor enough steps, in reverse, to get back to position 1 from where ever it was. Backing up into the stop does not cause any wear and tear. At position 1, the pin-puller will automatically reinsert itself where it belongs. Mirror operation should be back to normal at this point. The S/W will generate an alarm if a pin pull is required and another confirming that it worked or didn't. An automated response has been built into the code to address cases where the use of the pin-puller mechanism is required. See fault protection section below.
2.4.10 INBOUND FIFO INTERFACE
The inbound FIFO is 512 words (1024 bytes). It is accessed by reading a 16-bit integer value from a memory location that is mapped, via vxworks, to the VME bus. There are status flags associated with the FIFO hardware that are accessible to the software. They are empty, half-full and full. The hardware keeps track of
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the read pointer. The software only needs to read from the required memory location to transfer data out of the FIFO. Polling of the status flags are required as the FIFO generates no interrupts to the software.
2.4.11 OUTBOUND FIFO INTERFACE
The outbound FIFO is sized to be 4096 words (8192 bytes). It is accessed by writing a 16-bit integer value to a memory location that is mapped, via vxworks, to the VME bus. There are flags associated with the FIFO hardware that are accessible to the software. They are empty, half-full, full, 1/4 full and 3/4 full. The hardware keeps track of the write pointer. The software only needs to write to the required memory location to transfer data into the FIFO. If the FIFO is read after being reset it will output a 16-bit word containing zero. The initial plan was to use this feature of the FIFO hardware to indicate to the S/C that we had no data to send. If the S/C reads a zero, it will indicate that we have no data to send. This proved to not be a robust enough design. See the description of the Outbound Fifo Manager Task for further details.
The software is able to transfer data into the FIFO over the VME bus about 4x faster than the spacecraft is capable of reading the FIFO. In spite of this, a race condition was detected during as mentioned above.
2.4.12 INTERRUPTS INTERFACE
The EU hardware handles all buffering of interrupts such that the software only needs to address the processing of 1 interrupt at a time.
There are only 3 interrupts that the FSW will receive:
1.
Time Synchronization
2.
CTS
3.
Continuum
Time Synchronization: This will occur every 8 seconds. If a new spacecraft TC packet has been received since the prior interrupt, the time value contained in the packet will be stored as our current spacecraft time.
CTS: This interrupt occurs when the spectrometer has finished collecting data for the programmed interval. This will be approximately every 5 seconds. Upon receipt of this interrupt the FSW will proceed to read the 16384 bytes of data out of the spectrometer. Since the readout requires 0.127 seconds, care must be taken so that other higher priority processing can interrupt this if required.
Continuum: The last interrupt that will be generated is for the continuum data. This interrupt will occur every 50 milliseconds. The FSW will need to read the collected data out and restart the continuum data collection.
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2.5 BUDGETS (MASS, POWER, DATA RATES)
2.5.1 MASS
The measured mass of the MIRO instrument, in kilograms, is provided in Table 2.5-1.
Table 2.5-1: Measured Mass of the MIRO Instrument in Kilograms
Unit Sub-unit Sub-unit mass (kg) Unit Mass (kg)
SU 6.7
Telescope 2.1
Baseplate 1.8
Optical Bench 2.8
SBEU 5.78
USO 1.12
EU 6.27
Wiring Harness 0.45
Total Mass 20.32
SU=Sensor Unit; SBEU=Sensor Backend Electronics Unit; USO = Ultra Stable Oscillator Unit; EU=Electronics Unit). This table does not include mass of multi-layer insulation (MLI).
2.5.2 OPERATING POWER
The MIRO instrument has six (6) primary power modes. Listed from lowest to highest power, they are (the numbering indicates the designation of each mode as reported in the "power" telmetered parameter):
6. Engineering Mode
5. Millimeter Continuum Mode (MMC)
4. Submillimeter Continuum Mode (SMMC)
3. Dual Continuum Mode (DualC)
2. Submillimeter Spectroscopic Mode (CTSSM)
1. Spectroscopic, dual continuum (CTSDC) In addition, Asteroid Mode is an operational mode whose power-level is
consistent with Mode #1, but which generates significantly more data (see Section 4.2.7).
Table 2.5-2 provides a detailed breakdown of power for the seven modes. Column 1 identifies the modes for each line in the table. Columns 2-5 show the power consumption for the calibration heater, the USO, the "Load" (described in the note below Table 2.5-2) operating power, and the CTS warmup, respectively. The submillimeter and millimeter Low Noise amplifiers power consumption are shown in Columns 6 and 7, respectively. Column 8 shows each mode's power consumption for normal operation (excepting Asteroid mode). The maximum and minimum power for each mode except for Asteroid mode are shown in columns 9
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and 10, respectively. The negative powers shown in columns 6 and 7 reflect the fact that the low noise amplifiers are normally turned on when the smm and mm receivers are turned on, however they can be powered off thereby reducing the power. Table 2.5-3 provides additional information about each option.
(Numbers are power in Watts)
Table 2.5-2: MIRO Power Consumption by Mode
MODE OPTIONS Normal Min Max
CalHtr USO Load CTS SMM MM
Min Max Warmup LNA LNA
Eng 0.7 2.5 9.2 4.1 20.6 N/A N/A 18.3 18.3 48.8
MMC 0.7 2.5 9.2 4.1 20.6 N/A 1.7 27.1 20.6 52.8
SMMC 0.7 2.5 9.2 4.1 20.6 -1.7 N/A 29.3 22.8 55.0
DualC 0.7 2.5 9.2 4.1 20.6 -1.7 -1.7 36.3 28.1 62.0
SMMS 0.7 Included - N/A -1.7 N/A 65.0 62.6 76.1*
CTSDC 0.7 Included - N/A -1.7 N/A 70.4 66.3 81.5*
Ast 0.7 Included - N/A N/A N/A Depends on playback mode
*CTS Max includes "CTS heating" power, which refers to a short-term activity in the CTS that occurs when it is turned on without a previous CTS Warmup. This can be affected by using the CTS Heater telecommand.
Load comes on automatically when USO or CalHtr is on and CTS (including CTS Warmup) is not on.
"Normal" implies: -CalHtr, USO and CTSWarmup off for Eng mode; -LNA and CalHtr on for Continuum, which therefore also has the Load on; -LNA and CalHtr on in CTS modes.
"Min" has all options off, including LNA. However, for CTS, USO is on in "Min" as this mode cannot be
usefully run without it. (For the CTS, "Min" also includes a drop of about 5.6W when the CTS is not integrating, which occurs for at most 0.5 second between the 5-second CTS scans.)
"Max" for Continuum modes adds the following to "Normal": USO(max) and CTS Warmup, but Load is off.
"Max" for CTS adds the following to "Normal": -6.7W for USO warmup (Max-Min), which takes about 0.4 hour. -4.4W for CTS heating, lasting about 1 hour; these numbers assume that the default temperature
and power level are used. If these are changed, using the CTS Heater telecommand, then the power and duration will also change.
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Table 2.5-3: Comments on the Power Options Shown in Table 2.5-2
Comments on Options In Table 2.5-2 Description
USO Powered on automatically when you enter any CTS mode; The USO can be powered on and off from all modes; Remains on when you move from mode to mode; The USO power is never turned off automatically; A command to power-off the USO off is required.
mmLNA Powered on automatically when the mm receiver is powered on; The only way to turn the LNA off (with mm on) is by direct command; Once turned off, the LNA stays off until 1) commanded on, 2) power off/on the instrument, or 3) a software restart is performed.
Smm LNA Powered on automatically when the smm receiver is powered on; The only way to turn the LNA off (with smm on) is by direct command; Once turned off, the LNA stays off until 1) commanded on, 2) power off/on the instrument, or 3) a software restart is performed.
CTS warmup The CTS warmup command is only issued from engineering, mm continuum, smm continuum, or dual continuum modes;
CTS heater This command is used only when the instrument is in a CTS mode This command sets the temperature regulation point of the SAW filters; internal clocks are not turned on until CTS mode is entered. There is a high and low power setting which determines the rate at which the filters are warmed; it is also possible to set the power to zero. The CTS heater is turned on automatically when you enter any CTS mode but the filter temperatures are set either by a global variable or by a previously set temperature.
2.5.3 DATA RATE OVERVIEW
The data rates for the MIRO instrument depend both on the instrument Mode, and on the integration time setting and the spectral resolution setting within an individual mode. The default settings correspond to the highest time resolution and highest spectral resolution for an individual mode. Table 2.5-4 gives the data rates for the default settings. The rates range from 103 bps in the engineering mode to 2517 bps in the CTS Dual Continuum mode. Data rates in the Asteroid mode do not exceed the maximum rate of 2517 bps. The total accumulated data volume, from launch through the near perihelion phase is estimated to be
9.213 Gbytes.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-4: Default Data Rates Including Overhead
Mode Name bps
Engineering 103
mm Continuum 460
smm Continuum 460
Dual Continuum 816
CTS/smm 2160
CTS/Dual Continuum 2517
Asteroid =2517
2.5.4 DATA RATES WITHIN MODES
Depending on the parameters specified in the mode change command, the MIRO software can generate a variety of telemetry data rates in the different power modes. Tables 2.5-5 through 2.5-11 give the data rates possible within each Mode. Nearly all MIRO telemetry packets have been designed to be 430 bytes in size. Collected telemetry data is then trickled out over time depending on the allowable data rate. The rate is specified as a fixed number (maximum) of 430 byte telemetry packets to be sent by the MIRO software to the spacecraft every 8 seconds.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-5: Engineering Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + 12.5% Packet Overhead (bps) Data Mode
1 0 0 N/A N/A 91 0 0 0 91 103 1
Table 2.5-6: MM Continuum Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 1 0 N/A N/A 91 344 0 0 435 460 1
1 2 0 N/A N/A 91 172 0 0 263 281 1
1 5 0 N/A N/A 91 69 0 0 160 174 1
1 10 0 N/A N/A 91 34 0 0 126 139 1
1 20 0 N/A N/A 91 17 0 0 109 121 1
Table 2.5-7: SMM Continuum Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 0 1 N/A N/A 91 0 344 0 435 460 1
1 0 2 N/A N/A 91 0 172 0 263 281 1
1 0 5 N/A N/A 91 0 69 0 160 174 1
1 0 10 N/A N/A 91 0 34 0 126 139 1
1 0 20 N/A N/A 91 0 17 0 109 121 1
2-21 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-8: Dual Continuum Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 1 1 N/A N/A 91 344 344 0 779 816 2
1 2 2 N/A N/A 91 172 172 0 435 460 1
1 5 5 N/A N/A 91 69 69 0 229 246 1
1 10 10 N/A N/A 91 34 34 0 160 174 1
1 20 20 N/A N/A 91 17 17 0 126 139 1
2-22 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-9: CTS/ SMM Continuum Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 0 1 32 1 91 0 344 1538 1639 2075 2160 6
1 0 1 32 2 91 0 344 775 901 1336 1394 4
1 0 1 32 3 91 0 344 513 646 1082 1130 3
1 0 1 32 4 91 0 344 385 522 957 1001 3
1 0 1 64 1 91 0 344 770 895 1330 1388 4
1 0 1 64 2 91 0 344 389 526 961 1005 3
1 0 1 64 3 91 0 344 257 398 834 873 3
1 0 1 64 4 91 0 344 193 336 772 808 2
1 0 1 96 1 91 0 344 514 647 1082 1131 3
1 0 1 96 2 91 0 344 260 401 836 875 3
1 0 1 96 3 91 0 344 172 316 751 787 2
1 0 1 96 4 91 0 344 129 274 710 744 2
1 0 1 128 1 91 0 344 386 523 958 1002 3
1 0 1 128 2 91 0 344 195 338 774 810 2
1 0 1 128 3 91 0 344 129 275 710 744 2
1 0 1 128 4 91 0 344 97 243 679 712 2
1 0 2 32 1 91 0 172 1538 1639 1903 1982 5
1 0 2 32 2 91 0 172 775 901 1164 1216 3
1 0 2 32 3 91 0 172 513 646 910 952 3
1 0 2 32 4 91 0 172 385 522 785 823 2
1 0 2 64 1 91 0 172 770 895 1158 1210 3
1 0 2 64 2 91 0 172 389 526 789 826 2
1 0 2 64 3 91 0 172 257 398 662 695 2
1 0 2 64 4 91 0 172 193 336 600 630 2
1 0 2 96 1 91 0 172 514 647 910 952 3
1 0 2 96 2 91 0 172 260 401 664 697 2
1 0 2 96 3 91 0 172 172 316 579 609 2
1 0 2 96 4 91 0 172 129 274 538 566 2
2-23 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-9: CTS/ SMM Continuum Mode (continued)
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 0 2 128 1 91 0 172 386 523 786 823 2
1 0 2 128 2 91 0 172 195 338 602 632 2
1 0 2 128 3 91 0 172 129 275 538 566 2
1 0 2 128 4 91 0 172 97 243 507 534 2
1 0 5 32 1 91 0 69 1538 1639 1800 1875 5
1 0 5 32 2 91 0 69 775 901 1061 1109 3
1 0 5 32 3 91 0 69 513 646 807 845 2
1 0 5 32 4 91 0 69 385 522 682 716 2
1 0 5 64 1 91 0 69 770 895 1055 1102 3
1 0 5 64 2 91 0 69 389 526 686 719 2
1 0 5 64 3 91 0 69 257 398 559 587 2
1 0 5 64 4 91 0 69 193 336 497 523 2
1 0 5 96 1 91 0 69 514 647 807 845 2
1 0 5 96 2 91 0 69 260 401 561 590 2
1 0 5 96 3 91 0 69 172 316 476 502 2
1 0 5 96 4 91 0 69 129 274 435 459 2
1 0 5 128 1 91 0 69 386 523 683 716 2
1 0 5 128 2 91 0 69 195 338 498 525 2
1 0 5 128 3 91 0 69 129 275 435 459 2
1 0 5 128 4 91 0 69 97 243 404 427 1
1 0 10 32 1 91 0 34 1538 1639 1765 1839 5
1 0 10 32 2 91 0 34 775 901 1027 1073 3
1 0 10 32 3 91 0 34 513 646 772 809 2
1 0 10 32 4 91 0 34 385 522 648 680 2
1 0 10 64 1 91 0 34 770 895 1021 1067 3
1 0 10 64 2 91 0 34 389 526 652 684 2
1 0 10 64 3 91 0 34 257 398 524 552 2
1 0 10 64 4 91 0 34 193 336 462 487 2
2-24 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-9: CTS/ SMM Continuum Mode (continued)
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS Integration Time CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 0 10 96 1 91 0 34 514 647 773 809 2
1 0 10 96 2 91 0 34 260 401 526 554 2
1 0 10 96 3 91 0 34 172 316 442 466 2
1 0 10 96 4 91 0 34 129 274 400 423 1
1 0 10 128 1 91 0 34 386 523 649 681 2
1 0 10 128 2 91 0 34 195 338 464 489 2
1 0 10 128 3 91 0 34 129 275 400 423 1
1 0 10 128 4 91 0 34 97 243 369 391 1
1 0 20 32 1 91 0 17 1538 1639 1748 1821 5
1 0 20 32 2 91 0 17 775 901 1009 1055 3
1 0 20 32 3 91 0 17 513 646 755 791 2
1 0 20 32 4 91 0 17 385 522 631 662 2
1 0 20 64 1 91 0 17 770 895 1004 1049 3
1 0 20 64 2 91 0 17 389 526 634 666 2
1 0 20 64 3 91 0 17 257 398 507 534 2
1 0 20 64 4 91 0 17 193 336 445 470 2
1 0 20 96 1 91 0 17 514 647 755 792 2
1 0 20 96 2 91 0 17 260 401 509 536 2
1 0 20 96 3 91 0 17 172 316 424 448 2
1 0 20 96 4 91 0 17 129 274 383 405 1
1 0 20 128 1 91 0 17 386 523 631 663 2
1 0 20 128 2 91 0 17 195 338 447 471 2
1 0 20 128 3 91 0 17 129 275 383 363405 1
1 0 20 128 4 91 0 17 97 243 352 373 1
2-25 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-10: CTS Dual Continuum Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 1 1 32 1 91 344 344 1538 1639 2419 2517 6
1 1 1 32 2 91 344 344 775 901 1680 1751 5
1 1 1 32 3 91 344 344 513 646 1426 1487 4
1 1 1 32 4 91 344 344 385 522 1301 1358 4
1 1 1 64 1 91 344 344 770 895 1674 1745 5
1 1 1 64 2 91 344 344 389 526 1305 1362 4
1 1 1 64 3 91 344 344 257 398 1178 1230 3
1 1 1 64 4 91 344 344 193 336 1116 1165 3
1 1 1 96 1 91 344 344 514 647 1426 1487 4
1 1 1 96 2 91 344 344 260 401 1180 1232 3
1 1 1 96 3 91 344 344 172 316 1095 1144 3
1 1 1 96 4 91 344 344 129 274 1054 1101 3
1 1 1 128 1 91 344 344 386 523 1302 1359 4
1 1 1 128 2 91 344 344 195 338 1118 1167 3
1 1 1 128 3 91 344 344 129 275 1054 1101 3
1 1 1 128 4 91 344 344 97 243 1023 1069 3
1 2 2 32 1 91 172 172 1538 1639 2075 2160 6
1 2 2 32 2 91 172 172 775 901 1336 1394 4
1 2 2 32 3 91 172 172 513 646 1082 1130 3
1 2 2 32 4 91 172 172 385 522 957 1001 3
1 2 2 64 1 91 172 172 770 895 1330 1388 4
1 2 2 64 2 91 172 172 389 526 961 1005 3
1 2 2 64 3 91 172 172 257 398 834 873 3
1 2 2 64 4 91 172 172 193 336 772 808 2
1 2 2 96 1 91 172 172 514 647 1082 1131 3
1 2 2 96 2 91 172 172 260 401 836 875 3
1 2 2 96 3 91 172 172 172 316 751 787 2
1 2 2 96 4 91 172 172 129 274 710 744 2
2-26 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-10: CTS Dual Continuum Mode (continued)
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 2 2 128 1 91 172 172 386 523 958 1002 3
1 2 2 128 2 91 172 172 195 338 774 810 2
1 2 2 128 3 91 172 172 129 275 710 744 2
1 2 2 128 4 91 172 172 97 243 679 712 2
1 5 5 32 1 91 69 69 1538 1639 1868 1946 5
1 5 5 32 2 91 69 69 775 901 1130 1180 3
1 5 5 32 3 91 69 69 513 646 875 916 3
1 5 5 32 4 91 69 69 385 522 751 787 2
1 5 5 64 1 91 69 69 770 895 1124 1174 3
1 5 5 64 2 91 69 69 389 526 755 791 2
1 5 5 64 3 91 69 69 257 398 627 659 2
1 5 5 64 4 91 69 69 193 336 565 594 2
1 5 5 96 1 91 69 69 514 647 876 916 3
1 5 5 96 2 91 69 69 260 401 630 661 2
1 5 5 96 3 91 69 69 172 316 545 573 2
1 5 5 96 4 91 69 69 129 274 503 530 2
1 5 5 128 1 91 69 69 386 523 752 788 2
1 5 5 128 2 91 69 69 195 338 567 596 2
1 5 5 128 3 91 69 69 129 275 504 530 2
1 5 5 128 4 91 69 69 97 243 472 498 2
1 10 10 32 1 91 34 34 1538 1639 1800 1875 5
1 10 10 32 2 91 34 34 775 901 1061 1109 3
1 10 10 32 3 91 34 34 513 646 807 845 2
1 10 10 32 4 91 34 34 385 522 682 716 2
1 10 10 64 1 91 34 34 770 895 1055 1102 3
1 10 10 64 2 91 34 34 389 526 686 719 2
1 10 10 64 3 91 34 34 257 398 559 587 2
1 10 10 64 4 91 34 34 193 336 497 523 2
2-27 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-10: CTS Dual Continuum Mode (continued)
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
1 10 10 96 1 91 34 34 514 647 807 845 2
1 10 10 96 2 91 34 34 260 401 561 590 2
1 10 10 96 3 91 34 34 172 316 476 502 2
1 10 10 96 4 91 34 34 129 274 435 459 2
1 10 10 128 1 91 34 34 386 523 683 716 2
1 10 10 128 2 91 34 34 195 338 498 525 2
1 10 10 128 3 91 34 34 129 275 435 459 2
1 10 10 128 4 91 34 34 97 243 404 427 1
1 20 20 32 1 91 17 17 1538 1639 1765 1839 5
1 20 20 32 2 91 17 17 775 901 1027 1073 3
1 20 20 32 3 91 17 17 513 646 772 809 2
1 20 20 32 4 91 17 17 385 522 648 680 2
1 20 20 64 1 91 17 17 770 895 1021 1067 3
1 20 20 64 2 91 17 17 389 526 652 684 2
1 20 20 64 3 91 17 17 257 398 524 552 2
1 20 20 64 4 91 17 17 193 336 462 487 2
1 20 20 96 1 91 17 17 514 647 773 809 2
1 20 20 96 2 91 17 17 260 401 526 554 2
1 20 20 96 3 91 17 17 172 316 442 466 2
1 20 20 96 4 91 17 17 129 274 400 423 1
1 20 20 128 1 91 17 17 386 523 649 681 2
1 20 20 128 2 91 17 17 195 338 464 489 2
1 20 20 128 3 91 17 17 129 275 400 423 1
1 20 20 128 4 91 17 17 97 243 369 391 1
2-28 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Table 2.5-11: Asteroid Mode
HousekeepingOn/Off # of Summed 50-msec Continuum-mm Integrations # of Summed 50-msec Continuum-smm Integrations CTS IntegrationTime CTS SmoothingShift HK Rate (bps) CON/mm Rate (bps) CON/smmRate (bps) CTS Rate (bps) CTS Rate IncludingCalibration (bps) Overall Rate (bps) Overall + ESA Packet Overhead (bps) Data Mode
Data rates do not exceed the rate of output as when the instrument is in CTS/Dual Continuum. See 6.1.2.2.4.3
2-29 EXPERIMENT CONFIGURATION
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
2.6 NON-OPERATING HEATERS
(None)
2.7 SPACECRAFT POWERED THERMISTORS
2 main and 1 redundant
2.8 PYRO LINES
The MIRO instrument uses no pyrotechnic devices.
2.9 OBDH CHANNEL
2.9.1 CHANNEL ALLOCATION
MIRO's channel allocations are listed in Table 2.9-1.
Table 2.9-1: Experiment OBDH Interface Channels/Functions
Interface Signal Type or Function Main Redundant
Telecommand Channels Memory Load Commands 1 1
High Power On/Off Commands 0 0
Telemetry Channels 16-bit Serial Digital Channel 1 1
Fast Serial Interface (typ. Mbps) N/A N/A
Monitor Channels Spacecraft Powered Thermistors 2 1
Bilevel Channels 0 0
Analogue Channels 0 0
Timing Channels High Frequency Clock 0 0
Broadcast Pulse (TSY) 1 1
Special Synchronization Channels Converter Synchronization Signal N/A N/A
Frequency reference N/A N/A
2.9.2 TELEMETRY
MIRO will send telemetry source packets which consist of both Science Packets and Science Housekeeping Packets. MIRO source packets will conform to the ESA Packet Telemetry Standard, ref. PSS-04-106, Iss. 1.
2.9.3 TELECOMMAND
MIRO telecommand packet will be consistent with the format as defined in the ESA Telecommand Standard, ref. PSS-04-107, Iss. 2. Telecommand will provide the following at a minimum: Instrument commands, memory loads and broadcast time.
MIRO has no requirement for discrete commands through the RTU.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
2.9.4 BIT RATE REQUIREMENTS
The engineering and scientific bit rates are given in Volume 6, Table 6.4.3-1 of the EID-B. The optimum bit rate is the highest bit rate and occurs for the full calibration mode. The minimum rate occurs for the millimeter continuum mode. There are no special requirements (high speed data transmissions for defined period).
There are no specific constraints or preferences for the implementation of the Packet Telemetry, i.e., whether variable or fixed packet length per mode or limitations on maximum packet size.
MIRO will provide a 16-bit word that indicates the length of the packets if a packet is available or zero if no packet is ready for pickup.
2.9.5 TIMING
S/C time updates will be sent to MIRO along with the TSY pulse for synchronizing. MIRO will use its internal clock and counters to add to the S/C time updates. No S/C High Speed Clock is required as long as the period between S/C updates is less than 1 hour.
2.9.6 MONITORING
The DMS is expected to monitor parameters from the housekeeping packets and compare values to a stored table to determine anomalies. Results are stored to be downloaded for further investigation.
2.9.6.1 Telecommands and Verification
MIRO telecommands and verification is discussed in EIDB-2.8.
2.9.6.2 Experiment Status and Event Reporting
MIRO experiment status and event reporting is discussed in EIDB-2.8.
2.9.7 ELECTRICAL INTERFACES CIRCUITS
2.9.7.1 General
MIRO's electrical interface will be compatible with the RTI interface specified in the Spacecraft Data Handling Interface Standard, ref. ES-PSS-47/TTC-B-01, Iss. 1.
A Standardized Balanced Digital Link (SDBL) will be used to perform the serial data transmission.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
2.9.7.2 Telemetry
Refer to Figure 2.9-1 the implementation of Telemetry interface circuits.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
2.9.7.3 Telecommand
Refer to Figure 2.9-2 for the implementation of the Telecommand interface circuits. MIRO does not require switch closure or high power on/off commanding.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
2.9.7.4 Broadcast Pulse (TSY)
Refer to Figure 2.9-3 for the implementation of the Broadcast Pulse (TSY) interface circuit.
Figure 2.9-3: Broadcast Pulse (TSY) Circuit Interface
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
2.9.7.5 Environmental and Status Monitoring
Two temperature sensors within MIRO will be monitored by the S/C. One located
near the sensor electronics and the other on the optical bench. Only the sensor on
the optical bench will have a redundant temperature sensor.
2.9.7.6 Redundancy
MIRO will provide for redundancy on all signal lines to/from the OBDH. MIRO
will design its interface circuits to prevent a single failure from propagating to its
redundant interface.
MIRO is configured as non-redundant and will OR the main and redundant signal
in such a way as to enable proper operation if either signal is stuck in its high or
low state.
MIRO will provide both a main and redundant signal to the OBDH.
2.9.8 ON-BOARD OPERATIONAL INTERFACE WITH DMS
The following sections describe in general terms the operational interface between payload units and the DMS.
2.9.8.1 Telecommand
MIRO will receive commands sent from the ground or generated within the DMS. MIRO will be capable of receiving the commands at 131K bits per second MIRO will support a maximum data volume of 1024 bytes within a 0.2-second period.
2.9.8.2 Telemetry
Data of different types will be collected and are as follows:
1. Housekeeping Data
MIRO science housekeeping packet will contain those channels that will indicate the instrument's health, provide data to determine instrument's operating temperatures and its operation modes. The MIRO science housekeeping packets will contain verification of commands received.
2. Science Data
MIRO will provide both the science and science housekeeping to the S/C over a
common interface. The MIRO analogue channels will be converted to
housekeeping channel.
3. Large Data File Transfer
The DMS shall provide storage for data file to be used for MIRO program
changes. Data rate and storage required are defined in EIDB Volume 6. This is
based on MIRO operating out of RAM where initially program would be moved
from EEPROM to RAM but if program is to be changed after launch, the new
program would be uploaded to the DMS and then from the DMS to MIRO.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
EXPERIMENT OPERATIONS
3.1 OPERATING PRINCIPLES
MIRO has four (4) major types of operations during the Rosetta Mission:
1.
Warmup of CTS and USO
2.
Functional Tests
3.
In-Flight Calibration Observations
4.
Primary Scientific Observations
3.1.1 INSTRUMENT POWER ON, WARMUP, AND STABILIZATION
Two parts of the MIRO instrument require a warmup period to stabilize their electronics for in spec performance. These are the Chirp Transform Spectrometer (CTS), an assembly of the Electronics Unit, and the Ultra-Stable Oscillator (USO) Unit. During this warmup period, these components require power above their nominal operating state. To minimize the impact of this additional power need, the instrument power switches are configured such that most other MIRO components are off. The warmup sequence is performed automatically at instrument turn on and requires about 30 minutes for the CTS and at least 4 hours for the USO. MIRO may begin operations (acquisition of data) after the CTS warmup with the realization that the USO may not be completely stable and analysis will have higher error bars. Note that spectroscopic data acquired before the CTS is fully warmed up have a high risk of being completely meaningless.
3.1.2 FUNCTIONAL TESTS
The functional tests will turn on and functionally check out the instrument after any prolonged period during the mission in which the instrument has been turned off. Such periods include the launch and cruise phases of the mission. These tests consist of turning on the instrument such that all types of data are collected (engineering, continuum and spectroscopic) and commanding several parameter changes in order to ascertain the health and status of the instrument.
3.1.3 IN-FLIGHT CALIBRATION OBSERVATIONS
MIRO will need to perform in-flight calibrations periodically during the mission to check the absolute frequency response. During these observations, MIRO will point at various celestial sources, including Venus, Jupiter, Mars (at a distance) and (Galactic) instellar molecular clouds as well as MIRO's internal "hot" and "cold" targets. Table 3.1-1 contains a summary of the calibration goals during the mission and Table 3.1-2 prioritizes them. Details of the calibrations are described in Section 3.2 of this document.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Table 3.1-1: MIRO Calibration/Observing Needs
Operation Phase Modes Used (Ref: EID-B Table 6.3.1-1) Targets Calibration Attributes
Internal Loads Earth Moon Mars Celestial Asteroid Comet Beam Radiometer Frequency Spectrometer Limb Mapping Boresighting
Launch phase H - - - - - - - - - - - - - -
Commissioning-1 [1-17] C C C - C - - C C C C C C C
Cruise phase 1 [1-6], H - - - - C - - C C - - - - C
Commissioning-2 [1-17] C C C - C - - C C C C C C C
Earth flyby 1 [1-6], [13-4] C C C - - - - C C C C C - C
Cruise phase 2 H - - - - - - - - - - - - - -
Mars flyby [1-6], [13-4] - - - C - - - C C C C - - C
Cruise phase 3 H - - - - - - - - - - - - - -
Earth flyby 2 [1-6], [13-4] C C C - - - - C C C C C - C
Cruise phase 4-1 H - - - - - - - - - - - - - -
Steins flyby [1-6], [13-4] C - - - - S - C C - - - C C
Cruise phase 4-2 H - - - - - - - - - - - - - -
Earth flyby 3 [1-6], [13-4] C C C - - - - C C C C C - C
Cruise phase 5 H - - - - - - - - - - - - - -
DSHM Commissioning H - - - - - - - - - - - - - -
Lutetia flyby [1-6], [13-4] C - - - - S - C C - - - C C
Cruise phase 6 (DSHM) H - - - - - - - - - - - - - -
Comet drift phase [1-6], [13-14], [15], [16] C - - - - - S - C - - - - C
Far approach [1-6], [7-12], [13,14], [15], [16] C - - - - - S - C - - - - C
Close approach [1-6], [7-12], [13,14], [15], [16] C - - - - - S - C - - - - -
Transition to global mapping [1-6], [7-12], [13,14], [15], [16] C - - - - - S - C - - - - -
Nucleus map./close enc. [1-6], [7-12], [13,14], [15], [16] C - - - - - S - C - - - - -
Comet low activity phase [1-6], [7-12], [13,14] C - - - - - S - C - - - - -
Comet activity: moderate increase [1-6], [7-12] C - - - - - S - C - - - - -
Comet activity: sharp increase [1-6], [7-12] C - - - - - S - C - - - - -
Comet activity: high activity [1-6], [7-12] C - - - - - S - C - - - - -
Near perihel phase [1-6] C - - - - - S - C - - - - -
Extended mission TBD - - - - - - - - - - - - - -
Notes:
1.
C (calibration) and S (science) refer to primary purpose of the observations;
2.
Target sources may either be used for calibration or science; celestial sources include Venus, Jupiter, Mars (at a distance) and (Galactic) interstellar molecular clouds
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Table 3.1-2: Calibration Priorities (1 = highest)
Calibration Elements Moon Earth Mars Celestial
Field of View (beam) 1 2 3 4
Radiometric (power) 1 2 3 4
Frequency (knowledge) x 2 1 3
Spectrometer (function) x 2 1 3
3.1.3.1 Radiometric
The principal radiometric calibration opportunity is the close observation of the Moon during the Earth swing-bys. MIRO continuum maps will be compared to detailed Moon models in order to perform the calibration.
3.1.3.2 Frequency
Opportunities for frequency calibration of the CTS will occur with nearby observations of Mars and Earth, in which several known spectral lines will be observed with high accuracy.
3.1.3.3 Field of View
Calibration of the FOV and offset of the MIRO beams requires a target that is bright enough to give a strong signal in the continuum detectors and distant enough to be of an angular size much less than the beamwidths. The best candidate for this is the Earth, well away from the swing-bys.
3.1.4 PRIMARY SCIENTIFIC OBSERVATIONS
MIRO will acquire science data during the Asteroid Flybys and during Comet Approach, Mapping and Close Encounter, and Escort to Perihelion phases, as well as for targets (typically comets) of opportunity. Continuum, spectroscopic and calibration data will be taken during these times. These primary operating modes of MIRO are described in Section 6.1.2.1.1 of this User Manual.
Table 3.1-1 summarizes when science observations with MIRO will occur. Section 3.2 of this document describes in more detail, the types of data acquired during these phases.
Some special modes are described in the next section.
3.1.4.1 Asteroid Mode
A special mode was designed for the asteroid encounters, in which a large amount of spectroscopic data are acquired in a short period of time (maximum 18 minutes) and then played back during several hours after that. When using this mode, care must be taken in the observation design to allow sufficient time after the primary observations to play back all the data, including as much of the post-asteroid mode data as are desired.
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Note that this mode is not necessarily limited to use in asteroid encounters. It can also be of use in any close encounter with a target.
The Asteroid Mode telecommand is described in Section 6.1.2.2 of this User Manual.
3.1.5 MIRO FLIGHT COMPUTER MEMORY OPERATIONS
The MIRO flight software is capable of being patched with updates from the ground. This capability has been tested before launch; however, the procedure for doing this in flight has yet to be worked out.
It should be noted that due to a bug, the Memory Checksum command in the MIRO flight software only includes every other memory location in the checksum, i.e., half the total memory requested. Therefore, in order to ensure that the EEPROM has not suffered any radiation damage, it is necessary to dump the entire area and perform the check on the ground.
3.1.6 THERMAL OPERATING LIMITS
The principal thermal concern is overheating of the Gunn oscillators in the mm-wave and submm-wave heterodyne receivers mounted on the optical bench in the Sensor Unit, which may cause degradation of the longevity of some components. Therefore, we require that the instrument be switched off if the Optical Bench temperature exceeds 45 degrees C.
3.1.7 OPTIMIZING DATA TAKING
Certain commands are designed to optimize the efficiency and stability of data acquisition. These include the Calibration Heater command, the CTS Runtime command, which controls the "CTS gap" and the Housekeeping Cycle Skip command.
3.1.7.1 Calibration Heater
There are two calibration loads in the MIRO instrument, one internal to the Sensor Unit and one mounted externally under the primary mirror of the telescope. The MIRO instrument is radiometrically calibrated by correlating its measured response when looking at each of the calibration loads with their physical temperature. For this calibration to be accurate, the difference in the two loads' temperature should be greater than 30 C. The cold load will be at the temperature of the external environment. This is expected to become quite cold when the Rosetta spacecraft is far from the sun. The warm load is at the ambient temperature inside the spacecraft maintained between -20 C and +50 C. The purpose of the calibration heater is increase the temperature of the warm load should the two loads be within 30 C of each other. The calibration heater command, when turned on supplies current to a heater on the warm calibration load. With this current applied the warm load heats up about 30 C above its ambient temperature. When the calibration heater is turned off, the warm load temperature returns to ambient.
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The Calibration Heater telecommand is described in Section 6.1.1.1 of this User Manual.
3.1.7.2 CTS Gap
In modes where both CTS and continuum data are being acquired, the CTS gap is the time between the end of the readout of a given continuum packet and the start of the next CTS scan. Reducing this gap increases the speed of data generation; however, it must not be so small that the CTS scan and the continuum readout overlap, as this will cause an instrument failure (power-off). The value of the gap is reported in the Miscellaneous Science packets, and it can be changed by varying the parameters of the CTS Runtime command, which sets the duration of a CTS scan.
The CTS Runtime telecommand is described in Section 6.1.5.8 of this User Manual.
3.1.7.3 Housekeeping Cycle Skip
The digital noise generated when reading the engineering housekeeping data every 11 seconds can cause excess noise in the continuum data. The engineering housekeeping cycle skip command can be used to skip this readout for a certain period of time in order to eliminate this noise source.
The Housekeeping Cycle Skip telecommand is described in Section 6.1.3.1 of this User Manual.
3.2 OPERATING MODES
3.2.1 GROUND TEST PLAN
The ground test plan for MIRO, both EQM and FM includes tests for electrical and functional verification including the spacecraft interfaces and a full set of environmental tests (vibration, shock, thermal/vacuum and EMC). Tests that will be performed on the flight model which are not performed on the EQM are optical alignment tests and detailed calibration tests. In addition, the MIRO STM performed qualification level vibration testing of each unit.
For functional and interface verifications (not including the detailed electrical verification and EMC test), a set of test sequences are defined (see Attachment 4 of this document). The following tests are defined:
*
Full Functional Test (FFT)
*
Bench Test (BT)
*
Unit Functional Test (UFT)
*
Integrated System Test (IST)
*
Special Performance Test (SPT)
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3.2.2 IN-ORBIT COMMISSIONING PLAN (MIRO EID-B, 6.3.2.2)
MIRO will initially undergo a checkout procedure during the commissioning phase, followed by tests to establish baseline performance of the instrument. MIRO will run through its operational modes, and will provide calibration and housekeeping data. As an essential part of 1) the instrument pointing and alignment, and 2) the radiometric calibration of both the millimeter and submillimeter-wave receivers, the MIRO instrument will observe the Moon, the Earth and Celestial sources (Venus, Jupiter, Mars or Galactic) as available. Observations will be required at times which are not tightly constrained (within a 10-day period TBC). Two sets of observations are desired; one set preferably timed to be late in the commissioning period when the Earth or Moon are smaller than the smallest MIRO beamwidth (7 arc min), and a second set when either source is large relative to the MIRO beamwidths so that its limb may be scanned. The Moon is a valuable source for gain calibration because it was extensively observed by the Cosmic Microwave Background Explorer and its microwave brightness temperature distribution is well understood. Observations of the Moon when it is smaller than the MIRO beamwidth will enable the verification of the antenna on-axis gain to within approximately 2%. Observations when the Moon is larger than the beamwidth will enable the verification of the main beam efficiency and will enhance confidence in our ability to determine absolute brightness temperatures of the comet nucleus. These observations will require up to four hours each, (more time than when the Moon is smaller than a beamwidth) since mapping is required.
3.2.3 INSTRUMENT CHECKOUT
During the regular payload checkout activities, MIRO will run a standard sequence (AMRF100A, see FOP) in which as many modes and commands are exercized as possible. In addition, a dump of EEPROM memory (AMRF101A, see FOP) will be performed in order to check for radiation damage (see 3.1.5).
3.2.4 FLIGHT OPERATIONS PLANS (MIRO EID-B, 6.3.2.3)
This section covers the post-launch operation of MIRO in conjunction with the overall operations of the Rosetta spacecraft. The MIRO science team will conduct its mission operations through the Rosetta Science Operations Centre (RSOC) as described below. The operations requirements for MIRO are given for all phases of the mission, from launch until the end of the mission, making use of the facilities provided to the MIRO team by ESOC. This portion of Volume VI is a response to Volume VI of the Rosetta EID-A and is to be read in that context. Specifically, the Mission Operations description and definitions of terms appearing in that document are not repeated here.
The following sections describe the requirements of the MIRO instrument during the mission phases described in Section 6.2 of the EID-A.
3.2.4.1 Launch Phase
MIRO was off during launch phase.
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3.2.4.2 Cruise Phases
MIRO was generally be switched off during the cruise phases with the exception of the calibration periods, periodic instrument checkouts, and observations associated with the Deep Impact mission and Comet C/2002 T7 (LINEAR).
3.2.4.3 Mars Gravity Assist
Mars observations in both the continuum and spectral modes are desired to obtain spectral calibration and confirmation of pointing parameters, to be obtained toward the end of the Mars Gravity Assist period after close encounter and before the apparent disk of Mars decreases below the MIRO beamwidths. Both centered (boresighted) and limb sounding observations are desired. The asteroid mode may be used for these observations. [Update for Version 6.0: MIRO was not turned on during the Mars flyby because power constraints would not have allowed it to be turned on long-enough to warm-up and stabilize.]
3.2.4.4 Earth Gravity Assists
A minimal instrument turn-on and checkout procedure was performed during the three Earth flybys. Earth observations in spectral modes were made to confirm spectral calibration. Observations of the Moon in continuum mode were made to determine pointing parameters and establish gain calibrations.
3.2.4.5 Steins Fly-by
The flyby of Steins was the first opportunity for science observations by MIRO, which was turned on and fully operational during this phase. Continuum radiometry and submillimeter spectroscopy was performed, via the asteroid mode, to search for low levels of gas (water) and evaluate the thermal and electrical properties of the asteroid.
3.2.4.6 Lutetia Fly-by
MIRO operations at Lutetia were the same as those for Steins.
3.2.4.7 Deep Space Hibernation Mode (DSHM)
MIRO remained switched off during this phase.
3.2.4.8 Rendezvous Manoeuvre
MIRO was switched off during this phase.
3.2.4.9 Comet Drift Phase
Instrument turn-on and checkout procedure were performed during this phase and brief periods of comet observations.
3.2.4.10 Comet Approach Navigation and Maneuvering
MIRO was typically turned on and fully operational during this and all subsequent phases.
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3.2.4.11 Nucleus Mapping and Close Observation
MIRO will operate primarily in continuum mode during this phase and will support the mission's nucleus characterization effort. By mapping the area near the lander the surface emissivity can be characterized using in situ temperature measurements from the lander. If power is available, spectroscopic mode will be used as well. [Update for Version 6.0: MIRO was typically turned on and fully operational during this and all subsequent phases.]
3.2.4.12 SSP Delivery and Comet Escort to Perihelion
Observations during this phase are MIRO's prime mission objective. MIRO will operate in all modes, and will observe the nucleus in both continuum and spectroscopic modes with as large a range of solar phase angles as possible, and will observe the coma in all possible directions from the spacecraft relative to the nucleus. [Update for Version 6.0: MIRO was typically turned on and fully operational during this and all subsequent phases.]
3.2.5 INTERFERENCES
At the present time, no interferences between MIRO and other instruments or subsystems have been definitely established, although disturbances are occasionally seen in the data that could be due to interference. It is intended to continue to monitor the MIRO data during periods of operation for signs of interference from other instruments or from the spacecraft. No restrictions need to be placed on the MIRO instrument because of interference from other instruments or the spacecraft.
3.2.6 OPERATIONAL CONSTRAINTS
The following operational constraints exist for MIRO:
1. Instrument constraints related to warming up (see 3.1.10): It is imperative that CTS warmup be started at least 30 minutes before the
CTS is turned on; if this is not done, there is a high probability that the CTS data will be invalid.
It is desirable that the USO be stable during CTS operations, but since full stabilization can take 8 hours (or more), it is permissible to start the CTS soon after CTS warmup has been performed (above), with the realization that the data will have higher noise than after stabilization has been achieved. Normally, the USO should be turned on at least 2 hours before the CTS is started up.
2. Commanding constraints. The following constraints exist on the instrument
commands that switch various modules on and off: USO: cannot be powered off from any CTS mode; otherwise, it can be powered on or off from any mode.
MM LNA: this is powered on automatically when MIRO goes into MM
Continuum, Dual Continuum and CTS/Dual Continuum modes. It can be
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powered on or off in these modes only, not in any other mode. It can only be
powered on after it has been powered off without a mode change.
SMM LNA: same as MM LNA, with the substitution of SMM for MM.
CTS Warmup: this command can only be issued from a non-CTS mode; the CTS warmup is automatically switched off by any mode change to a non-CTS mode, and this is the only way in which it can be turned off.
CTS Heater: this command can only be issued from a CTS mode. Note that the CTS heater is turned on automatically when any CTS mode is entered, but the temperature and heating rate are then set to default values.
3.
Pointing constraint: the MIRO boresight shall not be closer than 5 degrees from the Sun.
4.
Power constraint: there is a latching current limit (LCL) of 109W / 4A (Ref. EID-B Section 2.4.1, Table 2.4-1).
5.
Thermal constraint: the Optical Bench temperature should not exceed 45 degrees C; if this is exceeded, MIRO should be turned off (see 3.1.6).
6.
Interferences (see 3.2.5): No restrictions need to be placed on the MIRO instrument because of interference from other instruments or the spacecraft.
3.3 FAILURE DETECTION AND RECOVERY STRATEGY
The MIRO instrument is a single string instrument. Accordingly, there is little that can be done in the event of a major instrument failure. Table 3.3-1 summarizes the possible failure modes and describes the consequences of each. Also refer to EID-B 6.5.4 for recovery procedures.
In order to prevent the instrument temperatures from rising to excessively high values during observations in which there is no ground contact with the spacecraft for extensive periods, there is an on-board monitoring procedure on the Optical Bench temperature (NTSA0194), which will turn off MIRO by OBCP if this item exceeds 45 degrees C for more than 30 consecutive seconds.
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Table 3.3-1: MIRO Failure Modes and Possible Recovery Operations
Assembly/Subassembly Failure Response
Mirror Motor Complete failure to operate Activate the pin puller mechanism that will disengage the mirror from the motor. Once disengaged, the spring-loaded mirror will move to the "Space" position. Calibration target data will be lost
Mirror LEDs for Failure to indicate Error codes returned in anomaly packets need to be
positioning position analyzed to determine if this failure is permanent. If permanent failure, only recovery is to re-write flight software to count steps to each calibration target position.
mm-receiver Failure of component May be able to bring component back into operation by changing operating parameter. Worse case is complete loss of mm continuum data.
Submm-receiver Failure of component May be able to bring component back into operation by changing various operating parameters. Worse case is complete loss of submm continuum data and all spectroscopic data.
Signal processing electronics Failure of key component Depending on component that fails, may be recoverable via operating parameters. Some data loss will happen.
Main electronics Failure of key component Depending on component that fails, may be recoverable via operating parameters. Some data loss will happen.
Power Controller Electronics Failure of DC/DC Converter Depending on which power converter fails, some recovery is possible
Failure of CPU Failure of electronics Not recoverable
Failure of CTS Failure of electronics Loss of spectroscopic data
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MODE DESCRIPTIONS
The MIRO instrument has 7 major modes based on power: 1) Engineering;
2) millimeter continuum; 3) submillimeter continuum; 4) dual continuum;
5) CTS/submillimeter-wave continuum; 6) CTS/dual continuum; and 7) Asteroid.
The power levels for each mode are given in Table 2.5-2. The data rates for a given mode are dependent on the parameters selected. Typical data rates for modes 1 thru 6 are given in Tables 2.5-5 thru 2.5-10. The data rate for asteroid mode is approximately 27 kbits/s. The parameters for each mode are described in more detail in Flight Software Requirements Document, RO-MIR-RS-0005.
When the MIRO instrument is initially powered on it will enter engineering mode upon receipt of a time update telecommand from the spacecraft. Engineering mode telemetry will be sent to the spacecraft within 1 minute following the time synchronization telecommand.
4.1 MODE TRANSITION TABLE
Table 4.1-1 shows the mode transitions possible with the MIRO instrument. With the exception of the asteroid mode, it is possible to change from any operational mode to any other operational mode. The asteroid mode can only be entered from the dual continuum and exited to dual continuum. The exit to dual continuum is automatic and does not require a separate mode change command. The instrument can be powered off from any mode without harm to the instrument, however in normal operation it is best to reenter the engineering mode before powering off.
A mode change command is issued to the MIRO software to switch between modes. The mode change command contains 4 controlling parameters:
1.
Power mode (the 6 defined above)
2.
CTS integration period (30, 60, 90, or 120 seconds)
3.
CTS smoothing value
4.
Continuum summing value (1, 2, 5, 10, or 20)
The process of changing from one operational mode to another is begun via a graceful shutdown of the current mode. If the CTS is running as part of the current mode, then the current CTS integration period is allowed to complete. The telemetry data associated with the current scan, as well as the accumulating continuum data, are then flushed out. The software is then shut down.
If the CTS is not operating then the graceful shutdown is much simpler. If continuum data is being collected then the current 5-second (=100 samples, dependent on summing value) collection cycle is allowed to complete prior to shutting down the software. If engineering mode is the current mode then no graceful shutdown is required as engineering collection continues through all mode transitions.
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After the graceful software shutdown is complete, any required power state changes are made. This could result in numerous components either being powered on or off depending on the current mode and the commanded mode.
The start of each mode, except for engineering only mode, begins with an instrument calibration. The instrument calibration views the hot target for 30 seconds, the cold target for 30 seconds, and finally the space target for 30 seconds. CTS data collected during calibration is not subtracted based on LO frequency. Both LO data sets are returned. The continuum summing value in place when the mode is changed is controls the rate of continuum collection during the instrument calibration.
When the instrument calibration is complete the nominal processing mode is begun. The MIRO instrument will remain in nominal processing until it receives a mode change command or approximately 30 minutes have elapsed. After 30 minutes another instrument calibration is performed. Instrument calibration is performed with every mode change and every 30 minutes except when running in engineering only mode.
Engineering TM is generated during all of the MIRO operational modes.
Table 4.1-1: Mode Transition Table
TO MODE #
MODE NAME
#/# 1 2 3 4 5 6 7
Engineering FROM MODE # 1 0 Y Y Y Y Y N
mm continuum 2 Y 0 Y Y Y Y N
smm continuum 3 Y Y 0 Y Y Y N
Dual Continuum 4 Y Y Y 0 Y Y Y
smm spectroscopic (CTS) 5 Y Y Y Y 0 Y N
CTS/ Dual continuum 6 Y Y Y Y Y 0 N
Asteroid 7 N N N Y (A) N N 0
Note: The transition from Mode 7 (Asteroid) to Mode 4 (Dual Continuum) is automatic. This is indicated by Y(A) in the Table above.
4.2 DETAIL MODE DESCRIPTION
4.2.1 ENGINEERING MODE
While running in engineering mode the MIRO software is collecting engineering data from 56 internal sensors. The sampling of these sensors is at a 5 Hz rate. All engineering measurements are 12-bit A/D converted values. The engineering mode telemetry is sent to the spacecraft in the form of a housekeeping telemetry packet. One engineering telemetry packet is generated every 11 seconds, unless the Engineering Housekeeping Cycle Skip Telecommand has been executed with its parameter set to n not equal to zero. Then the telemetry packet is returned every (n+1)*11 seconds.
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The engineering TM is also generated during all the other MIRO operational modes.
4.2.2 MILLIMETER CONTINUUM MODE
While running in millimeter continuum mode the MIRO software has powered up the millimeter continuum portion of the electronics. Millimeter continuum data is collected at a 20 Hz. rate. All continuum data consist of 16-bit values. The millimeter continuum data is nominally packet into science telemetry packets every 10 seconds. A "summing value" parameter can cause the MIRO software to sum either 1, 2, 5, 10, or 20 separate continuum values prior to putting them into the telemetry packet. This feature can reduce the data rate to as little as one millimeter continuum packet every 200 seconds.
4.2.3 SUBMILLIMETER CONTINUUM MODE
Submillimeter continuum mode is very similar to millimeter continuum mode except a different set of electronics is powered on. The data collection and packing is identical to millimeter continuum mode. Millimeter and submillimeter continuum data are contained in separate science telemetry packets. A field in the source data header identifies which type of science data is contained in the telemetry packet.
4.2.4 DUAL CONTINUUM MODE
In dual continuum mode the millimeter and submillimeter continuum are being collected simultaneously. When running in dual continuum mode, the summing value parameter mentioned earlier is applied to both sets of data. This causes the same amount of millimeter and submillimeter data to be generated.
4.2.5 CTS / SUBMILLIMETER CONTINUUM MODE
This mode adds the collection of chirp transform spectrometer (CTS) data. The CTS is programmed by the MIRO software to run for an initial sub-integration period of approximately 5 seconds. An internal LO frequency generator is then switched and another 5-second period is observed. These pairs of observations are repeated with the respective results being summed over time. Selectable integration periods are 30, 60, 90, and 120 seconds. The data from the 2 LO frequencies are then subtracted from each other.
The CTS returns a total of 4096 channels of data. In normal processing each of the 4096 raw data measurements acquired during each capture period shall be right shifted 5 bits prior to further processing, except when MIRO is operating in Asteroid mode, where 5-bit shifting is skipped and the data set consists of the entire 32-bit CTS word being returned for each of the 4096 channels. The 4096 data values can be further reduced by application of a smoothing function whereby data from several channels are combined and weighted to produce fewer final channels. Smoothing window sizes are 1, 5, 7, and 9 channels. A mask is applied to the CTS data and only 12 bits of each resulting measurement is returned (see Section 6.1.5.7).
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CTS data collection and the LO frequency switching is coordinated with the collection of continuum data. When there is no continuum summing applied, exactly 100 continuum samples are taken during each LO frequency-switch setting. Upon receipt of the data on the ground it is known at which LO frequency all of the continuum measurements were made at.
If the CTS has just been powered on, an internal calibration of the CTS is performed. This consists of loading the 4 CTS sum of square tables with a linear ramping pattern. A 10,000-cycle integration is then performed and the resulting data read out. The data is then averaged to yield the mid-point of the table. The resulting mid-point values for each table are downlinked in telemetry packets for monitoring over time.
Note: Four CTS bands suffer from instablility due likely to an unstable amplifier; see CTS anomaly report RO-MIR-TN-2012-001-LWK.
4.2.6 CTS / DUAL CONTINUUM MODE
This is similar to CTS / SMM continuum mode except that the millimeter continuum data is also collected. As the CTS spectrometer and two continuum channels are operating simultaneously, the model is called CTS/Dual Continuum.
4.2.7 ASTEROID MODE
The Asteroid Mode is a special mode, intended to be used during the encounters with the two asteroids (but may be used elsewhere). In this mode, spectroscopic and continuum data are acquired in a short period of time (maximum 18 minutes) at a high data collection rate and then played back during several hours following the data collection. The mode is designed to improve sensitivity for detection of water (or other molecules) that might exist in a cloud around the asteroid. As seen from the spacecraft, any spectral lines of water will be blue shifted as the S/C approaches the asteroid, and red shifted as the S/C departs. These Doppler shifts due to the relative motion between the S/C and the asteroid cause the spectral line to rapidly move through the available passband. The purpose of the mode is to effectively widen the passband of the individual IFP bands by offsetting the LO by +/-5 MHz at specified times during the encounter. This process keeps the spectral line within the passband for approximately an extra minute or two depending on the flyby velocity and encounter distance.
The mode works as follows. On approach to the asteroid, the MIRO instrument will be commanded to be in Dual Continuum. At a specific spacecraft time specified by ground command, the instrument will be commanded into Asteroid mode and the local oscillator will be commanded to a specific setting (+/-5 MHz) where it will remain until closest approach at which time the local oscillator will shift in the opposite direction. While in Asteroid mode, the spectrometer and both continuum channels will be operating. The spectrometer will output data every 5 seconds with all 32 bits of 4096 channels-5-bit shifting does NOT occur as it does during normal data processing. This process extends the passband by 10
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MHz. At the end a specified time, the MIRO instrument will return to Dual Continuum mode.
The data rate associated with the asteroid mode requires a special discussion. While in asteroid mode, data is collected at one rate, buffered and then output at a different rate depending on the mode the instrument is in. While in asteroid mode, around 16 minutes or less, the output data rate is exactly the same as CTS/Dual Continuum data rate, which is 6 packets every collection cycle, which is nominally every 8 seconds.
Since the data collection rate while in asteroid mode is approximately 6 times faster than the output data rate, the buffered data have not been transferred to the S/C at the end of asteroid mode. When asteroid mode is finished it automatically switches to Dual Continuum mode, and the packet output rate then changes to the rate for Dual Continuum. This is 2 packets at most per collection cycle. This rate will continue until a mode change to any other mode, at which point the output rate will change to whatever rate that mode dictates. Thus the asteroid mode is unique in that its data rate is variable.
4.2.7.1 LO Settings in Asteroid Mode
The initial LO setting needs to be specified in asteroid mode. The initial LO setting is either LO 1 or LO 0; at closest approach to the asteroid, the LO is automatically switched to the opposite position. A setting of LO 1 shifts the LO + 5 MHz. A setting of LO 0 shifts the LO - 5 MHz. The particular setting needed depends on the molecule under consideration and on which sideband the line is in for each of its down-conversions. Table 4.2-1 gives the Initial LO settings for the principal molecules of interest for MIRO. The principal molecule of interest for the asteroid encounters is water. For water, the initial LO setting is LO 1.
Table 4.2-1: Initial LO Setting for Specific Molecules
Line Initial LO setting Frequency Shift in Spectrometer on Approach Frequency Shift in Spectrometer on Departure Spectrometer Frequencywith no shift (MHz)
H216O 1 - + 1270
H217O 1 - + 1300
CH3OH 0 + - 1320
H218O 1 - + 1340
CO 1 - + 1363
CH3OH 1 - + 1389
NH3 0 + - 1407
CH3OH 1 - + 1425
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CONTINGENCY RECOVERY AND FLIGHT CONTROL PROCEDURES/SEQUENCES
The following is a list of Contingency Recovery Procedures (CRP) and sequences, and Flight Control Procedures (FCP) and sequences for MIRO. This list is based on Issue 5.1 dated 26/07/2005. Details of procedures are contained in RO-ESC-PL-5000.
CRP-001 Emergency Switch-Off MR-FCP-001 MIRO Power On Engineering using OBCP MR-FCP-003 MIRO Power Off using OBCP MR-FCP-004 MIRO Power Off/Asteroid MR-FCP-007 MIRO Calibration Heater Power On MR-FCP-008 MIRO USO ON MR-FCP-009 MIRO CTS Warm-up MR-FCP-011 MIRO Mode Change to CTS/Dual Continuum MR-FCP-012 MIRO Mode Change to CTS/SMM MR-FCP-013 MIRO Mode Change to Dual Continuum MR-FCP-014 MIRO Mode Change to SMM Continuum MR-FCP-015 MIRO Mode Change to MM Continuum MR-FCP-016 MIRO Mode Change to Engineering MR-FCP-030 MIRO CTS Internal Calibration MR-FCP-031 MIRO MM LNA Power Off MR-FCP-032 MIRO SMM LNA Power Off MR-FCP-100 MIRO Instrument Checkout MR-FCP-101 MIRO EEPROM Memory Dump MR-FCP-200 MIRO Radio Source Boresight MR-FCP-210 MIRO Radiometric Calibration of the Moon MR-FCP-300 MIRO Point at Fixed Celestial Position MR-FCP-320 MIRO MAP/SCAN Object MR-FCP-500 MIRO Asteroid Observation MR-SEQ-301 Enable HK MR-SEQ-302 Disable HK MR-SEQ-402 Dump MIRO Memory MR-SEQ-403 Check MIRO Memory
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MR-SEQ-601 Set Submm Gunn Voltage
MR-SEQ-603 MM LNA Power
MR-SEQ-604 Submm LNA Power
MR-SEQ-605 MR IFP Power Control
MR-SEQ-607 Reset PLL
MR-SEQ-610 CTS Run Time
MR-SEQ-611 CTS Pulse Position
MR-SEQ-612 Move Mirror
MR-SEQ-613 MIRO SW Restart
MR-SEQ-614 MIRO Mode Change
MR-SEQ-615 CTS Thermal Control Command
MR-SEQ-617 MIRO CTS Data Masks
MR-SEQ-618 Continuum Subtraction Value
MR-SEQ-621 CTS Warmup
MR-SEQ-622 USO Off
MR-SEQ-623 SMM Gunn Voltage AutoCtrl Enable/Disable
MR-SEQ-624 MIRO Engineering Data Slow Down
MR-SEQ-631 Enable Science
MR-SEQ-632 Disable Science
MR-SEQ-722 Step Mirror
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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DATA OPERATIONS HANDBOOK (TELECOMMANDS)
6.1 TELECOMMANDS
MIRO is operated through telecommands. The telecommands are divided into six functional groups.
1.
Warm Up Telecommands
2.
Mode Change Telecommands
3.
Additional Engineering Mode Telecommands
4.
Additional Continuum Mode Telecommands
5.
Additional Spectroscopic Mode Telecommands
6.
Calibration Mirror Control Telecommands
7.
Software Telecommands
8.
Spacecraft Interface Telecommands
Each telecommand has parameters with a set of fixed values that can be assigned to them.
6.1.1 WARM UP TELECOMMANDS
The warm up telecommands are used when MIRO is first powered up.
6.1.1.1 Calibration Heater Telecommand
6.1.1.1.1 Description
There are two calibration loads in the MIRO instrument, one internal to the Sensor Unit and one mounted externally under the primary mirror of the telescope. The MIRO instrument is radiometrically calibrated by correlating its measured response when looking at each of the calibration loads with their physical temperature. For this calibration to be accurate, the difference in the two loads' temperature should be greater than 30 C. The cold load will be at the temperature of the external environment. This is expected to become quite cold when the Rosetta spacecraft is far from the sun. The warm load is at the ambient temperature inside the spacecraft maintained between -20 C and +50 C. The purpose of the calibration heater is increase the temperature of the warm (load should the two loads be within 30 C of each other.
The calibration heater command, when turned on supplies current to a heater on the warm calibration load. With this current applied the warm load heats up about 30 C above its ambient temperature. When the calibration heater is turned off, the warm load temperature returns to ambient.
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6.1.1.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 01100101 EID-A Optional, 101 = Calibration Heater Power
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-1 decimal: 0=Heater Off, 1=Heater On
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.1.1.3 Parameters The parameters are contained in the application data of the packet. Calibration heater state: On (1), Off (0)
6.1.1.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware.
6.1.1.1.4.1 Action Taken
Bit 14 of address 100 of the control register is set to the value specified.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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6.1.1.1.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. The direct effect of this command is that the temperature of the warm load should increase. The two temperatures, measured by two sensors on the Warm load should increase. In addition the current and voltage change on the supply lines. Also as mentioned above Bit 14 of address register 100 is set to 1.The typical effect on telemetry is summarized below. (Note that the actual voltages vary depending on the instrument state and may even go in the opposite direction. See expected values for telemetry in 7.1. However it should change.)
Calibration Heater Telecommand Off On
Control Bits
AddReg 100, Bit 14 (NMRA0005, bit 9) 0 1
Sensor Results
Warm Load 1 (NMRA0033) ambient ambient +30 C
Warm Load 2 (NMRA0044) ambient ambient +30 C
+24 V EU (NMRA0020) 23.1V 24.87
+24 V Current (NMRA0026) 0.02A 0.05A
The impact on the science data:
The measured continuum channels should increase. The measured spectroscopic calibration data should increase.
6.1.1.1.4.3 Additional Information
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to 0 (off).
6.1.1.1.5 RSDB Inputs
Telecommand: ZMR19208 -Calibration Heater Power
Parameters: PMRG0014 -PLL Reset, default 0, Off
CMRV0005 0, off 1, on
6.1.1.2 USO Power Telecommand
6.1.1.2.1 Description
The USO provides the frequency reference for spectroscopic measurements. It takes about 8 hours to stabilize. It is automatically turned on in the two
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spectroscopic modes. This commands allows it to be turned on in any mode so that it can warm up prior to initiating a spectroscopic mode.
6.1.1.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001011 EID-A Optional, 11 = USO Power
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-1 decimal: 0=USO Off, 1=USO On
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.1.2.3 Parameters The parameters are contained in the application data of the packet. USO state: On (1), Off (0)
6.1.1.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware.
6.1.1.2.4.1 Action Taken
Bit 13 of address 100 of the control register is set to the value specified.
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6.1.1.2.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. The direct effect of this is that the USO is turned on or off. The USO is temperature stabilized. It has two sensors-TLM Heating and TLM RF. The first is a measure of the temperature stabilizing circuit operation, the second is a measure of the output power. These two indicators are not calibrated. The supply voltage and current also change. The typical effect on telemetry is summarized below.
USO Power Telecommand Off On
Control Bits
AddReg 100, Bit 13 (NMRA0005, bit 10) 0 1
Sensor Results
TLM Heating (NMRA0027) 0.01 1.35
TLM RF (NMRA0028) 0.01 0.05
+24V (NMRA0020) 23.37 23.5
+24V Current (NMR0026) 0.02A 0.4A
Impact on the science data: The frequency calibration of the spectroscopic data will be correct. There is no way of verifying this from the data other than looking at a source with a known spectroscopic signature, such as an astrophysical source.
6.1.1.2.4.3 Additional Information
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to 0.
6.1.1.2.5 RSDB Inputs
Telecommand: ZMR19209 -USO Power
Parameters: PMRG0015 -PLL Reset, default 0, Off
CMRV0005 0, off 1, on
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6.1.1.3 CTS Warm Up Telecommand
6.1.1.3.1 Description
The analog part (SAW filters) of the CTS is temperature controlled. For optimum performance of the thermal feedback analog part of the CTS should be at least 20 C above ambient. This command turns on the thermal control. It takes about an hour for the CTS to stabilize.
In addition, the CTS does not turn on correctly if it is below about -5 C. Therefore it needs to be warmed up prior to turning it on. It warms up in a few minutes after executing this command.
This command can be executed in any non-spectroscopic mode. In a spectroscopic mode the CTS heater command should be used to change the temperature for the thermal control.
6.1.1.3.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010011 EID-A Optional, 19 = CTS Warm up
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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CTS Warm Up Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
CTS Heater Power 4 0=High, 1=Off, 2=Low
CTS Heater Temperature 4 All values are degrees C; 0=0, 1=10, 2=20, 3=30, 4=40, 5=50, 6=60, 7=70
Reserved 8 Not Used
6.1.1.3.3 Parameters
The parameters are contained in the application data of the packet.
CTS Heater Temperature (PMRD2701): 0, 10, 20, 30, 40, 50, 60, 70
CTS Heater Power (PMRD2702): High, Off, Low
6.1.1.3.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore to tell the memory check task to perform the CTS warm up processing.
6.1.1.3.4.1 Action Taken
The memory check task powers on the CTS and sets the analog SAW filter temperature and power levels as specified in the TC. The CTS internal clocks are then turned off to reduce power consumption. The CTS digital electronics remain on. The global variable that contains the CTS temperature and power level is also set as specified by the TC.
6.1.1.3.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. The direct effect of this is that the thermal control for the analog SAW filters of the CTS is turned on and set to the input temperature. The heating rate is determined by the power level. There are 6 temperature sensors in the CTS. Spect Temp 1-4 are in the analog part. Spect Temp 5-6 are in the digital part. The first four temperatures should stabilize at the commanded temperatures. The last 2 temperatures will increase by about 5-10 C. The supply voltage and current also change. The typical effect on telemetry is summarized below.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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CTS Warm Up Telecommand Off On
Control Bits
Add Reg 100, bit 9 (NMRA0005, bit 14) 0 1
Add Reg 100, bit 11 (NMRA0005, bit 12) 0 1
Add Reg 100, bit 10 (NMRA0005, bit 13) 0 1
Add Reg 100, bit 8 (NMRA0005, bit 15) 0 1
Add Reg 100, bit 12 (NMRA0005, bit 11) 0 1
Add Reg 100, bit 15 (NMRA0005, bit 8) 0 1
Sensor Results
Spect Temp #1 (analog) (NMRA0009) ambient commanded temperature
Spect Temp #2 (analog) (NMRA0010) ambient commanded temperature
Spect Temp #3 (analog) (NMRA0011) ambient commanded temperature
Spect Temp #4 (analog) (NMRA 0012) ambient commanded temperature
Spect Temp #5 (digital) (NMRA0013) ambient ambient + 5 C
Spect Temp #6 (digital) (NMRA0014) ambient ambient + 5 C
+12V EU (NMRA0016) 13.20V 12.29V
+12V Curr EU (NMRA0022) 0.07A 0.31A
Impact on the science data: There is no easily measured impact on the science data. The CTS spectroscopic data will be more stable when the CTS SAW filters are maintained at a constant temperature.
6.1.1.3.4.3 Additional Information
When the CTS is warming up great care must be taken to not perform a mode change to a mode where the CTS is not normally on because the CTS will then be powered off and the benefit of the warm up will be reduced.
The default setting of the global variable that contains the CTS temperature and power level is 30 C and low power. The default setting of the global variable takes place when either the instrument is powered on or a software restart TC is processed. The setting of the CTS heater temperature and power level in the CTS itself does not take place until the CTS is turned on. In the case where this TC is used to warm up the CTS and also to set the CTS temperature and power global variable, that setting will remain in memory even when the instrument is put into a mode where the CTS is powered off. Upon entering a mode where the CTS is again powered on the global variable will be used to set the CTS temperature and power level to the previous setting.
Once the CTS warm up command has been issued there is no way "turn off" the warming up process other than performing a mode change to a mode where the CTS is not on. The "CTS Heater Power" data element described above when set to off does not turn the CTS warm up off it sets the heater power to the analog SAW filter heaters off. The CTS digital electronics remain powered.
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Thermal-Vacuum testing of the CTS has shown that at temperatures around -5 C and below the CTS electronics need to be warmed up for a period of a few minutes to insure that the internal calibration of the CTS sum of squares table is performed correctly. Failing to warm up for a sufficient period of time, or simply switching to a CTS operational mode without warming up, could result in incorrectly calibrated CTS sum of squares tables. This will be evident in the CTS table midpoint values in the miscellaneous science TM packet. Nominal values for the CTS table midpoints fall within the range of 122-128. In the failure case the midpoints exceed 128 and are often in the area of 38000 and higher.
6.1.1.3.5 RSDB Inputs
Telecommand: ZMR19221 - CTS Warm up
Parameters: PMRD2701 - CTS Heater Temperature
CMRV0016 0, 0 deg 1, 10 deg 2, 20 deg 3, 30 deg 4, 40 deg 5, 50 deg 6, 60 deg 7, 70 deg
PMRD2702 - CTS Heater Power
CMRV0017 0, High Power 1, Off 2, Low Power
PMRD2703 - Not Used
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6.1.2 MODE CHANGE TELECOMMANDS
6.1.2.1 Mode Change Telecommand
6.1.2.1.1 Description
MIRO has six primary modes:
1.
Engineering mode
2.
Millimeter-wave continuum mode
3.
Submillimeter-wave continuum mode
4.
Dual continuum mode
5.
CTS/submillimeter-wave continuum mode
6.
CTS/dual continuum mode
The Engineering mode is the lowest power mode. The flight computer is turned on and returns the engineering telemetry.
The continuum modes include the millimeter-wave continuum mode, the submillimeter-wave continuum mode and the dual continuum mode. In the millimeter-wave continuum mode only the millimeter-wave receiver is on and returning data. Similarly, in the submillimeter-wave continuum mode only the submillimeter-wave continuum receiver is on and returning data. In the dual continuum mode both the submillimeter-wave and millimeter-wave continuum receivers are on and returning data.
The spectroscopic modes include the CTS/submillimeter-wave continuum mode and the CTS/dual continuum mode. The submillimeter-wave receiver can return both continuum and spectroscopic data. To return spectroscopic data requires that the USO be on, the submillimeter-wave local oscillator be phase locked, and the intermediate frequency processor be operational, as well as the continuum parts of the receiver be on. The CTS/submillimeter-wave continuum mode returns both submillimeter-wave spectroscopic and continuum data. The CTS/dual continuum mode returns submillimeter-wave spectroscopic data, submillimeter-wave continuum data, and millimeter-wave continuum data.
The sequence followed for the continuum modes starts with a calibration that consists of (1) observing the "hot" load for 30 seconds, (2) observing the "cold" load for 30 seconds, (3) observing the "source" for 30 seconds, and (4) continuing to observe "source" position. This sequence is repeated every 33 minutes and 50 seconds. The data is returned as counts.
The sequence followed for the spectroscopic modes starts with (1) observing the "hot" load for 30 seconds with the frequency switching between LO 0 and LO 1 every 5 sec, (2) observing the "cold" load for 30 seconds with the frequency switching between LO 0 and LO 1 every 5 seconds, (3) observing the "source" position for 30 seconds with the frequency switching between LO 0 and LO 1 every 5 seconds, and (4) repeated "source" position observations for the integration time with the frequency switching between LO 0 and LO 1 every
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5 seconds. LO 1 shifts frequencies +5MHz (higher frequency). LO 0 shifts frequency -5MHz (lower frequency). This continues for 33 minutes and 50 seconds, when the sequence starts over. The calibration data is returned as 15 seconds of added data binned into LO 0 and LO 1 data sets, while the signal is returned as [LO 0 (-5MHz) - LO 1 (+5MHz)].
In addition to changing the mode, the parameters that control data volume associated with each mode are passed by this telecommand. Additional settings associated with each mode have separate telecommands given later.
6.1.2.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00000101 EID-A Optional, 5 = Mode Change
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Mode Change Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Power mode 3 1=CTS/Dual Continuum, 2=CTS/SMM Continuum, 3=Dual Continuum, 4=SMM Continuum, 5=MM Continuum, 6=Engineering
CTS integration period 2 0=30 sec, 1=60 sec, 2=90 sec, 3=120 sec
Continuum summing value 3 0=sum 1, 1=sum 2, 2=sum 5, 3=sum 10, 4=sum 20
CTS smoothing value 2 0=smooth 1, 1=smooth 2, 2=smooth 3, 3=smooth 4
Reserved 1 Not used
Reserved 1 Not used
Reserved 4 Not Used
6.1.2.1.3 Parameters
The parameters are contained in the application data of the packet.
Power mode: selects one of six power modes. The instrument is in engineering mode when powered on.
CTS integration period: selects one of four integration periods for the submillimeter-wave spectroscopic data. 30 seconds is the default. This parameter is set greater than the default in order to reduce data volume for a given period of time. When this parameter is set to 120 seconds, for instance, four 30-second data sets are averaged together on-board. This does not affect the continuum data.
Continuum summing value: This selects the number of continuum data sets to add together on-board. The default is to sum 1 data set. This parameter is set greater than the default in order to reduce data volume for a given period of time. When this parameter is set to sum 10, for instance, 10 continuum values are added together on board. Note that the data is summed, not averaged. This is applied to the millimeter-wave and/or submillimeter-wave continuum data. This does not affect the spectroscopic data.
CTS smoothing value: This parameter smoothes the spectroscopic data in frequency. The default value is "smooth 1" which returns all 4096 of the CTS channels. This parameter is set greater than the default in order to reduce data volume for a given period of time. "Smooth 2", for instance, reduces the number of CTS channels by a factor of 2, from 4096 to 2048.
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6.1.2.1.4 Execution Description
The inbound FIFO manager task parses the information contained in the mode change TC and stores it in global memory for use by the executive task. The inbound FIFO manager task then sets the mode_change semaphore to notify the executive task that a mode change has been commanded.
The executive task checks for a mode change once per second while in the nominal processing loop.
6.1.2.1.4.1 Action Taken
Upon detection of a mode change command the executive task begins a graceful shutdown of the software in the current mode of operation. If running in a mode where the CTS is operating the current CTS integration is allowed to complete. If we are running in one of the continuum modes the current 5 seconds (100 samples) of continuum data collection is allowed to complete. In both of these cases all collected science TM data is processed and flushed out to the outbound FIFO manager task as part of the graceful shutdown.
Following the graceful shutdown the executive task sets all required global variables to control the transition to the new operating mode. Any required powering off/on of the various hardware components is then performed. The software then enters the new operating mode and an instrument calibration is performed provided the new mode is anything other than engineering mode. If the CTS has been powered on as part of the new mode then the instrument calibration is preceded by an internal CTS calibration.
6.1.2.1.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data.
The software will enter the new operating mode following a graceful shutdown of the previous mode. New telemetry output rates and power consumption will be in effect depending on the operational mode that is entered.
The typical effect on address register 100 and SUCR is summarized below. Values for temperatures, voltages and currents can be found in Section 7.1.2.3 Expected Values for engineering telemetry.
The result on the science data: Typical science data are given in Section 7.1 as follows:
*
Section 7.1.3 Spectroscopic (CTS) Science Telemetry (YMR00011)
*
Section 7.1.4 Submillimeter Continuum Science Telemetry (YMR00011)
*
Section 7.1.5 Millimeter Continuum Science Telemetry (YMR00011)
*
Section 7.1.6 Miscellaneous Science Telemetry (YMR00011)
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Function Telemetry Eng. mm cont smm cont. Dual cont CTS/SMM CTS/Dual
Operational Mode (Power Mode) NMRA0002 (NMRD0201) 6 5 4 3 2 1
Operational Mode (CTS Integration Period) NMRA0002 (NMRD0202) NA NA NA NA 0=30s, 1=60s, 2=90s, 3=120s 0=30s, 1=60s, 2=90s, 3=120s
Operational Mode (Continuum Sum Value)) NMRA0002 (NMRD0203) NA 0=sum 1 1=sum 2 2=sum 5 3=sum10 4=sum20 0=sum 1 1=sum 2 2=sum 5 3=sum10 4=sum20 0=sum 1 1=sum 2 2=sum 5 3=sum10 4=sum20 0=sum 1 1=sum 2 2=sum 5 3=sum10 4=sum20 0=sum 1 1=sum 2 2=sum 5 3=sum10 4=sum20
Operational Mode (CTS Smoothing Value) NMRA0002 (NMRD0204) NA 0=sm 1 1=sm 2 2=sm 3 3=sm 4 0=sm 1 1=sm 2 2=sm 3 3=sm 4
-5V SBEU for mm cont. SUCR bit 25 (NMRA0004, bit 6) 0 1 0 1 0 1
-5V SBEU for smm cont SUCR bit 24 (NMRA0004, bit 7) 0 0 1 1 1 1
-5V SBEU for spectroscopy SUCR bit 26 (NMRA0004, bit 5) 0 0 0 0 1 1
+5V SBEU, +/-12V SBEU for mm cont. SUCR bit 10 (NMRA0003, bit 5) 0 1 0 1 0 1
+5V SBEU, +/-12V SU for smm cont. SUCR bit 5 (NMRA0003, bit 10) 0 0 1 1 1 1
+5V SBEU, +/-12V SBEU for spect. SUCR bit 11 (NMRA0003, bit 4) 0 0 0 0 1 1
+12V SPEC EU Add Reg 100, bit 8 (NMRA0005, bit 15) 0 0 0 0 1 1
+5V Spec EU Add Reg 100, bit 9 (NMRA0005, bit 14) 0 0 0 0 1 1
+5V ANA SPEC EU Add Reg 100, bit 10 (NMRA0005, bit 13) 0 0 0 0 1 1
+3.V SPEC EU Add Reg 100,bit 11 (NMRA0005, bit 12) 0 0 0 0 1 1
-12V SPEC EU Add Reg 100,bit 12 (NMRA0005, bit 11) 0 0 0 0 1 1
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For the spectroscopic modes the CTS sum-of-squares table midpoints will be placed in the miscellaneous science file. This is one of the earliest diagnostics to determine if the CTS is operating correctly. The CTS warm up telecommand should be executed prior to the change mode command if its operating temperature is below about -5C. If the CTS is operating correctly, the midpoints of the sum-of-squares tables will all be about 125. If is not, then one or more midpoints is zero.
The frequency smoothing is accomplished as described below.
Smoothing Shift = 1: All 4096 values are returned.
4096
Smoothing Shift = 2: Window size of 5 is shifted over data set 2 positions at a time. Returned value is computed as a mathematical weighting function of the 5 values in the window. The smoothing weights are 0.03, 0.22, 0.50, 0.22, 0.03, respectively. 2046 values are returned.
4096
Smoothing Shift = 3: Window size of 7 is shifted over the data set 3 positions at a time. Returned value is computed as a mathematical weighting function of the 7 values in the window. The smoothing weights are 0.01, 0.03, 0.30, 0.32, 0.30, 0.03, 0.01, respectively. 1364 values are returned.
4096
1 2 3 4 5 6 7 8 9 10 11 12 13
1 -7 Returned Value 2
4 - 10 Returned Value 3 7 - 13
Smoothing Shift = 4: Window size of 9 is shifted over the data set 4 positions at a time. Returned value is computed as a mathematical weighting function of the 9 values in the window. The smoothing weights are 0.01, 0.03, 0.11, 0.23, 0.24, 0.23, 0.11, 0.03, 0.01, respectively.1022 values are returned.
4096
1 2 3 4 5 6 7 8 9 10 11 12 13
1 -9 Returned Value 2 5 - 13 Returned Value 3 Returned Value 1
9 - 17
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6.1.2.1.4.3 Additional Information
The executive assembly only processes mode change commands during the nominal processing loop. This means that any mode changes sent to the software during instrument calibration will not be acted upon until after the instrument calibration is complete. For example, if the instrument is running in engineering mode and is then commanded into CTS/dual continuum mode the following will take place. The numerous hardware components will be powered on, the CTS internal sum of squares table will be initialized, and an instrument calibration will be performed. This requires approximately 2.5 minutes. During that 2.5 minutes, the executive assembly is not checking for any further mode change commands. The first CTS integration is started, and then the executive assembly enters the nominal processing loop where mode change commands are processed. Any mode change sent in during the prior 2.5 minutes will then be acted upon. Assuming a mode change was sent to the instrument during that time, a graceful shutdown will allow for at a minimum of 1 CTS integration period to complete, which could require anywhere from an additional 30-120 seconds depending on the CTS integration period. In the case where multiple mode change commands are sent to the instrument during the instrument calibration, only the last one received is processed. Mode change commands are not kept in a buffer, only the last one received is processed.
6.1.2.1.5 RSDB Inputs
Telecommand: ZMR19214 - Mode Change
Parameters: PMRD2001 - Power Mode, default = Engineering
CMRV0012 1, CTS/Dual Cntm 2, CTS/SMMCntm 3, DualContinm 4, SMMContinuum 5, MM Continuum 6, Engineering
PMRD2002 - CTS Integration Period, default = 30 s
CMRV0013 0, 30 sec 1, 60 sec 2, 90 sec 3, 120 sec
PMRD2003 - Continuum Sum Value, default = Sum 1
CMRV0014 0, Sum 1 1, Sum 2 2, Sum 5 3, Sum 10 4, Sum 20
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PMRD2004 - CTS Smoothing Value, default =Smooth 1
CMRV0015 0, Smooth 1 1, Smooth 2 2, Smooth 3 3, Smooth 4
PMRD2005 - Reserved
PMRD2006 - Reserved
PMRD2007 - Reserved
6.1.2.2 Asteroid Mode Telecommand
6.1.2.2.1 Description
The asteroid mode telecommand is a complex command calling the other modes in a timed sequence. Asteroid Mode returns "raw" data, the only mode that does so.
TIME LINE FOR ASTEROID MODE
All times will be referenced to the Start Time in the Asteroid Mode command, which is when data in asteroid mode start to be generated. The time when the spacecraft is at closest approach to the asteroid is called the "asteroid flyby time". Prior to this time the spacecraft is approaching the asteroid, after it the spacecraft is leaving the asteroid. At the asteroid flyby time the relative velocity between the spacecraft and the asteroid is zero.
The maximum time for this whole procedure to take place, starting two hours prior to the start time, is about 6 hrs in the longest case. It is a function of the Execution time parameter, N, as follows:
* Time to complete=3.1+0.03*N (hours).
At this point, all the data taken in asteroid mode will have been played out. However, the data taken in CTS/Dual mode during the playback period will only be beginning to be played out. The choice must then be made whether to switch the instrument off and lose these latter data or wait until the playback has "caught up", which will take many more hours.
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Time Name Type Event
-2 hour (at least) manual MIRO instrument turned on and warmed up (USO on, Cal Heater on, CTS warm up 70C/High)
-7 min (at least) manual Execute Asteroid mode command
-(4 min + CTS integration time) (at least) manual Execute Change Mode to Dual Continuum Mode
-119 sec Carried out automatically by asteroid command 1. graceful shutdown, 2. power up for asteroid mode, 3. CTS internal calibration, 4. SMM Gunn voltage auto scan
0 Start time Carried out automatically by asteroid command Start calibration
133.5 sec Carried out automatically by asteroid command Start taking N data sets with LO frequency in starting "LO frequency setting"
133.5+N*5.26 sec [10.7 minutes max] Asteroid flyby time Carried out automatically by asteroid command LO setting switched, take N data sets
133.5+N*10.52 sec [19 minutes max] Carried out automatically by asteroid command Start calibration
267+N*10.52 sec [21.3 minutes max] Carried out automatically by asteroid command change mode to Dual continuum mode
387+N*10.52 sec manual change mode to CTS/Dual Continuum to maximize data playback rate (NOTE: if data taken in this mode are of value, precede this with a CTS warm up command!)
67+1.8*N minutes (approx.) Playback end manual All asteroid data read out. Execute change mode to Engineering
LO SETTING
The LO setting is optimized for the H2O line. The frequency of the water line (and all the other lines) is Doppler shifted due to the relative motion of the spacecraft and the source of emission (the asteroid). It moves from high frequency (approaching the asteroid) to low frequency (departing from the asteroid). However the direction that this frequency shifts in the MIRO spectrometer depends on which sideband the line is in for each of its downconversions. This varies with each line as shown in the table below.
LO 1 shifts frequencies - 5MHz (lower frequency). LO 0 shifts frequency +5MHz (higher frequency).
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Line Initial LO Setting Frequency Shift in Spectrometer on Approach Frequency Shift in Spectrometer on Departure SpectrometerFrequency with no Shift (MHz)
H216O 1 - + 1270
H217O 1 - + 1300
CH3OH 0 + - 1320
H218O 1 - + 1340
CO 1 - + 1363
CH3OH 1 - + 1389
NH3 0 + - 1407
CH3OH 1 - + 1425
6.1.2.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000001101 This gets set to the size of the application data field (in bytes) + 5. In this case, 13.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001111 EID-A Optional, 15 = Asteroid mode
Pad 8 00000000 EID-A Mandatory
Application Data 64 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
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Asteroid Mode Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Start Time 32 Variable Spacecraft time in seconds
Execution Time 16 Variable Number of 5-second CTS scans per LO frequency. Must be an even number between 2 and 96.
Starting LO frequency 16 0 or 1 LO frequency to start on, switch to other as per science FR document
6.1.2.2.3 Parameters
The parameters are contained in the application data of the packet.
Start time (PMRG2501 Astrd Mode #1) (= asteroid flyby time - (N*5.3+139)[sec])
Start Time is the time at which the asteroid mode begins its automated sequence. This should precede the Asteroid Flyby time by an interval equal to the Execution Time parameter multiplied by 5.3 seconds plus the time for a calibration (139 secs). Start Time must be at least 8 minutes later than the time at which the Asteroid Mode command is issued. The units of Start Time are spacecraft time in seconds.
Execution time (PMRD2502) (N, = even number between 2 and 96)
Execution Time is the number of 5-second CTS scans per LO frequency that are done before and after the encounter. This value must be an even integer between 2 and 96.
Starting LO Frequency (PMRD2503) (= 0 or 1)
For CTS warm up command
CTS Heater Temperature (PMRD2701) (= 0, 10, ... 50, 60, 70 deg)
CTS Heater Power (PMRD2703) (= High or Low)
For Dual continuum time (= Execution time (PMRD2502)*.37 hours)
Dual Continuum Observation Time is the time to read out the data taken during the asteroid encounter. Data continues to be taken in Dual Continuum mode, after the asteroid mode sequence has been completed.
6.1.2.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task checks to verify that the start time of the asteroid mode is at a minimum of 130 seconds in the future. If that is the case then a global variable is set to notify the executive task that asteroid mode has been programmed. (Note that 130 seconds is an absolute lower limit; in practice the interval should be considerably longer, see Timeline, above.)
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6.1.2.2.4.1 Action Taken
Once notified that asteroid mode is programmed the executive task begins checking once per second if it is time to begin asteroid mode processing by performing a graceful software shutdown of the current operational mode. Once the graceful shutdown has been completed the powering up for asteroid mode is done. An internal CTS table calibration is performed and the SMM Gunn Voltage setting is found using the nominal search described earlier. The asteroid mode routine is called by the executive task and all high level control over asteroid mode processing is done there.
6.1.2.2.4.2 Resulting Effect
The programmed asteroid mode sequence is executed at the time specified in the asteroid mode command.
The asteroid mode doesn't do anything until about 2 minutes prior to the start time except check to see if it is time to start its automated sequence. At about 2 minutes prior to the start time the instrument should be in dual continuum mode and fully warmed up.
The effect of the asteroid mode command will be to place MIRO in CTS/Dual Continuum mode about 2 minutes prior to the Start Time, calibrate the instrument, take a number (N) of CTS scans with the LO set at its initial frequency, change to the other LO setting and take another N scans, calibrate again and then to return automatically to Dual Continuum mode.
To verify that the asteroid mode has been activated check the asteroid mode programmed and asteroid mode start time parameters in the Miscellaneous file.
In addition, progress event reports are generated.
*
Asteroid Mode Started (YMR00013) is generated when the flight software begins running the asteroid mode sequence. This should correlate to the asteroid mode start time issued in the asteroid mode TC.
*
Asteroid Mode Completed (YMR00014) is generated when the flight software completes the asteroid mode sequence.
6.1.2.2.4.3 Additional Information
Running in asteroid mode generates a large amount of CTS data that are internally buffered in the instrument. These data are played back in the mode selected following asteroid mode, during which time the instrument will be taking more data in that mode. It can take as long as 35 hours for the playback to catch up to the data being acquired. If the instrument is powered down, or a software restart is performed, or disable science telemetry command is executed for any reason all accumulated data that is buffered internally will be lost.
The instrument can be in any mode when the command is sent to program asteroid mode. However, to transition to asteroid mode correctly the instrument must be in dual continuum mode at the time that the graceful shutdown is
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performed prior to starting asteroid mode. This time is approximately 120 seconds prior to the programmed asteroid mode start time.
During initial software startup following power on or during a software restart to incorporate memory patches there is no asteroid mode programmed by default.
6.1.2.2.5 RSDB Inputs
Telecommand: ZMR19219 - Asteroid Mode Parameters: PMRG2501 - Astrd Mode#1 (Start Time) PMRG2502 - Astrd Mode#2 PMRD2502 - Execution Time PMRD2503 - Starting LO Frequency CMRV0019 0, LO Freq 0 1, LO Freq 1
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6.1.3 ADDITIONAL ENGINEERING MODE TELECOMMANDS
6.1.3.1 Engineering Housekeeping Cycle Skip Telecommand
6.1.3.1.1 Description
The digital noise generated when reading the engineering housekeeping data every 11 seconds can cause excess noise in the continuum data. The engineering housekeeping cycle skip command can be used to skip this readout for a certain period of time in order to eliminate this noise source.
6.1.3.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010110 EID-A Optional, 22 = Engineering HK Cycle Skip
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Number of 11.2 second engineering cycles to skip data collection. Range of 0-65535.
Packet Error Control 16 Variable Telecommand Packet Checksum
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6.1.3.1.3 Parameters
The parameters are contained in the application data of the packet.
N = number of 11.2 sec engineering data packets to skip reading. N = 0 is the default.
6.1.3.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately sets the global variable used to control the processing of the engineering data collection task.
6.1.3.1.4.1 Action Taken
The engineering data collection task uses the global variable to determine how many 11.2-second engineering data collection cycles should be skipped following each cycle in which data is collected.
6.1.3.1.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data.
In the telemetry: NMRAH143 MR71/4 DataFieldHdr time - successive values differ by (N+1)*11.2 seconds.
The impact on the science: When set to a value other than 0, the engineering data collection task will not perform any A/D conversions of engineering data during the specified number of 11.2-second engineering collection cycles. No engineering HK packets will be generated during those cycles as a result. The continuum data, if we are running in a mode where it is being collected, will be more stable during the cycles of non-collection as opposed to when sensor unit A/D conversions are taking place.
6.1.3.1.4.3 Additional Information
This TC was added solely for the purpose of allowing the ground controllers the option to "turn off" engineering data collection for specific periods of time to collect cleaner continuum data. The TC to turn off engineering HK packet generation would not produce the same result, as that TC simply causes the software to drop collected packets on the floor, while the A/D conversions that cause the noise in the continuum channels continue. Upon initial power-on or a software restart the default setting for this value is zero, indicating that no collection cycles will be skipped. This is the nominal mode where engineering HK TM packets get generated every 11.2 seconds. Any changes made to the skip value will not be reflected until the following 11.2-second collection cycle. For example, if sometime after instrument power-on the TC was sent with a skip value of 10, the current 11.2-second cycle of collection would be completed prior
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to the engineering task then skipping the subsequent 10 collection cycles. While in the process of skipping the 10 cycles it is possible to increase the number of cycles to skip by sending another TC with a value greater than 10. If a TC were then sent to skip 20 cycles while the software was halfway through skipping 10 cycles the total number of cycles ultimately skipped would be exactly 20. There is no cumulative/additive effect. When the software finishes skipping the desired number of cycles it repeats the entire sequence again by collecting engineering data for 1 cycle and then skipping the desired number of cycles. This repeats indefinitely, until the cycle skip count is again changed by TC.
Lowering the skip count value from a higher value has 2 possible outcomes. If the new skip count value is higher than the number of cycles that have already been skipped then the software will simply keep skipping cycles until the new lower number of cycles has been skipped. If the new skip count value is lower than the number of cycles that have already been skipped then the next cycle that starts will be a good collection cycle followed by the new number of skipped cycles.
For purposes of simply "turning off" engineering data collection for an indefinite period the best method would be to uplink this TC with a value of 65535. This will produce a skip period of 8.5 days, effectively turning off engineering data collection. When one wants to resume periodic engineering HK data collection just send the TC in with a more reasonable skip count value (i.e., 5) or just a zero to cause it to collect engineering HK data continuously.
6.1.3.1.5 RSDB Inputs
Telecommand: ZMR19224 - Engineering Housekeeping Cycle Skip
Parameters: PMRG0030 -Eng HK Cycles Skip
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6.1.4 ADDITIONAL CONTINUUM MODE TELECOMMANDS
6.1.4.1 Continuum Subtraction Value Telecommand
6.1.4.1.1 Description
The maximum value for continuum data, 32000, may be exceeding when looking at a very bright source or using the continuum summing capability in the mode change telecommand. When this happens, data is lost. Typical values for un-summed continuum data are about 7000. The continuum subtraction value telecommand allows the subtraction of an offset prior to summing to mitigate this problem. Different values can be entered for the millimeter-wave and submillimeter-wave continuum channels.
6.1.4.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000001001 This gets set to the size of the application data field (in bytes) + 5. In this case, 9.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001110 EID-A Optional, 14 = Continuum subtraction
Pad 8 00000000 EID-A Mandatory
Application Data 32 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
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Continuum Subtraction Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Millimeter Subtraction Value 16 Variable Unsigned integer to be subtracted from each millimeter sample.
Submillimeter Subtraction Value 16 Variable Unsigned integer to be subtracted from each submillimeter sample.
6.1.4.1.3 Parameters
The parameters are in the application data.
*
Millimeter-wave subtraction value: integer to be subtracted from the millimeter-wave continuum data.
*
Submillimeter-wave subtraction values: integer to be subtracted from the submillimeter-wave continuum data.
6.1.4.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a global variable that is used by the continuum interrupt processing task.
6.1.4.1.4.1 Action Taken
The continuum interrupt processing task uses the two subtraction values supplied to decrement the raw continuum samples taken every 50 milliseconds.
6.1.4.1.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data.
No effect on the command address registers or the engineering sensors.
The impact on the science data:
1.
The value of the millimeter-wave and submillimeter-wave continuum subtraction values are stored in the header of the continuum data files as well as in the Miscellaneous Science File.
2.
The summed continuum samples that get output in the TM packets will be reduced.
6.1.4.1.4.3 Additional Information
The continuum subtraction takes place prior to any other processing of the continuum data. Raw continuum samples are collected every 50 milliseconds and the continuum subtraction value is decremented from the raw samples. Only after this decrementing is the summing of the continuum samples performed as per the current continuum summing value specified in the operational mode. The
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continuum subtraction value is placed in the continuum TM packet to allow for easier decoding of the data. The continuum subtraction value is placed in the TM packet at the time of packet creation and will not reflect the continuum subtraction value later on in the TM packet if the subtraction value is changed during the course of populating the continuum TM packet. A continuum packet can take anywhere from 10 to 200 seconds to fill depending on the continuum summing value in effect. During initial software startup following power on or during a software restart to incorporate memory patches the continuum subtraction values are set to zero.
6.1.4.1.5 RSDB Inputs
Telecommand: ZMR19218 Continuum Subtraction Value
Parameters: PMRD2401 - MM Subtraction Value, default =0
PMRD2402 - SMM Subtraction Value, default=0
6.1.4.2 Millimeter LNA Power Telecommand
6.1.4.2.1 Description
This command turns the power on or off to the millimeter-wave receiver low noise amplifier on the optical bench. The power is turned off in order to obtain a "zero" value for the millimeter-wave continuum data calibration. This should be done at least once per millimeter-wave continuum, dual continuum, or CTS/dual mode observing session.
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6.1.4.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00000111 EID-A Optional, 7 = MM LNA Power
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-1 decimal: 0=Power Off, 1=Power On
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.4.2.3 Parameters
The parameters are given in the packet application data. mm LNA power state (PMRG0009) : Power off=0, Power on = 1
6.1.4.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware.
6.1.4.2.4.1 Action Taken
Bit 8 of address 700 of the sensor unit control register is set to the opposite of the value specified. In the hardware 0=on and 1=off.
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6.1.4.2.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. Typical values are given below.
mm LNA Power Telecommand Off On
Control Bits
SUCR, Bit 8 (NMRA0003, bit 7)** 1 0
Sensor Results
+12V-2 Current SBEU*(NMRA0054) 0.56A 0.7A
*The difference of roughly 0.014A should be observed. The absolute value depends on the rest of the state of the instrument **Note that the value of the SUCR Bit 8 has the inverse meaning of the command value.
The impact on the science data: The mm-wave continuum value goes to its "zero" counts level, about 1700.
6.1.4.2.4.3 Additional Information
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to on (0 in the SUCR).
6.1.4.2.5 RSDB Inputs
Telecommand: ZMR19203-MM LNA Power
Parameters: PMRG0009-mm LNA Power, default 1, On
CMRV0005 0, off 1, on
6.1.4.3 Submillimeter LNA Power Telecommand Definition
6.1.4.3.1 Description
This command turns the power on or off to the submillimeter-wave receiver low noise amplifier on the optical bench. The power is turned off in order to obtain a "zero" value for the submillimeter-wave continuum data calibration. This should be done at least once per submillimeter-wave continuum, dual continuum, or CTS/dual mode observing session.
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6.1.4.3.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001000 EID-A Optional, 8 = SMM LNA Power
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-1 decimal: 0=Power Off, 1=Power On
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.4.3.3 Parameters
The parameters are given in the packet application data. smm LNA power state (PMRG0010): Power off = 0, Power on = 1 Upon receipt of this TC the inbound FIFO manager task immediately clocks the
specified setting out to the hardware.
6.1.4.3.3.1 Action Taken
Bit 9 of address 700 of the sensor unit control register is set to the opposite of the value specified. In the hardware 0 = on and 1 = off.
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6.1.4.3.3.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. Typical values are given below.
smm LNA Power Telecommand Off On
Control Bits
SUCR, Bit 9 (NMRA0003, bit 6)** 1 0
Sensor Results
+12V-2 Current SBEU*(NMRA0054) 0.56A 0.7A
*The difference of roughly 0.014A should be observed. The absolute value depends on the rest of the state of the instrument
** Note that the value of the SUCR Bit 9 has the inverse meaning of the command value.
Impact on the science data: The submm-wave continuum level goes to its "zero" level, about 1700.
6.1.4.3.3.3 Additional Information
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to on (0 in the SUCR).
6.1.4.3.4 RSDB Inputs
Telecommand: ZMR19204 -Submm LNA Power
Parameters: PMRG0010 -Submm LNA Power, default 1, On
CMRV0005 0, off 1, on
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5 ADDITIONAL SPECTROSCOPIC MODE TELECOMMANDS
6.1.5.1 IFP Power Control Telecommand
6.1.5.1.1 Description
This telecommand sets the power level into the chirp transform spectrometer (CTS) coming out of the intermediate frequency processor (IFP). It can be adjusted in 1dB steps over a range of 16 dB. The power level for the hot mirror position during a calibration should be about 20000. This is a function of temperature since the gain of the system varies with temperature. At room temperature this is achieved with an IFP power setting of 3 dB.
Since this command changes the gain of the spectroscopic system a calibration sequence is automatically initiated when it is executed.
6.1.5.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00000100 EID-A Optional, 4 = IFP Power Control
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-15 decimal, specifies the IFP Power Control
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.1.3 Parameters
The parameters are given in the packet application data.
IFP power level (PMRG0011): 0 = 0 dB, 1 = -1 dB, 2 = -2db ... .15 = -15dB
6.1.5.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task stores the setting in a global memory location. If the instrument is already running in a mode where the CTS is powered on the executive task initiates a mode change.
6.1.5.1.4.1 Action Taken
The executive task initiates a graceful shutdown of the software as part of a nominal mode change. Prior to performing an instrument calibration the IFP Power Control setting that was stored in global memory is clocked out to the hardware. Bits 6-7 and 13-14 of address 700 of the sensor unit control register are set to the value specified.
6.1.5.1.4.2 Resulting Effect
The resulting effect has three parts: 1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits,
2) the change in temperature, voltage, etc. as measured by sensors, and 3) impact on the science data. Typical values are given below.
IFP Power Control Telecommand
Control Bits
SUCR, Bit 6 (NMRA0003, bit 9) Bit 0 of IFP Power Control
SUCR, Bit 7 (NMRA0003, bit 8) Bit 1 of IFP Power Control
SUCR, Bit 13 (NMRA0003, bit 2) Bit 2 of IFP Power Control
SUCR, Bit 14 (NMRA0003, bit 1) Bit 3 of IFP Power Control
Sensor Results
NA
Impact on the science: Typical CTS spectra in the hot mirror position during the calibration sequence as a function of IFP Power Control values is given in the table below.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Value Commanded IFP Level Observed CTS Level Measured Ratio to IFP Level =0 Ratio if Exactly 1 dB Change
3 -3db 19633
0 0dB 36531 1 1
1 -1dB 31393 0.86 0.79
2 -2dB 24010 0.66 0.66
4 -4dB 15738 0.43 0.42
8 -8dB 5203 0.14 0.14
3 -3dB 19520 0.53 0.50
6.1.5.1.4.3 Additional Information
The effect of the changing of the IFP Power Control is so great on the CTS data it was decided to have this command treated as if it were a mode change command. A graceful software shutdown is performed prior to implementing the new setting.
The IFP bits in the sensor unit control register are not tri-stated. When the CTS is not on these bits need to be set to 0. When the CTS is on, the global variable containing the IFP power level setting is clocked into the hardware shortly after the CTS is powered on. The powering on and off of the 4 IFP bits is now done in the power_off and power_on routines.
During initial software startup following power on or during a software restart to incorporate memory patches the global value is set to 3. The hardware is set to 0 because we come up in engineering mode by default.
6.1.5.1.5 RSDB Inputs
Telecommand: ZMR19205 -IFP Power (RF) Control
Parameters: PMRG0011 -IFP Power Control, default 3, -3 dB
CMRV0006: 0, 0 1, -1 dB 2, -2 dB 3, -3 dB 4, -4 dB 5, -5 dB 6, -6 dB 7, -7 dB 8, -8 dB 9, -9 dB 10, -10 dB 11, -11 dB 12, -12 dB 13, -13 dB 14, -14 dB 15, -15 dB
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.2 Submillimeter Gunn Voltage Telecommand
6.1.5.2.1 Description
The Submillimeter Gunn Voltage Telecommand allows manual control of the submillimeter-wave Gunn oscillator voltage and hence frequency. This is desirable since the voltage that will result in the desired frequency is somewhat temperature dependent.
Note: This telecommand can be executed in the submillimeter continuum mode to control the frequency of the Gunn oscillator. However, in that case, the submillimeter Gunn oscillator is not controlled by the phase lock system.
6.1.5.2.2 Packet Definitions
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00000001 EID-A Optional, 1 = SMM Gunn Voltage
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-15 decimal, specifies the SMM Gunn Voltage
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.2.3 Parameters
The telecommand parameter is given in the packet application data. Submillimeter-wave Gunn voltage: one of sixteen values (0= 9.36V, 1= 9.29V, 2=9.23V, 3=9.16V, 4=9.09V, 5=9.02V, 6=8.95V, 7=8.88V, 8=8.81V, 9=8.74V, 10=8.67V, 11=8.60V, 12=8.53V, 13=8.46V, 14=8.39V, 15=8.32V)
6.1.5.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware.
6.1.5.2.4.1 Action Taken
Bits 0-3 of address 800 of the sensor unit control register are set to the value specified.
6.1.5.2.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. Typical values are given below.
Submillimeter Gunn Voltage Telecommand
Control Bits
SUCR, Bit 16 (NMRA0004, bit 15) Bit 0 of smm Gunn osc. voltage
SUCR, Bit 17 (NMRA0004, bit 14) Bit 1 of smm Gunn osc. voltage
SUCR, Bit 18 (NMRA0004, bit 13) Bit 2 of smm Gunn osc. voltage
SUCR, Bit 19 (NMRA0004, bit 12) Bit 3 of smm Gunn osc. voltage
Sensor Results
SMM_PLL_ERR (NMRA0055) Will become unlocked: Locked between 1.55V and 2.74V, Unlocked >2.74V or <1.55V (see typical data below)
The frequency of the Gunn oscillator changes with voltage and temperature. The variation with voltage has been measured to be +458.82 MHz/V over the range of commandable voltages. The voltage step size is 0.07V, corresponding to a change in 32.7 MHz at the Gunn oscillator frequency or 128 MHz at the sky frequency. At about room temperature telecommand of 4 = 9.09V corresponds to the required frequency of 140703.3MHz. The resultant frequency for each commandable voltage based on this slope is given below.
The frequency also varies with temperature with a slope of 0.0037 V/C at
140.7 GHz. The absolute temperature is not well calibrated. In the table below we have set the voltage at 20 C to be that corresponding to a command of 4, the value observed to be locked at room temperature. Therefore this table provides trends. Based on this the command parameter values need to stay locked over the whole operating temperature range (-20 C to 40 C) is from 6 to 3.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Command Voltage (V) Gunn Freq (GHz) LO Freq (GHz)
0 9.36 140.8271 563.309
1 9.29 140.7905 563.180
2 9.23 140.7675 563.070
3 9.16 140.7354 562.941
4 9.09 140.7033 562.813
5 9.02 140.6711 562.685
6 8.95 140.6390 562.556
7 8.88 140.6069 562.428
8 8.81 140.5748 562.299
9 8.74 140.5427 562.171
10 8.67 140.5105 562.042
11 8.6 140.4784 561.914
12 8.53 140.4463 561.785
13 8.46 140.4142 561.657
14 8.39 140.3821 561.528
15 8.32 140.3500 561.400
BaseplateTemperature( C) Gunn Bias for 140.7 GHz (V) Command
-20 8.95 6
-10 8.98
0 9.02 5
10 9.05
20 9.09 4
30 9.13
40 9.17 3
*9.09 V is the nominal voltage for a sensor baseplate temperature in vacuum of 20 C
Note: 4 is nominal for a sensor baseplate temperature of about 20 C in vacuum
Typical Phase Lock Error as a function of submillimeter-wave Gunn oscillator voltage at room temperature. The voltage for which lock is achieved is a function of temperature.
Value Submm Gunn Voltage SMM_PLL_ERR State
start 9.09 1.6311 locked
0 9.36 3.1915 unlocked
3 9.16 2.5608 locked
4 9.09 1.5818 locked
5 9.02 0.4704 unlocked
6 8.95 0.3763 unlocked
9 8.74 3.0685 unlocked
12 8.53 3.0695 unlocked
15 8.32 3.0709 unlocked
12 8.53 3.0713 unlocked
9 8.74 3.0657 unlocked
6 8.95 0.37541 unlocked
5 9.02 0.4695 unlocked
4 9.09 1.6004 locked
3 9.16 2.532 locked
0 9.36 3.1896 unlocked
4 (nominal) 9.09 1.6516 locked
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Note that the Gunn oscillator could be locked at two different voltages, though we have never seen it lock at the lower (wrong) voltage. Also there sometimes is hysteresis, though not seen here.
Impact on the science: The submillimeter-wave Gunn oscillator will become unlocked resulting in inaccurate frequency knowledge for the spectroscopic channels. The PLL alarm bits in the Spectroscopic (CTS) science data are set when the submillimeter-wave Gunn oscillator becomes unlocked. For more information see telemetry discussion in Section 7.1.3. Also the number of times that 6 PLL lock indicator bits were found to be locked and unlocked is stored in the Miscellaneous Science file under PLL lock successful counter and PLL Lock Unsuccessful counter.
6.1.5.2.4.3 Additional Information
While this command can be used to directly set the SMM Gunn Voltage there are other commands that can affect the setting of the SMM Gunn Voltage value. The "SMM Gunn Voltage Auto-control Enable/Disable" TC can enable automatic control by the software over this setting. See the description of that TC to see under what conditions the automatic control will change the setting. If the automatic control is disabled then any change made via this TC will stay in effect until a future change is made or automatic control is enabled.
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to 4.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.2.5 RSDB Entries
Telecommand: ZMR19201 - Submm Gunn Voltage
Parameters: PMRG0006 -Submm Gunn Voltage, default = 4 (9.09 V)
CMRV0003 =0-15 0, 9.36V 1, 9.29V 2, 9.23V 3, 9.16V 4, 9.09V 5, 9.02V 6, 8.95V 7, 8.88V 8, 8.81V 9, 8.74V 10, 8.67V 11, 8.60V 12, 8.53V 13, 8.46V 14, 8.39V 15, 8.32V
6.1.5.3 PLL Reset Telecommand
6.1.5.3.1 Description
The Phase Lock Loop (PLL) reset command opens (or closes) the feedback loop for the phase lock electronics.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.3.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001010 EID-A Optional, 10 = PLL Reset Control
Pad 8 00000000 EID-A Mandatory
Application Data 16 0 or 1 Setting of 0= off (loop closed) or 1=on (loop open).
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.5.3.3 Parameters The parameter is given in the packet application data. PLL Reset (PMRG0013) 0 = off (loop closed, nominal, default) 1 = on (loop open (reset))
6.1.5.3.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.3.4.1 Action Taken
Bit 12 of address 700 (SUCR) of the sensor unit control register is set to the value specified.
6.1.5.3.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. Typical values are given below.
PLL Reset Telecommand
Control Bits
SUCR, Bit 12 (NMRA0003, bit 3) Phase-lock Reset (0 locks, 1 unlocks)
Sensor Results
SMM_PLL_ERR (NMRA0055) Locked between 1.55V and 2.74V, Unlocked >2.74V or <1.55V (see typical data in previous command)
Impact on the science: The submillimeter-wave Gunn oscillator will become unlocked resulting in inaccurate frequency knowledge for the spectroscopic channels. The PLL alarm bits in the Spectroscopic (CTS) science data are set when the submillimeter-wave Gunn oscillator becomes unlocked. For more information see telemetry discussion in Section 7.1.3. Also the number of times that 6 PLL lock indicator bits were found to be locked and unlocked is stored in the Miscellaneous Science file under PLL lock successful counter and PLL Lock Unsuccessful counter.
6.1.5.3.4.3 Additional Information
This TC was originally implemented to toggle the affected bit upon receipt of the TC. It was changed to be a high or low setting.
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to 0.
6.1.5.3.5 RSDB Inputs
Telecommand: ZMR19207 -Reset PLL
Parameters: PMRG0013 -PLL Reset, default 0, Off
CMRV0005 0, off 1, on
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.4 SMM Gunn Voltage Auto-control Enable/Disable Telecommand
6.1.5.4.1 Description
MIRO is automated to adjust the submillimeter-wave Gunn oscillator voltage to stay locked over temperature. This command either enables or disables this capability.
6.1.5.4.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010101 EID-A Optional, 21 = SMM Gunn Voltage auto-control enable/disable
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 0-1: 0=auto-control disabled, 1=auto-control enabled
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.5.4.3 Parameters
The parameter is found in the packet application data. SMM Gunn Volt Enbl/Dsbl (PMRG0029): 1 = Enable (default), 0 = disable
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.4.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a global variable that controls further processing by other tasks.
6.1.5.4.4.1 Action Taken
When the auto-control capability is disabled the software control of the SMM Gunn Voltage works as follows:
1.
SMM Gunn Voltage set to 4 following every power on or software restart.
2.
Following CTS internal table initialization the SMM Gunn Voltage is set to 3.
3.
The SMM Gunn Voltage setting is increased by 1.
4.
If the last setting was 15 the SMM Gunn Voltage is set to 0.
5.
A 1-second delay occurs.
6.
The PLL Phase Error engineering measurement is sampled.
7.
If the PLL Phase Error lies between 1.55V (0x680) and 2.74V (0xb80) the SMM Gunn Voltage is left at the current value and processing continues.
8.
If the PLL Phase Error falls outside the range then go to step 3.
9.
If the desired PLL Phase Error is not achieved after 32 iterations the software exits the loop and processing continues with the SMM Gunn Voltage set to 4.
Following this the SMM Gunn Voltage remains at its last set value until it is either manually changed via TC or the instrument is repowered or the software is restarted.
When the auto-control capability is enabled the software control of the SMM Gunn Voltage works as follows:
1.
The same processing occurs as described in steps 1-9 above.
2.
Just prior to each instrument calibration if we are running in a mode where the CTS is powered on the PLL Phase Error is again checked to see if it falls within the 1.55V (0x680) to 2.74 (0xb80) range.
3.
If the value is < 1.55V (0x680) the SMM Gunn Voltage is decreased by 1.
4.
If the value is > 2.74V (0xb80) the SMM Gunn Voltage is increased by 1.
5.
Processing then continues with an instrument calibration.
6.1.5.4.4.2 Resulting Effect
When enabled, approximately every 30 minutes (instrument calibration) the SMM Gunn Voltage may be adjusted 1 count either up or down to automatically compensate for temperature-induced drift in the hardware.
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data. Typical values are given below.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Submillimeter Gunn Voltage Telecommand
Control Bits
SUCR, Bit 16 (NMRA0004, bit 15) Bit 0 of smm Gunn osc. voltage
SUCR, Bit 17 (NMRA0004, bit 14) Bit 1 of smm Gunn osc. voltage
SUCR, Bit 18 (NMRA0004, bit 13) Bit 2 of smm Gunn osc. voltage
SUCR, Bit 19 (NMRA0004, bit 12) Bit 3 of smm Gunn osc. voltage
Impact on the science: If the submillimeter-wave Gunn oscillator becomes unlocked then the frequency knowledge for the spectroscopic channels becomes inaccurate. The PLL alarm bits in the Spectroscopic (CTS) science data are set when the submillimeter-wave Gunn oscillator becomes unlocked. For more information see telemetry discussion in Section 7.1.3. Also the number of times that 6 PLL lock indicator bits were found to be locked and unlocked is stored in the Miscellaneous Science file under PLL lock successful counter and PLL Lock Unsuccessful counter.
6.1.5.4.4.3 Additional Information
As per the above pseudo-code the SMM Gunn Voltage will only be changed at most 1 setting in either direction. And the change will only occur just prior to each instrument calibration, nominally every 30 minutes.
During initial software startup following power on or during a software restart to incorporate memory patches the auto control of the SMM Gunn Voltage is enabled.
6.1.5.4.5 RSDB Inputs
Telecommand: ZMR19223 - SMM Gunn Voltage AutoCtrl Enable/Disable
Parameters: PMRG0029 - SMM Gunn Volt Enbl/Dsbl, default = 1, Enable
CMRV0021 0, Disable 1, Enable
6.1.5.5 CTS Heater Control Telecommand
6.1.5.5.1 Description
The analog part (SAW filters) of the CTS is temperature controlled. For optimum performance of the thermal feedback analog part of the CTS should be at least 20 C above ambient. This command allows you to set the temperature that the analog part of the CTS will be controlled to. In addition, the power level available for this thermal control can be specified. This latter control allows a trade between power dissipation and time to reach a certain temperature.
This command can be executed only in spectroscopic modes. In a non-spectroscopic mode the CTS warmup telecommand should be used to change the temperature for the thermal control.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.5.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 1001 EID-A Optional, Acknowledgement of Acceptance and Acknowledgement of Execution
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00000110 EID-A Optional, 6 = CTS Heater Control
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
CTS Heater Control Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
CTS Heater Power 4 0=High, 1=Off, 2=Low
CTS Heater Temperature 4 All values are degrees C; 0=0, 1=10, 2=20, 3=30, 4=40, 5=50, 6=60, 7=70
Reserved 8 Not Used
6.1.5.5.3 Parameters The parameters are contained in the application data of the packet. CTS Heater Temperature (PMRD2101): 0, 10, 20, 30, 40, 50, 60, 70 CTS Heater Power (PMRD2102): High, Off, Low
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.5.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task stores the CTS heater setting in a global variable and immediately clocks the specified setting out to the CTS.
6.1.5.5.4.1 Action Taken
A CTS command is built that contains the value specified in the application data field of the TC and sent to the CTS.
6.1.5.5.4.2 Resulting Effect
The CTS power level and temperature setting are sent to the CTS and the CTS will begin to heat up to the required temperature using the level of power specified.
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc. as measured by sensors, and
(3) impact on the science data. The direct effect of this is that the thermal control for the analog SAW filters of the CTS is turned on and set to the input temperature. The heating rate is determined by the power level. There are 6 temperature sensors in the CTS. Spect Temp 1-4 are in the analog part. Spect Temp 5-6 are in the digital part. The first four temperatures should stabilize at the commanded temperatures. The last 2 temperatures will increase by about 5-10 C. The supply voltage and current also change. The typical effect on telemetry is summarized below.
CTS Warm Up Telecommand Off On
Control Bits (already set by change mode)
Sensor Results
Spect Temp #1 (analog) (NMRA0009) ambient commanded temperature
Spect Temp #2 (analog) (NMRA0010) ambient commanded temperature
Spect Temp #3 (analog) (NMRA0011) ambient commanded temperature
Spect Temp #4 (analog) (NMRA 0012) ambient commanded temperature
Spect Temp #5 (digital) (NMRA0013) ambient ambient + 5C
Spect Temp #6 (digital) (NMRA0014) ambient ambient + 5C
+12V EU (NMRA0016) 13.20V 12.29V
+12V Curr EU (NMRA0022) 0.07A 0.31 (lo) - 0.51A (hi)
Impact on the science data: There is no easily measured impact on the science data. The CTS spectroscopic data will be more stable when the CTS SAW filters are maintained at a constant temperature.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.5.5.4.3 Additional Information
The default setting of the global variable that contains the CTS temperature and power level is 30 C and low power. The default setting of the global variable takes place when either the instrument is powered on or a software restart TC is processed. The setting of the CTS heater temperature and power level in the CTS itself does not take place until the CTS is turned on. In the case where this TC is used to set the CTS temperature and power global variable, that setting will remain in effect (in memory) even when the instrument is put into a mode where the CTS is powered off. Upon entering a mode where the CTS is again powered on the global variable will be used to set the CTS temperature and power level to the previous setting.
If the CTS is not powered on and this TC is sent to the instrument the software will not execute.
During initial software startup following power on or during a software restart to incorporate memory patches this internally stored value is set to 30 C and low power.
6.1.5.5.5 RSDB Inputs
Telecommand: ZMR19215 - CTS Heater Controls
Parameters: PMRD2101 - CTS Heater Temperature, default = 10C
CMRV0016 0, 0 deg 1, 10 deg 2, 20 deg 3, 30 deg 4, 40 deg 5, 50 deg 6, 60 deg 7, 70 deg
PMRD2102 - CTS Heater Power, default = Low Power
CMRV0017 0, High Power 1, Off 2, Low Power
PMRD2103 - Not Used
6.1.5.6 CTS Internal Calibration Telecommand
6.1.5.6.1 Description
The CTS uses four banks of analog-to-digital converters (ADCs) to generate the 4096 spectral channels. Each of the 4 banks of ADCs contains 2 high speed 8-bit ADCs. The output of the ADC banks are interspersed so that the 1st channel comes from the 1st ADC bank, the 2nd channel from the 2nd ADC bank, the 3rd
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channel from the 3 ADC bank and the 4th channel from the 4th ADC bank. The pattern of repeating, interspersed ADC banks continues through all 4096 channels. Each of the 8 individual ADCs has a different offset and gain that may drift with time and temperature. The purpose of the CTS internal calibration is to compensate for these differences.
Since the CTS internal calibration invalidates the instrument calibration, the CTS internal calibration telecommand actually does two things: (1) the actual CTS internal calibration followed by (2) a new instrument calibration.
A CTS internal calibration is performed automatically every time that the CTS is powered on. (A mode change telecommand to a spectroscopic mode will not perform a CTS internal calibration if the instrument is already in a spectroscopic mode.) This telecommand was created to allow for a re-calibration at least once a day to compensate for any temperature or power level induced changes in the CTS functioning during multi-day CTS observing periods. Once the CTS internal calibration and instrument calibrations are complete, the instrument automatically resumes in the spectroscopic mode it was in before the command was invoked.
The CTS internal calibration command should not be used unless the instrument is already operating in a spectroscopic mode. If the instrument receives a CTS internal calibration command when it is not in spectroscopic mode the command will be rejected.
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6.1.5.6.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 1001 EID-A Optional, Acknowledgement of Acceptance and Acknowledgement of Execution
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010001 EID-A Optional, 17 = CTS Internal Calibration
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Anything
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.5.6.3 Parameters
This telecommand requires no parameters.
6.1.5.6.4 Execution Description
The inbound FIFO manager task sets a variable in global memory for use by the executive task. The inbound FIFO manager task then sets the mode_change semaphore to notify the executive task that a mode change has been commanded. The executive task checks for a mode change once per second while in the nominal processing loop.
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6.1.5.6.4.1 Action Taken
Upon detection of a CTS internal calibration command the executive task begins a graceful shutdown of the software in the current mode of operation. The current CTS integration is allowed to complete. All collected science TM data is processed and flushed out to the outbound FIFO manager task as part of the graceful shutdown. Then the command causes a CTS internal calibration and an instrument calibration to be carried out. Upon completion of the command the executive task resumes the operation of the software in the same operational mode as before the command had been received.
This CTS uses as a sum of squares (SOS) look-up table as part of its processing. The SOS table is an (x,y) square 256 x 256 in size. There are four of these SOS tables, one for each ADC bank of two ADCs each. The center of the table contains 0. Proceeding outward from the center the cells are populated by the values (x2+y2) as shown in the partially filled table below.
32 16 32
18 9 18
8 5 4 5 8
5 2 1 2
16 9 4 1 0 1 4 9 16
5 2 1 2 5
8 5 4 5 8
18 9 18
32 16 32
If the ADC is perfect, with no offset, then the center of the table will be at (128, 128). The effect of an offset is to shift the table center. The CTS internal calibration procedure determines the effective center (also called midpoint) for each of the 8 ADCs. The four SOS tables are then generated with the 0 being placed in the effective center. These four SOS tables, each with their own midpoints, are then loaded into the CTS.
A two-step process is used in order to measure the effective center of a SOS table for each ADC bank. The first step determines the x center, the second the y center. To determine the x-axis center, the SOS table is loaded with a linear ramping pattern, so that each column of the table contains the same data in each row. The CTS executes 10,000 cycles and the data is read out of the CTS. A linear SOS table loaded for calculating the x-axis midpoint is shown below.
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124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
124 125 126 127 128 129 130 131 132
Again if the ADC were perfect, the average of the output of the CTS when scaled for the number of cycles would be 127.5. However, since it is not perfect the output would be different, say 126.7. This is then the computed midpoint for the x-axis ADC. Since the SOS table can only be loaded with integer values the calculated floating point table midpoint is rounded to the nearest integer value prior to subsequently computing the actual SOS table values.
A linear SOS table loaded for calculating the y-axis midpoint is shown below. A similar scheme is used, but in this case the SOS table is loaded with the linear ramping pattern in the rows not the columns.
124 124 124 124 124 124 124 124 124
125 125 125 125 125 125 125 125 125
126 126 126 126 126 126 126 126 126
127 127 127 127 127 127 127 127 127
128 128 128 128 128 128 128 128 128
129 129 129 129 129 129 129 129 129
130 130 130 130 130 130 130 130 130
131 131 131 131 131 131 131 131 131
132 132 132 132 132 132 132 132 132
Again if the ADC were perfect, the average of the output of the CTS when scaled for the number of cycles would be 127.5. However, since it is not perfect the output would be different, say 124.2. This is then the computed midpoint for the y-axis. After rounding, 124 would be used as the mid-point for computing the actual SOS table.
The two rounded midpoints for each SOS table are then used to determine the cell that contains the value 0. The entire SOS table is then generated around the zero point until the entire table is filled in as described earlier.
6.1.5.6.4.2 Resulting Effect
The x and y midpoints of the 4 sum-of-squares tables are downlinked in the miscellaneous science TM packet that gets generated immediately after the CTS internal calibration is complete. There are two midpoints for each table, one
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representing the real part of the transform, the other the imaginary part. The values of the midpoints should be about 128 if the inherent offset of the ADC banks is exactly centered with regard to a null input signal.
6.1.5.6.4.3 Additional Information
The CTS contains 4 internal sum of squares tables which are 256x256 16-bit values. These are loaded with data calculated by the flight computer and then transferred to the CTS. The CTS uses them to process the CTS spectrum. The process of determining what values to load into the sum-of-squares tables prior to nominal data collection is the CTS internal calibration process.
The CTS does not turn on correctly if its operating temperature is below about -5 C. When this occurs the one or more of CTS internal calibration midpoints are orders of magnitude larger than the expected value of around 127. When temperatures are this low the CTS warm up command should be used prior to entering any spectroscopic mode.
6.1.5.6.5 RSDB Inputs
Telecommand: ZMR19216 - CTS Internal Calibration
Parameters: PMRG0022 - CTS Internal Calibration
6.1.5.7 CTS Data Masks Telecommand
6.1.5.7.1 Description
The CTS generates spectra that consist of 4096 channels of 32-bit data. The flight software compresses the 32-bits to 12-bits. The default compression algorithm looks for the channel with the largest value within each of 7 spectral bands (defined in Section 9.3.4). It identifies the high bit associated with this value and then makes that the most significant bit for all the channels of that band by stripping off the higher bits with zero value. Then it goes down 12 bits below this high bit and strips off the lower bits. (Note that this algorithm was changed by a software patch-and patches must be re-loaded each time the instrument is turned on-starting in September 2009. Prior to that date, the location of the high bit to be returned was the same for all bands. If one band had a much higher signal than another, that had the potential of reducing to an unacceptable value the dynamic range of the band with the weak signal. The CTS Data Mask telecommand was designed to avoid this by allowing manual selection of the 12 bits within each spectral band. The revised software reduces the need for this telecommand, though there are situations where it still might be useful.)
This telecommand manually sets the high bit above which bits are stripped. The CTS spectra are a composite of 7 bands (Section 9.3.4). Each band may have significantly different gains. In addition, calibration data and regular differenced data have very different values. Therefore a total of 14 most significant bits can be set, seven associated with the calibration data in each band and seven for regular differenced data in each band.
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6.1.5.7.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000010011 This gets set to the size of the application data field (in bytes) + 5. In this case, 19.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010010 EID-A Optional, 18 = CTS Data Masks
Pad 8 00000000 EID-A Mandatory
Application Data 112 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
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CTS Data Masks Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Calibration band #1 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #2 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #3 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #4 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #5 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #6 MSB 8 Varies Valid setting is in the range of 11-31
Calibration band #7 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #1 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #2 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #3 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #4 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #5 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #6 MSB 8 Varies Valid setting is in the range of 11-31
Nominal band #7 MSB 8 Varies Valid setting is in the range of 11-31
6.1.5.7.3 Parameters
The parameters are given in the packet application data definition.
The value assigned to the parameters is an integer in the range from 11 to 31.
(PMRD2301) Calibration Band#1 MSB (PMRD2302) Calibration Band#2 MSB (PMRD2303) Calibration Band#3 MSB (PMRD2304) Calibration Band#4 MSB (PMRD2305) Calibration Band#5 MSB (PMRD2306) Calibration Band#6 MSB (PMRD2307) Calibration Band#7 MSB (PMRD2308) Nominal Band#1 MSB (PMRD2309) Nominal Band#2 MSB (PMRD2310) Nominal Band#3 MSB (PMRD2311) Nominal Band#4 MSB (PMRD2312) Nominal Band#5 MSB (PMRD2313) Nominal Band#6 MSB (PMRD2314) Nominal Band#7 MSB
6.1.5.7.4 Execution Description
The inbound FIFO manager task parses the 14 mask values out of the TC and populates a global array that will be used by the CTS final processing task.
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6.1.5.7.4.1 Action Taken
Following the population of the global mask array the inbound FIFO manager task generates a miscellaneous science TM packet containing, among other things, the current set of mask values.
6.1.5.7.4.2 Resulting Effect
Immediately following the processing of the TC and the setting of the global mask variables all CTS data sets that are generated will reflect the use of the masks.
Typical values for the most significant bit by the autonomous compression routine are MSB=25 for calibration data and MSB=17 for regular differenced data. The value of the MSB for the calibration data depends on the IFP power setting. The value for the MSB for the regular differenced data depends on the noise in the spectrum (integration time, receiver temperature). The autonomous value is stored in the spectroscopic (CTS) science source data packet and named CTS multiplier value. Note that the 11 must be added to this value to get the number to input into this command. Therefore if the multiplier value is 12, then to get the same effect the input to this command is 23. When this command is executed the multiplier value is set to 0 and the user-defined values are placed in the miscellaneous science file.
If the most significant bit of one band is increased by one bit, then it will appear a factor of two smaller when compared to the other bands.
6.1.5.7.4.3 Additional Information
CTS data sets generated as a result of an uplinked mask are identified by having the "CTS Multiplier Value" data element set to zero. In this case the masks sent out in the most recent miscellaneous science TM packet must be used to expand the raw 12-bit CTS values out to their actual size.
Once a CTS data mask has been uplinked there is no way to "drop back" to using the auto calculated value for CTS data set MSB determination. The only way to get back to that mode of operation is to issue a software restart command or repower the instrument.
During initial software startup following power on or during a software restart to incorporate memory patches the mask values for the 7 calibration bands are set to 0, and the 7 nominal bands are set to 11. Also, auto calculation of the MSB of each data set is re-enabled.
6.1.5.7.5 RSDB Inputs
Telecommand: ZMR19217 - CTS Data Masks
Parameters: PMRD2301 Calibration Band#1 MSB
CMRV0018 11, MSB=11 12, MSB=12
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13, MSB=13 14, MSB=14 15, MSB=15 16, MSB=16 17, MSB=17 18, MSB=18 19, MSB=19 20, MSB=20 21, MSB=21 22, MSB=22 23, MSB=23 24, MSB=24 25, MSB=25 26, MSB=26 27, MSB=27 28, MSB=28 29, MSB=29 30, MSB=30 31, MSB=31
PMRD2302 Calibration Band#2 MSB
CMRV0018
PMRD2303 Calibration Band#3 MSB
CMRV0018
PMRD2304 Calibration Band#4 MSB
CMRV0018
PMRD2305 Calibration Band#5 MSB
CMRV0018
PMRD2306 Calibration Band#6 MSB
CMRV0018
PMRD2307 Calibration Band#7 MSB
CMRV0018
PMRD2308 Nominal Band#1 MSB
CMRV0018
PMRD2309 Nominal Band#2 MSB
CMRV0018
PMRD2310 Nominal Band#3 MSB
CMRV0018
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PMRD2311 Nominal Band#4 MSB CMRV0018
PMRD2312 Nominal Band#5 MSB CMRV0018
PMRD2313 Nominal Band#6 MSB CMRV0018
PMRD2314 Nominal Band#7 MSB CMRV0018
6.1.5.8 CTS Run Time Telecommand
6.1.5.8.1 Description
This telecommand is used to minimize overhead in the timing when both the spectroscopic and continuum data are being collection (i.e., during spectroscopic modes-CTS/SMMContinuum and CTS/Dual Continuum modes). The objective is to reduce that gap from its worse case of 500 milliseconds to about 20 milliseconds, by increasing the CTS run time.
The continuum and spectrometer detailed timeline is given below. The figure shows the detail at the end of a 5 sec LO frequency switch. During each
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~5 seconds CTS scan, 100 continuum samples are read out. A time gap is introduced between the time when the 100th continuum sample is read out and the next 5 second CTS scan is started. The reason for introducing this gap is that there is an uncertainty in the continuum sample readout of +/-1%, which means that the 100th sample could be readout anywhere between 4.95 and 5.05 seconds. The CTS run time is programmable by this telecommand. Its default setting is 4.95 seconds, the minimum time for the 100th continuum sample to be read out. This is returned in the Miscellaneous Science data. Also the time to readout the CTS data is uncertain, between 230 and 500 milliseconds. When the program starts up the worse case is assumed, that both the 100th sample is read out at 4.95 seconds and the CTS readout takes 500 milliseconds. The next CTS scan and continuum readout then start at 5.225 sec. The gap, called the continuum/CTS unloading gap, from the actual 100th continuum interrupt until the actual CTS readout is complete is returned in the Miscellaneous science file.
6.1.5.8.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001100 EID-A Optional, 12 = CTS run time setting
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
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CTS Run Time Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Large Multiplier 1 When set to 1, multiply the results obtained from the small multiplier by an additional 256.
Small Multiplier 1 When set to 1, multiply the integration counts field by 16.
Integration Counts 14 Varies Integration counts. Each count equals ~22.35 microseconds.
6.1.5.8.3 Parameters
The telecommand parameters are identified in the packet application data definition.
Large multiplier (PMRD1601): 0, 1 - multiply small multiplier by
256largemultiplier, default = 0.
Small multiplier (PMRD1602): 0, 1 - multiply integration counts by
16smallmultiplier, default = 1.
Integration counts (PMRD1603): default = 13858
(each count = ~22.35 microseconds).
6.1.5.8.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the hardware. The internal variable that is used to keep track of the average CTS scan times is zeroed as this command directly affects the CTS scan duration. The internal variable that is used to track the minimum duration from the 100th continuum interrupt being received until the CTS readout complete is also initialized to 10.0 as increasing or decreasing the CTS run time will directly affect this value. Both of these values appear as TM in the miscellaneous science packet.
6.1.5.8.4.1 Action Taken
The global variable that is used to control the CTS integration cycle count is set to the specified value.
The CTS scan duration, beginning with the next CTS integration, will be set to the number of cycles specified in the global variable. The global variable will remain set to the specified value until either (1) power down/up (2) software restart
(3) receipt of new CTS Run Time command.
6.1.5.8.4.2 Resulting Effect
The CTS scan duration will be set to the number of cycles specified. The 100th continuum cycle is read out in a range from 4.95 seconds to 5.05 seconds. The time for the CTS data to unload is from 0.19 to 0.50 seconds. Then the range for
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the gap as a function of CTS run time is given in the Table below. The gap should not be less than 0.02 seconds. As you can see from the table below the range for the CTS run time is between 4.956 (default from large multiplier =0, small multiplier = 1, integration counts = 13858) and 4.47 seconds (large multiplier = 0, small multiplier =1, integration counts =12499).
Large Multiplier 0 0 0 0 0 0 0
Small Multiplier 1 1 1 1 1 1 1
Integration Counts 13858 13701 13422 13142 12863 12583 12499
CTS Run Time (sec) 4.956 4.9 4.8 4.7 4.6 4.5 4.47
Max Gap (sec) 0.506 0.45 0.35 0.25 0.15 0.05 0.02
Min Gap (sec) 0.096 0.04 -0.06 -0.16 -0.26 -0.36 -0.39
The CTS Run time and continuum/CTS unloading gap in seconds are read out in the Miscellaneous Science file. The Gap is initially set to 10.0 to indicate when it hasn't been updated.
The CTS is considered to have failed if the busy line of the CTS is still high during the 100th continuum interrupt processing. The busy line normally goes low at the completion of the CTS scan. If the busy line stays high, a graceful software shutdown will occur returning the instrument to the engineering mode. A CTS Error Event Report (YMR00015) will be generated.
6.1.5.8.4.3 Additional Information
Operationally this TC should be used to decrease the "continuum/CTS unloading gap" value in the miscellaneous science packet down to a value of about
0.020 seconds.
A short experiment indicates that for the case where
Large multiplier = 0,
Small multiplier = 1, and
Integration Counts = 13620
results in a gap of .02 seconds. This implies that the CTS unloading time is just under 0.2 seconds. This however should be verified in flight.
The methodology for doing this should be as follows. A miscellaneous science packet is generated every 30 minutes of nominal operation as part of the instrument calibration. The "continuum/CTS unloading gap" should be monitored in each of the miscellaneous science packets that get generated at 30 minute intervals due to instrument calibration. Miscellaneous science packets also get generated for a variety of other reasons, and the "continuum/CTS unloading gap" values in those TM packets should not be used. When the "continuum/CTS unloading gap" as reported in the miscellaneous science packet stops decreasing over time the value should be noted. Assume that the value has stabilized at
0.100 seconds. The CTS run time will now need to be adjusted to a lower value in order to decrease the "continuum/CTS unloading gap". It CTS run time should
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not be lowered to a value to immediately reduce the gap from 0.100 to the desired
0.020 value, but gradually decreased over perhaps 3 or 4 iterations. If we wanted to lower it from 0.100 to 0.050 we would need to decrease the CTS run time by about 2272 cycles (0.050/0.000022). The CTS run time would then be changed from the nominal value of 30242 (221728 cycles) to 30100 (219456 cycles). The "continuum/CTS unloading gap" should then be monitored until it stops decreasing again, and the process repeated to lower the gap closer to the desired value of 0.020. Once the process has been repeated several times and the gap has been reduced to the 0.020 level the CTS run time being used should be noted. This CTS run time should then be uplinked via TC every time the instrument is repowered or restarted to implement a memory patch. This is the CTS run time that should be used for long-term operation. Once this process has been completed the "continuum/CTS unloading gap" should still be monitored over time to insure that it maintains the 0.020 nominal level. Further small adjustments may be required over time due to temperature, power or other variables.
During initial software startup following power on or during a software restart to incorporate memory patches this value is set to 30242. The 30242 corresponds to 0x7622. Bit 14 serves as an indicator to multiply the value specified in bits 0-13 by 16. Bit 15 serves as an indicator to further multiple the resulting value by an additional 256. The initial setting of 0x7622 represents 0x3622 * 0x10 which totals 221728. This number is the number of cycles that the CTS is set to run for, where each cycle is approximately 22.35 microseconds duration.
6.1.5.8.5 RSDB Inputs
Telecommand: ZMR19210 - CTS Run Time
Parameters: PMRD1601 - Large Multiplier
CMRV0008 0, 0 1, SmlMultx256
PMRD1602 - Small Multiplier
CMRV0009 0, 0 1, IntCntsx16
PMRD1603 - Integration Counts
6.1.5.9 CTS Pulse Position Telecommand
6.1.5.9.1 Description
This telecommand translates the CTS spectrum with respect to channel number, by approximately 4 spectral channels per unit change in the pulse position number. The default position is 410. This telecommand would allow adjustment of the frequency offset that might result from a change in the CTS function. This is not anticipated.
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6.1.5.9.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 1001 EID-A Optional, Acknowledgement of Acceptance and Acknowledgement of Execution
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00001101 EID-A Optional, 13 = CTS pulse position setting
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable See CTS ICD for additional information
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.5.9.3 Parameters
CTS pulse position (PMRG0017) = 410 (default)
6.1.5.9.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task immediately clocks the specified setting out to the CTS.
6.1.5.9.4.1 Action Taken
A CTS command is built that contains the value specified in the application data field of the TC and sent to the CTS.
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6.1.5.9.4.2 Resulting Effect
There is no telemetry that indicates the value of the pulse position. However, it turns out that there is an internal "birdie" in the instrument that results in a signal at 1364.7 MHz when the CTS pulse position is set to 410 (default). The effect of this telecommand is to translate the spectrum with respect to channel number by approximately 4 channels/unit change. So, for instance when the CTS pulse position is set to 510, the birdie will move 400 channels (each channel is about 44 kHz wide, see Section 9.4) to ~1347.1 MHz.
6.1.5.9.4.3 Additional Information
The CTS pulse position is only sent out to the CTS at two times. When the CTS internal tables are calibrated this is sent out just prior to the start of that processing. When the TC itself is received the value is also clocked out to the CTS. The value received in the TC is stored internally and used during subsequent internal CTS calibrations.
During initial software startup following power on or during a software restart to incorporate memory patches this internally stored value is set to 410 and used when a CTS internal calibration takes place.
If the CTS is not powered on and this TC is sent to the instrument the software will fail in a manner that is TBD. If the CTS pulse position telecommand is sent during the integration of a CTS scan, the signal at each channel may be altered, resulting in changes to the outputted differenced spectrum.
6.1.5.9.5 RSDB Inputs
Telecommand: ZMR19211 - CTS Pulse Position
Parameters: PMRG0017 - CTS Pulse Position, default = 410
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.6 CALIBRATION MIRROR CONTROL TELECOMMANDS
6.1.6.1 Move Mirror Telecommand
6.1.6.1.1 Description This telecommand will move the calibration mirror to any of its preset positions- space, hot load, and cold load.
6.1.6.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 01100110 EID-A Optional, 102 = Move Mirror
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable 1-3 decimal: 1=Space, 2=Hot Target, 3=Cold Target
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.6.1.3 Parameters
The parameter is given in the packet application data. Move Mirror (PMRG0018): 1 = space (default), 2= hot load, 3= cold load
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.6.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore that activates the memory check task. The memory check task performs the actual moving of the mirror as required by the command.
6.1.6.1.4.1 Action Taken
The mirror is moved from its current location to the specified location.
6.1.6.1.4.2 Resulting Effect
The resulting effect has three parts-(1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc., as measured by sensors, and
(3) impact on the science data.
Calibration Heater Telecommand Off On
Control Bits
SUCR, Bit 28 (NMRA0004, bit 3)* 1 0
SUCR, Bit 29 (NMRA0004, bit 2)* 0=forward, 1=backward
SUCR, Bit 31 (NMRA0004, bit 0)* Set and clear to activate pin puller
Sensor Results
Mirror Location (NMRA00006) 1=sky, 2=hot, 3=cold
+24 V EU (NMRA0020)* See spike
+24 V Current (NMRA0026)* See spike
*May be ob for less than 11 sec, so engineering data may miss it
The impact on the science data:
The mirror location is returned with the CTS Science source data, the Submillimeter Continuum Source Data, and the Millimeter Continuum Source Data.
Event Reports:
Failure of the mirror returns event reports
*
Mirror Error Type 1 (YMR00002) is generated when the mirror fails to achieve the desired position, but is then successfully driven back to its mechanical stop and then positioned at space.
*
Mirror Error Type 2 (YMR00003) is generated when the mirror fails to achieve the desired position, is then driven back to its mechanical stop and then fails to find space position.
*
Mirror Error Type 3 (YMR00004) is generated when the mirror fails to achieve the desired position, is then driven back to its mechanical stop and then fails to find the space position, the pin puller is activated and the space position located successfully.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
*
Mirror Error Type 4 (YMR00005) is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position, the pin puller is activated and the space position is not located.
*
Mirror Error Type 5 (YMR00006) is generated when the previous mirror failure was recovered from and was followed by a subsequent failure.
6.1.6.1.4.3 Additional Information
The memory check task is used to perform the mirror movement because the movement requires several seconds of time to execute, and we do not want to delay the processing of the inbound FIFO manager task while that is taking place.
Mirror movement fault protection is in place during the mirror movement; i.e., any failure to reach the desired location will result in recovery actions taking place. A pin puller releases the mirror and it is returned to the mechanical stop position by a spring. The pin puller is then re-engaged.
Once manually moved via this command the mirror will remain in the location specified, unless manually moved again, until the next instrument calibration occurs. At that time the mirror will be automatically moved by the software to support instrument calibration. At the end of the instrument calibration the mirror will be pointing to the space location.
During initial software startup following power on or during a software restart to incorporate memory patches the mirror is driven back to the mechanical stop and moved forward until it reaches the space position.
6.1.6.1.5 RSDB Inputs
Telecommand: ZMR19212 - Move Mirror
Parameters: PMRG0018 - Move Mirror, default = space
CMRV0011 1, space 2, hot 3, cold
6.1.6.2 Step Mirror Telecommand
6.1.6.2.1 Description
The Step mirror command moves the mirror the commanded number of steps in either the forward (from mechanical stop) or backward (toward mechanical stop) direction.
The calibration mirror is driven by a stepping motor with 0.27-degree step size. The space position is near the mechanical stop. The hot load is 41 (152 Figure 6.1-1: Anglessteps) degrees from the space position, while the associated with cold load is 23 (85 steps) degrees from the hot load. Calibration mirror
positions
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
The calibration loads are 5 cm in diameter. The hot load is located approximately 8 cm from the calibration mirror while the cold load is located about 28 cm from the calibration mirror. Therefore the hot load half angle at the calibration mirror is roughly 17 (63 steps) degrees, while the cold load half angle at the mirror is about 5 degrees (18 steps). These angles are shown in Figure 6.1-1.
6.1.6.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 00010100 EID-A Optional, 20 = Step Mirror
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Step Mirror Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Movement Direction 8 0=forward, 1=backward
Number of steps 8 0-255
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.6.2.3 Parameters
Mirror movement direction (PMRD2801): 0 = forward (from space to hot to cold), 1 = backwards (from cold to hot to space)
Number of steps (PMRD2802): 0 - 255 (note 237 steps will go from space to cold)
6.1.6.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore that activates the memory check task. The memory check task performs the actual stepping of the mirror as required by the command.
6.1.6.2.4.1 Action Taken
The mirror is moved a series of single steps from its current location in the specified direction.
6.1.6.2.4.2 Resulting Effect
The resulting effect has three parts: (1) the software command is reflected in either Address Register 100 or the Sensor Unit Control Register (SUCR) control bits, (2) the change in temperature, voltage, etc. as measured by sensors, and
(3) impact on the science data.
Calibration Heater Telecommand Off On
Control Bits
SUCR, Bit 28 (NMRA0004, bit 3)* 1 0
SUCR, Bit 29 (NMRA0004, bit 2)* 0=forward, 1=backward
SUCR, Bit 31 (NMRA0004, bit 0)* Set and clear to activate pin puller
Sensor Results
+24 V EU (NMRA0020)* See spike
+24 V Current (NMRA0026)* See spike
*May be for less than 11 sec, so engineering data may miss it
6.1.6.2.4.3 Additional Information
The memory check task is used to perform the mirror movement because the movement could require several seconds of time to execute, and we do not want to delay the processing of the inbound FIFO manager task while that is taking place.
Mirror movement fault protection is not in place during the mirror movement because the mirror is not being move to a desired location, only some number of steps that will likely not place it on one of the position sensors.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
This step movement of the mirror does not alter the internal variable used to track where the mirror is pointing. If the mirror had been pointing to space prior to receiving and executing this command, upon movement completion the internal variable will indicate that the mirror is still pointing at space. This could result in problems during the next instrument calibration if the mirror were stepped too far and mirror fault protection executes because the desired position is not achieved as expected. The reason the software does not attempt to more accurately "keep track" of the actual location of the mirror during stepping is because this capability was added late in the software development effort for the sole purpose of determining if the mirror position sensors were positioned to accurately reflect the optimum optical path. If this command is used in flight, it should be done so carefully, keeping track of the steps so that it can be returned to a nominal position.
Due to the above, the mirror location returned in NMRA0006 and the science data is not changed by this command. If no command has been issued to return to a preset mirror location, these values will be incorrect.
6.1.6.2.5 RSDB Inputs
Telecommand: ZMR19222 - Step Mirror
Parameters: PMRD2801 - Movement Direction, default = 0, forward
CMRV0020 0, forward 1, backward
PMRD2802 - Number of Steps, default = 0
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.7 SOFTWARE TELECOMMANDS
6.1.7.1 Software Restart Telecommand
6.1.7.1.1 Description
The software restart telecommand is used for several purposes: (1) to implement a patch that has been loaded by the load memory telecommand, (2) to reset parameters, such as the CTS mask parameters to default, without turning off the whole instrument, and (3) to restart the system if for some reason it is not responding.
This command should be implemented while in engineering mode.
6.1.7.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Private Telecommand = 192
Packet Subtype 8 01100111 EID-A Optional, 103 = Software Restart
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Anything
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.7.1.3 Parameters
S/W Pwr Down (PMRG0019 ): value isn't used for anything
6.1.7.1.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore that is acted upon by the executive assembly. The executive assembly checks the setting of the restart semaphore once per second when running in the nominal processing loop. When the executive sees that the restart semaphore has been set it begins the processing required to restart the software.
6.1.7.1.4.1 Action Taken
The executive assembly deletes all created tasks, message queues and semaphores prior to exiting. The patch executive task detects that the executive task has terminated and processes the entire set of memory patches that exist. The software is then restarted with all memory patches in effect.
6.1.7.1.4.2 Resulting Effect
All memory patches uplinked since the last power on will be in effect once the software restarts.
6.1.7.1.4.3 Additional Information
The executive assembly does not check the software restart semaphore during instrument calibration processing. Because of this the restart command should only be sent while the instrument is in engineering mode.
From the time that the inbound FIFO task manager receives the software restart command until the restart processing is complete and the software is back up and running is approximately 10 seconds. During this time no TCs should be sent to the instrument, as there is no software running to process them.
All internally buffered data within the instrument awaiting collection by the spacecraft will be lost during the software restart.
A software restart results in the same initial state as when the instrument is first powered on. No uplinked settings for any commandable items are retained through the software restart.
6.1.7.1.5 RSDB Inputs
Telecommand: ZMR19213 - Software Restart
Parameters: PMRG0019 - S/W Pwr Down (Grnd Test)
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
6.1.7.2 Memory Checksum Telecommand
6.1.7.2.1 Description
This telecommand will carry out a checksum of the memory specified in the parameters. It does a complete checksum of memory, but only a partial checksum (every other word) of the eepprom.
6.1.7.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000001101 This gets set to the size of the application data field (in bytes) + 5. In this case, 13.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 00000110 EID-A Specified, Memory Management = 6
Packet Subtype 8 00001001 EID-A Specified, 9 = Check Memory
Pad 8 00000000 EID-A Mandatory
Application Data 64 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Memory Checksum Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Memory ID 8 01100100 100 = MIRO's assigned ID
Number of blocks 8 00000001 Must be 1.
Start address 32 Variable Must be quadword aligned. RAM range is 0x00000000 through 0x01FFFFFF. ROM range is 0xFF800000 through 0xFF8FFFFF.
Block Length 16 Variable Number of quadwords (32 bit words) to check. 64k-1 maximum quadwords.
6.1.7.2.3 Parameters
The parameters are given in the telecommand application data.
The two that can be set are:
Start address (PMRG0002): for patch uploads a candidate is 0x300000, the RAM range is 0x0000000 through 0x1FFFFFF, for EEPROM the range is 0xFF800000 through 0xFF8FFFFF and in 0x8000 long sections this is 0xFF800000, 0xFF820000, 0xFF840000, 0xF860000, 0xF880000, 0xFF8A0000, 0xFF8C0000, 0xFF8E0000.
Block length (PMRG0003): the number of quadwords (32 bit words) to check.
6.1.7.2.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore to tell the memory check task to perform the memory checksum processing.
6.1.7.2.4.1 Action Taken
The memory check task performs the checksum over the specified address range of ROM or RAM memory. For the ROM the checksum is incomplete, checking only every other quadword.
6.1.7.2.4.2 Resulting Effect
A TM packet (YMR00008) is generated in response to this TC that contains the final memory checksum calculated.
Start Address NMRAST51 copied from TC
Block Length NMRAST52 copied from TC
Checksum NMRAST54
Note: The checksums for the EEPROM start addresses above are in table below.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Start Address Checksum
0xFF800000 0xDE39
0xFF820000 0xA511
0xFF840000 0x74DB
0xFF860000 0xCC56
0xFF880000 0x0A8B
0xFF8A0000 0xBEFC
0xFF8C0000 0x3743
0xFF8E0000 0x84C0
6.1.7.2.4.3 Additional Information
The checksum algorithm used is the ESA standard as defined in the EID-A document.
6.1.7.2.5 RSDB Inputs
Telecommand: ZMR00603 - Check MIRO Memory Parameters: PMRG0001 -Memory Block PMRD0101 - Memory ID, default = 100
PMRD0102 - Blocks, default = 1 PMRG0002 - Memory Start PMRG0003 - Memory Length
6.1.7.3 Memory Dump Telecommand
6.1.7.3.1 Description
This telecomm and will dump out either RAM or EEPROM memory of a commandable length starting at a commandable location.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.7.3.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000001101 This gets set to the size of the application data field (in bytes) + 5. In this case, 13.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 00000110 EID-A Specified, Memory Management = 6
Packet Subtype 8 00000101 EID-A Specified, 5 = Dump Memory
Pad 8 00000000 EID-A Mandatory
Application Data 64 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Memory Dump Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Memory ID 8 01100100 100 = MIRO's assigned ID
Number of blocks 8 00000001 Must be 1.
Start address 32 Variable Must be quadword aligned. RAM range is 0x00000000 through 0x01FFFFFF. ROM range is 0xFF800000 through 0xFF8FFFFF.
Block Length 16 Variable Number of quadwords (32 bit words) to check. 64k-1 maximum quadwords.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.7.3.3 Parameters The parameters are given in the telecommand application data. The two that can be set are
*
Start address (PMRG0002): the RAM range is 0x0000000 through 0x1FFFFFF, for EEPROM the range is 0xFF800000 through 0xFF8FFFFF.
*
Block length (PMRG0003): the number of quadwords (32 bit words) to dump.
6.1.7.3.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task sets a semaphore to tell the memory check task to perform the memory dump processing.
6.1.7.3.4.1 Action Taken
The memory check task performs the dump of the specified address range of ROM or RAM memory.
6.1.7.3.4.2 Resulting Effect
One or more memory dump TM packets (YMR00007) are generated in response to this TC that contains the memory contents of the requested area.
Start Address NMRAST51 copied from TC
Block Length NMRAST52 copied from TC
Memory Data NMRAST53 Contents of dump
6.1.7.3.4.3 Additional Information
The memory dump request can specify as many as 256k bytes of data, 64k quadwords. Memory dump TM packets are created with the largest size allowed by the EID-A specification.
Memory dump TM packets are trickled out at a rate of one per collection cycle of the DMS. If the DMS collection cycle is every 8 seconds then a 256k byte dump contained in 65 TM packets will be output in 520 seconds.
Only the first memory dump telemetry packet contains all the header information-this therefore requires separate handling by ESOC. Specifically the Memory ID field type should contain "sub-type 6" which defines the format of the memory dump telemetry packets. The second and subsequent packets of each memory dump do not have this information.
The message queue data structure in the outbound FIFO manager task that is used to hold the memory dump TM packets is sized to hold no more than 65 packets. A memory dump of the maximum allowable 256k bytes of memory should not be performed until it is known that the data structure is empty. The message queue associated with the dump TM packets needs to be managed as a consumable resource, in that memory dumps should not be requested that would generate more TM packets than are available in the queue at that time. Since it is not
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
anticipated that the memory dump TC will be used very frequently this should not be difficult to do.
Since the dump parameters (start address, end address, etc.) are stored in global memory by the inbound FIFO manager task for use by the memory check task another precaution must be taken. Processing of the memory dump request and generation of the TM packets requires 20 or 30 seconds of clock time by the memory check task. During this time it is important that another memory dump, memory checksum or memory load command not be sent as the memory dump that is in progress will be corrupted.
The simplest way to avoid any problems with memory checksum and memory dump processing is to wait for the associated TM data to be sent out of the instrument. At that point it is safe to send the next such request.
6.1.7.3.5 RSDB Inputs
Telecommand: ZMR00602 - Dump MIRO Memory
Parameters: PMRG0001 -Memory Block
PMRD0101 - Memory ID, default = 100 PMRD0102 - Blocks, default = 1
PMRG0002 - Memory Start
PMRG0003 - Memory Length
6.1.7.4 Memory Load Telecommand
6.1.7.4.1 Description
The memory load telecommand loads a patch into an intermediate storage location. Note that the load command does not actually patch memory.
The procedure for patching requires the following sequence.
1.
Execute the load memory telecommand-this places the patch in a temporary location
2.
Execute the stop the time update telecommand
3.
Execute the software restart telecommand-the patch is loaded into its proper location
4.
Execute the start time update telecommand
5.
Execute the check memory telecommand on the proper location-this determines if the patch is successfully loaded.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.7.4.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 Variable This gets set to the size of the application data field (in bytes) + 5.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 00000110 EID-A Specified, Memory Management = 6
Packet Subtype 8 00000010 EID-A Specified, 2 = Load Memory
Pad 8 00000000 EID-A Mandatory
Application Data 64 Variable Detailed definition on following page
Packet Error Control 16 Variable Telecommand Packet Checksum
Memory Load Telecommand Application Data Definition
Data Element Size (bits) Value (binary) Comment
Memory ID 8 01100100 100 = MIRO's assigned ID
Number of blocks 8 00000001 Must be 1.
Start address 32 0 Not used by software as part of memory loading but must pass address validation check. Hence the forced zero.
Block Length 16 Variable Number of quadwords (32 bit words) that follow in the data block field. If the data block exceeds the maximum TC packet size it must be split up into more than 1 TC.
Data Block Varies Variable Contains memory load information.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.7.4.3 Parameters
The parameters are given in the telecommand application data.
The three that can be set are
*
Start address (PMRG0002): not used, however needs to have value to pass formatting check
*
Block length (PMRG0003): the number of quadwords (32 bit words) to load,
*
Data block (PMRG0004): the 1st quadword contains the memory address where the patch is to be loaded following a software restart (0x00300000 was used during SVT), the second quadword is the number of quadwords of data that follow, and the subsequent quadwords the data to be loaded into memory.
6.1.7.4.4 Execution Description
Upon receipt of this TC the inbound FIFO manager task populates the main patch area of memory with the contents of the data block field.
6.1.7.4.4.1 Action Taken
The data from the "Data Block" area of the TC is appended to the current contents of the patch array in global memory. The amount of data to be appended is solely based on the "Block Length" field. The "Start Address" field of the TC is not applicable as the patch data is loaded sequentially into this pre-defined area of memory.
6.1.7.4.4.2 Resulting Effect
The contents of the current TC are appended to all accumulated memory patches.
6.1.7.4.4.3 Additional Information
All uplinked patches will be incorporated into the instrument upon receipt of a software restart command.
6.1.7.4.5 RSDB Inputs
Telecommand: ZMR00601 - Load MIRO Memory
Parameters: PMRG0001 - Memory Block
PMRD0101 - Memory ID, default = 100 CMRV0002
100,100
PMRD0102 - Blocks, default = 1
PMRG0002 - Memory Start
PMRG0003 - Memory Length
PMRG0004 - MemData
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8 S/C INTERFACE TELECOMMANDS
6.1.8.1 Enable MIRO HK Generation Telecommand
6.1.8.1.1 Description
This telecommand starts MIRO engineering housekeeping data transfer to the "outbound fifo management task" for transmission to the SC.
6.1.8.1.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Housekeeping Reporting=3
Packet Subtype 8 00000100 EID-A Optional, 5=Enable HK Report Generation
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable PAD=1, Structure ID=1
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.8.1.3 Parameters
PAD (PMRDSID1) = 1 (default)
Structure ID (PMRDSID2): identifier of which HK report to be acted on = 1 (MIRO has only one HK report)
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.1.4 Execution Description
6.1.8.1.4.1 Action Taken
On receipt MIRO starts generation of the HK report. The engineering housekeeping collection task is running and collecting engineering data whenever MIRO is on. It packetizes the data too. This occurs every 11.3 seconds unless the engineering housekeeping cycle skip telecommand has been executed. The only effect that turning the HK generation on is that the housekeeping data is transferred to the "outbound fifo management task" for transmission to the SC.
6.1.8.1.4.2 Resulting Effect
Generation of MIRO Housekeeping Data packets (YMR00001) is enabled (see Section 7.1.2 for description).
6.1.8.1.5 RSDB Inputs
Telecommand: ZMR00301 - Enable MIRO HK Generation
Parameters: PMRDSID1 -Pad
CMRV0001 1, default
PMRDSID2 - SID
CMRV001 1, default
6.1.8.2 Disable MIRO HK Generation Telecommand
6.1.8.2.1 Description
This telecommand stops the MIRO housekeeping packet transfer to the "outbound fifo management task" for transmission to the SC.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.2.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Housekeeping Reporting=3
Packet Subtype 8 00000100 EID-A Optional, 6=Disable HK Report Generation
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable PAD=1, Structure ID=1
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.8.2.3 Parameters
PAD (PMRDSID1): default = 1
Structure ID (PMRDSID2): identifier of which HK report to be acted on =1 (MIRO has only one HK report)
6.1.8.2.4 Execution Description
6.1.8.2.4.1 Action Taken
On receipt MIRO stops generation of the HK report. When HK telemetry generation is off the engineering collection task is still running and collecting engineering data. It packetizes the data too. The only effect that turning the HK generation off has is that the completed telemetry packets are dropped on the floor instead of being transferred to the "outbound fifo management task" for
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
transmission to the SC. If engineering housekeeping data collection is interfering with the quality of science data, then disabling HK telemetry generation will not fix that problem. They will need to use the "engineering HK cycle skip" command.
6.1.8.2.4.2 Resulting Effect
Generation of MIRO Housekeeping Data packets (YMR00001) is disabled.
6.1.8.2.5 RSDB Inputs
Telecommand: ZMR00302 - Disable MIRO HK Generation
Parameters: PMRG0SID -Pad/SID
PMRDSID1 -Pad CMRV0001 1, default
PMRDSID2 - SID CMRV001 1, default
6.1.8.3 Time Update Telecommand
6.1.8.3.1 Description
This telecommand sends the spacecraft time to MIRO.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.3.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Time Synchronization=9
Packet Subtype 8 00000100 EID-A Optional, 1=Accept Time Update Request
Pad 8 00000000 EID-A Mandatory
Application Data 48 Variable SCET=CUC time
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.8.3.3 Parameters
Time Value (PMRG0005) = CUC time, the time code format is 4 octets of unit seconds followed by two octets of fractional seconds
6.1.8.3.4 Execution Description
6.1.8.3.4.1 Actions Taken
The spacecraft elapsed time presented in this packet is used to update the instrument time reference on receipt of the following broadcast pulse.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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6.1.8.3.4.2 Resulting Effects
MIRO time-stamps each telemetry packet. The time value is furnished to a resolution of 1/65536 sec. MIRO maintains telemetry time stamping to an accuracy of better than 100 msec.
6.1.8.3.4.3 Additional Information
MIRO requires spacecraft time update once per hour. The MIRO software uses its internal real time clock (RTC) provided on the RAD6000 as the precision time source. The RTC is crystal driven and provides the accuracy required for the TM packet time stamping.
The interaction between the spacecraft provided time and the RTC works as follows. The MIRO software stores the spacecraft time internally upon receipt of the spacecraft time synch telecommand. When the follow-up TSY pulse is received the MIRO software resets the RTC time to zero. From that point forward the RTC will show the precise elapsed time since the spacecraft time was last received. All telemetry timestamps are calculated by adding the contents of the RTC registers to the last received spacecraft time to produce the current time.
MIRO software resynchs to the spacecraft time as often as the spacecraft sends out the time synch telecommand.
6.1.8.3.5 RSDB Inputs
Telecommand: ZMR00901 - Time Update
Parameters: PMRG0005 - Time Value
6.1.8.4 Connection Test Telecommand
6.1.8.4.1 Description
The objective of this command is to determine if MIRO is "alive". It tests the connection path from the spacecraft to the instrument.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.4.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 000000000000011 1 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Test service = 17
Packet Subtype 8 00000100 EID-A Optional, 1=Connection Test request
Pad 8 00000000 EID-A Mandatory
Application Data 0 Variable none
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.8.4.3 Parameters
None.
6.1.8.4.4 Execution Description
6.1.8.4.4.1 Actions Taken
When MIRO receives this request, it responds by generating a Connection Test Report (YMR00009) within 4 seconds if the following was completed successfully after start-up.
1.
Mirror driven to mechanical stop
2.
Mirror moved to space
3.
Time synch received or 60 seconds, whichever is first
4.
Turned on engineering telemetry collection.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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6.1.8.4.4.2 Resulting Effects
A connection test report is generated (YMR00009)
6.1.8.4.5 RSDB Inputs
Telecommand: ZMR01701 - Connection Test
6.1.8.5 Enable Science Telecommand
6.1.8.5.1 Description
This telecommand enables the output of science telemetry packets. Science telemetry packets are still generated as long as the instrument is in any mode other than engineering mode.
6.1.8.5.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Science Data Transfer=20
Packet Subtype 8 00000100 EID-A Optional, 1=Enable Science Report Generation (RTU-link)
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Pad field (9 bits)=0, PID (7bits=71)
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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6.1.8.5.3 Parameters
Process ID (PMRG0PID): Pad field (9bits)=0, PID (7 bits)=71(default)-the science report on which the operation acts is defined by the PID of the TM source application. For all MIRO science reports the PAD=0 and the PID=71.
6.1.8.5.4 Execution Description
6.1.8.5.4.1 Actions Taken
On receipt of this request, MIRO enables the outputting of science reports on the RTU link.
6.1.8.5.4.2 Resulting Effects
The transmission of Science telemetry (YMR00011) to the spacecraft is enabled.
6.1.8.5.5 RSDB Inputs Telecommand: ZMR02001 - Enable Science Parameters: PMRG0PID - Process ID
6.1.8.6 Disable Science Telecommand
6.1.8.6.1 Description
This telecommand disables the outputting of science telemetry packets to the spacecraft. Science telemetry packets are still generated as long as the instrument is in any mode other than engineering mode.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.6.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Science Data Transfer=20
Packet Subtype 8 00000100 EID-A Optional, 2=Disable Science Report Generation (RTU-link)
Pad 8 00000000 EID-A Mandatory
Application Data 16 Variable Pad field (9 bits)=0, PID (7bits=71)
Packet Error Control 16 Variable Telecommand Packet Checksum
6.1.8.6.3 Parameters
Process ID (PMRG0PID): Pad field (9bits)=0, PID (7 bits)=71(default)-the science report on which the operation acts is defined by the PID of the TM source application. For all MIRO science reports the PAD=0 and the PID=71.
6.1.8.6.4 Execution Description
6.1.8.6.4.1 Actions Taken
On receipt of this request, MIRO stops outputting of science reports on the RTU link. When the output of these science telemetry packets is disabled, the outbound fifo manager task drops all queued packets of that type on the floor the next time that it runs. It runs at 10 Hz.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.6.4.2 Resulting Effects
The transmission of Science telemetry (YMR00011) to the spacecraft is disabled.
6.1.8.6.5 RSDB Inputs Telecommand: ZMR02002 - Disable Science Parameters: PMRG0PID -Process ID
6.1.8.7 Reset Telemetry Telecommand
6.1.8.7.1 Description
If the telemetry stream from MIRO appears to be corrupted the DMS may issue this command as part of a telemetry recovery procedure.
6.1.8.7.2 Packet Definition
Data Element Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 1 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Sequence Flags 2 11 EID-A Mandatory
Sequence Count 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length 16 0000000000000111 This gets set to the size of the application data field (in bytes) + 5. In this case, 7.
PUS Version 3 000 EID-A Specified, Ground Sourced Telecommand
Checksum Flag 1 1 EID-A Mandatory
Ack 4 0001 EID-A Specified, Acknowledgement of Acceptance
Packet Type 8 11000000 EID-A Specified, Common Payload Telecommands = 255
Packet Subtype 8 00000100 EID-A Optional, 1=Reset Telemetry Output Buffer
Pad 8 00000000 EID-A Mandatory
Application Data 0 Variable none
Packet Error Control 16 Variable Telecommand Packet Checksum
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
6.1.8.7.3 Parameters
None
6.1.8.7.4 Execution Description
6.1.8.7.4.1 Actions Taken
The telemetry buffer is cleared.
6.1.8.7.4.2 Resulting Effects
The telemetry in the buffer is lost.
6.1.8.7.5 RSDB Inputs
Telecommand: ZMR25501 - Reset telemetry
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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DATA OPERATIONS HANDBOOK (TELEMETRY)
7.1 TELEMETRY
7.1.1 INTRODUCTION
The MIRO telemetry is downloaded in packets. Each packet has associated with it a
1.
Name
2.
Header information including Packet Type and Subtype,
3.
Format, and
4.
Parameters. The MIRO Telemetry Packets are given in the table below.
Packet Name Type Sub Type Type Name Subtype Name RSDB Name
Accept Success 1 1 Telecommand Verification Acceptance Success Report YMRST001
Incomplete Packet 1 2 Telecommand Verification Acceptance Failure Report YMRST002
Incorrect Checksum 1 2 Telecommand Verification Acceptance Failure Report YMRST003
Incorrect APID 1 2 Telecommand Verification Acceptance Failure Report YMRST004
Invalid Command Code 1 2 Telecommand Verification Acceptance Failure Report YMRST005
MIRO Housekeeping Data 3 25 Housekeeping Data Housekeeping Parameter Report YMR00001
MIRO On 5 1 Event Reporting Normal Progress Report YMR00012
Asteroid Mode Started 5 1 Event Reporting Normal Progress Report YMR00013
Asteroid Mode Completed 5 1 Event Reporting Normal Progress Report YMR00014
Mirror Error Type 1 5 2 Event Reporting Warning Anomalous Event Report YMR00002
Mirror Error Type 2 5 2 Event Reporting Warning Anomalous Event Report YMR00003
Mirror Error Type 3 5 2 Event Reporting Warning Anomalous Event Report YMR00004
Mirror Error Type 4 5 3 Event Reporting Ground Action Anomalous Event Report YMR00005
Mirror Error Type 5 5 3 Event Reporting Ground Action Anomalous Event Report YMR00006
CTS Error 5 3 Event Reporting Ground Action Anomalous Event Report YMR00015
Memory Dump 6 6 Memory Management Memory Dump Report YMR00007
Memory Checksum 6 10 Memory Management Memory Check Report YMR00008
Connection Report 17 2 Test Service Connection Test Report YMR00009
Spectroscopic (CTS) Science 20 3 Science Data Science Data Report YMR00011
Submillimeter Continuum Science 20 3 Science Data Science Data Report YMR00011
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Packet Name Type Sub Type Type Name Subtype Name RSDB Name
Millimeter Continuum Science 20 3 Science Data Science Data Report YMR00011
Miscellaneous Science 20 3 Science Data Science Data Report YMR00011
7.1.2 HOUSEKEEPING DATA TELEMETRY
7.1.2.1 Description
The MIRO housekeeping data contains engineering data including temperatures, voltages, and currents.
The housekeeping data packets are generated whenever the instrument is turned on in any mode. It is nominally generated every 11.2 seconds. If the housekeeping skip command is executed, the generation time can be set to multiples of 11.2 sec.
7.1.2.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 0100 EID-A Specified, Housekeeping = 4
Segmentation Flags NMRDH141 2 11 EID-A Mandatory
Source Sequence Count NMRDH142 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH142 16 10001001 This gets set to the size of the source data field (in bytes) + 9. This is 137 bytes.
Time NMRAH143 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH145 3 010 EID-A Specified, Non-science data
Checksum Flag NMRDH146 1 0 EID-A Mandatory
Spare NMRDH147 4 0000 EID-A Mandatory
Packet Type NMRDH148 8 00000011 EID-A Specified, Table 2.8.2-1, Housekeeping Reporting = 3
Packet Subtype NMRDH149 8 00011001 EID-A Specified, Housekeeping Parameter Report = 25
Pad NMRDH140 8 00000000 EID-A Specified
Source Data 1024 128 bytes Detailed definition on following page.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Engineering Source Data Definition
Data Field # RSDB Parameter Reference
Data Size (bits)
Function
1 NMRA0001 8 Pad
1 NMRA0001 8 SID, value = 1
2 NMRA0002 16 Operational Mode
3 NMRA0003 16 SUCR bits 0-15*
4 NMRA0004 16 SUCR bits 16-31*
5 NMRA0005 16 Address 100 bits 8-15 (in LSBs)*
6 NMRA0006 16 Mirror Location: 1=sky, 2=hot, 3=cold
7 NMRA0064 16 Reserved
8 NMRA0065 16 Reserved
Data Field # RSDB Parameter Reference EU Channel No. Data Size (bits) Signal Name Function
9 NMRA0009 0 16 T_BRANCHA1 CTS Temp. Sensor 1 Branch A
10 NMRA0010 1 16 T_BRANCHA2 CTS Temp. Sensor 2 Branch A
11 NMRA0011 2 16 T_BRANCHB1 CTS Temp. Sensor 1 Branch B
12 NMRA0012 3 16 T_BRANCHB2 CTS Temp. Sensor 2 Branch B
13 NMRA0013 4 16 T_ANATRAY1 CTS Temp. Sensor 1 Ana. Tray
14 NMRA0014 5 16 T_ANATRAY2 CTS Temp. Sensor 2 Ana. Tray
15 NMRA0007 6 16 EU-TEMP Electronics Unit Temperature
16 NMRA0008 7 16 ECAL-TEMP Reference Temp (634 ohms)
17 NMRA0015 16 16 +5V-LO +5V Voltage Monitor
18 NMRA0016 17 16 +12V-LO +12V Voltage Monitor
19 NMRA0017 18 16 -12V-LO -12V Voltage Monitor
20 NMRA0018 19 16 +3.3VLO +3.3V Voltage Monitor
21 NMRA0020 20 16 +24V-LO +24V Voltage Monitor
22 NMRA0019 21 16 +5VANA-LO +5V Ana. Voltage Monitor
23 NMRA0021 22 16 +5VI-LO +5V Current Monitor
24 NMRA0022 23 16 +12VI-LO +12V Current Monitor
25 NMRA0023 24 16 -12VI-LO -12V Current Monitor
26 NMRA0026 25 16 +24VANAI-LO +24V Current Monitor
27 NMRA0024 26 16 +3.3VI-LO +3.3V Current Monitor
28 NMRA0025 27 16 +5VANAI-LO +5V Ana. Current Monitor
29 NMRA0027 28 16 TLM-HEATING USO Temp Status
30 NMRA0028 29 16 TLM-RF USO RF Power Status
31 NMRA0029 30 16 HVPG1 CTS PG1 Voltage
32 NMRA0030 31 16 HVPG2 CTS PG2 Voltage
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Engineering Source Data Definition (continued)
Data Field # RSDB Parameter Reference SU Channel No. Data Size (bits) Signal Name Function
33 NMRA0031 0 16 COLD-LOAD1 Cold Load Temperature # 1
34 NMRA0032 1 16 COLD-LOAD2 Cold Load Temperature # 2
35 NMRA0033 2 16 WARM-LOAD1 Warm Load Temperature #1
36 NMRA0034 3 16 O/B Optical Bench Temperature
37 NMRA0035 4 16 TELESCOPE-1 Telescope # 1 Temperature
38 NMRA0036 5 16 TELESCOPE-2 Telescope # 2 Temperature
39 NMRA0037 6 16 PLL-T Phase Lock Loop Temperature
40 NMRA0038 7 16 IFP-DET-T smm IF Processor Detector Temperature
41 NMRA0039 8 16 IFP-AMP-T smm IF Processor Amplifier Temperature
42 NMRA0040 9 16 SMM-LO-GUNN smm Lo Gunn Temperature
43 NMRA0041 10 16 MM-LO-GUNN mm Lo Gunn Temperature
44 NMRA0042 11 16 MOTOR Mirror Motor Temperature
45 NMRA0043 12 16 SEN-EL Sensor Electronics Temperature
46 NMRA0044 13 16 WARM-LOAD2 Warm Load Temperature # 2
47 NMRA0045 14 16 CAL-TEMP-LO Reference Temperature (191 ohms)
48 NMRA0046 15 16 CAL-TEMP-HI Reference Temperature (681 ohms)
49 NMRA0047 16 16 +5V-LO +5v Voltage Monitor
50 NMRA0048 17 16 +12V-1-LO +12v Voltage Monitor # 1
51 NMRA0050 18 16 +12V-2-LO +12v Voltage Monitor # 2
52 NMRA0049 19 16 -12V-LO -12v Voltage Monitor
53 NMRA0051 20 16 +5VI-LO +5v Current Monitor
54 NMRA0052 21 16 +12VI-1-LO +12v Current Monitor # 1
55 NMRA0054 22 16 +12VI-2-LO +12v Current Monitor # 2
56 NMRA0053 23 16 -12VI-LO -12v Current Monitor
57 NMRA0059 24 16 MM-GUNN-I mm Gunn Current Status
58 NMR0061 (no data) 25 16 SMM-MULT smm Multiplier Current Status
59 NMRA0055 26 16 SMM-PLL-ERR Static Phase Error for smm PLL
60 NMRA0056 27 16 FS1-ERR Phase Error for Freq Synthesizer # 1
61 NMRA0057 28 16 FS2-ERR Phase Error for Freq Synthesizer # 2
62 NMR0058 29 16 FS3-ERR Phase Error for Freq Synthesizer # 3
63 NMRA0060 30 16 SMM-PLLGUNN-I smm Gunn Current Status (Via PLL)
64 Reserved 31 16 Reserved
*See following tables for identification of bits
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Address Bit Assignments
ADDR Start ADDR End Bit No. RSDB NMRA0005 BIT No. Type Function
0100 01FF 0* Output Select EMUX 0
0100 01FF 1* Output Select EMUX 1
0100 01FF 2* Output Select EMUX 2
0100 01FF 3* Output Select EMUX 3
0100 01FF 4* Output Select EMUX 4
0100 01FF 5* Output Send CMD REG Data to SU
0100 01FF 6* Output Enable motor stepping
0100 01FF 7 Output Load enable (1=enable, 0=disable)
0100 01FF 8* 15 Output +12V SPEC On (0=off, 1=on)
0100 01FF 9* 14 Output +5V SPEC On (0=off, 1=on)
0100 01FF 10* 13 Output +5V ANA SPEC On (0=off, 1=on)
0100 01FF 11* 12 Output +3.3V SPEC On (0=off, 1=on)
0100 01FF 12* 11 Output -12V SPEC On (comes on when +12V SPEC is On) (0=off, 1=on)
0100 01FF 13* 10 Output +24V USO On (0=off, 1=on)
0100 01FF 14* 9 Output CAL HTR On (0=off, 1=on)
0100 01FF 15* 8 Output CTS Tri-state: 1=disable, 0=Enable**
0200 02FF 0* Output ST CONV EU (Initially HI, LO-HI to start)
0200 02FF 1* Output ST CONV SU (initially HI, LO-HI to start)
0200 02FF 2* Output ST Continuum period (Initially HI, LO-HI to start)
0200 02FF 3* Output Continuum select (0=5ms, 1=100 ms)
0200 02FF 4* Output Motor speed select (0=100Hz, 1=500 Hz)
0200 02FF 5* Output ST Acquisition of SU Status
0200 02FF 6* Output Reset SMD FIFO (Initially HI, LO-HI to reset)
0200 02FF 7* Output Reset Data FIFO (initially HI, LO-HI to reset)
0200 02FF 8-15 Output Unassigned
0300 03ff 0-15 Input SU Status Register Bits 33-48 (mm cont.)
0400 04FF 0-15 Input SU Status Register Bits 49-64 (smm cont.)
0500 05FF 0-15 Input SU Status Register Bits 1-16
0600 06FF 0-15 Input SU Status Register Bits 17-32
0700 07FF 0-15 Output SU Control Register Bits 1-16
0800 08FF 0-15 Output SU Control Register Bits 17-32
*Low edge triggers, H/W initiates it low, I will initiate it HI in S/W, to toggle I will go LO-HI **In FM S/W Code: Initially enabled, disabled after CTS powered on, enabled by turning off CTS power.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Sensor Unit Control Register (SUCR) Bit Assignments
Bit # RSDB TM RSDB Bit No. Name Description
0 NMRA0003 15 Hskp_Mux0 Selects housekeeping channel
1 NMRA0003 14 Hskp_Mux1 Selects housekeeping channel
2 NMRA0003 13 Hskp_Mux2 Selects housekeeping channel
3 NMRA0003 12 Hskp_Mux3 Selects housekeeping channel
4 NMRA0003 11 Hskp_Mux4 Selects housekeeping channel
5 NMRA0003 10 Pwr_Contl_Non-5VSMM Commands +5V, +/-12V on after -5V is commanded using smm cont. mode
6 NMRA0003 9 IFP_Contl1 Bit 0 of IFP Power Control
7 NMRA0003 8 IFP_Contl2 Bit 1 of IFP Power Control
8 NMRA0003 7 MM_LNA_On Powers on MM LNA Bias (0=on, 1=off)
9 NMRA0003 6 SMM_LNA_On Powers on SMM LNA Bias (0=on, 1=off)
10 NMRA0003 5 Pwr_Contl_Non-5VMM Commands +5V, +/-12V on after -5V is commanded on using mm cont. mode
11 NMRA0003 4 Pwr_Contl_Non-5VSPEC Commands +5V, +/-12V on after -5V is commanded on using SPEC mode.
12 NMRA0003 3 Loop Reset Phase-lock Reset (0 locks, 1 unlocks)
13 NMRA0003 2 IFP_Contl3 Bit 2 of IFP Power Control
14 NMRA0003 1 IFP_Contl4 Bit 3 of IFP Power Control
15 NMRA0003 0 Not used 0
16 NMRA0004 15 Set_smm_GO0 Sets bit for voltage to smm Gunn Osc (LSB)
17 NMRA0004 14 Set_smm_GO1 Sets bit for voltage to smm Gunn Osc
18 NMRA0004 13 Set_smm_GO2 Sets bit for voltage to smm Gunn Osc
19 NMRA0004 12 Set_smm_GO3 Sets bit for voltage to smm Gunn Osc (MSB)
20 NMRA0004 11 Not used 0
21 NMRA0004 10 Not used 0
22 NMRA0004 9 Not used 0
23 NMRA0004 8 Not used 0
24 NMRA0004 7 Set_pwr_mode0 Sets -5V for smm cont. mode
25 NMRA0004 6 Set_pwr_mode1 Sets -5V for mm cont. mode
26 NMRA0004 5 Set_pwr_mode2 Sets -5V for spec. mode
27 NMRA0004 4 Load_freq Loads the (3) frequency synthesizer chips (set and clear to load)
28 NMRA0004 3 Mirror_pwr_ON Sets mirror power on (0=on, 1=off)
29 NMRA0004 2 Mirror_dir Sets mirror direction to forward (0=forward, 1=backward)
30 NMRA0004 1 Set_Freq_V- Sets smm frequency switched state (+/-5MHz)
31 NMRA0004 0 Pin_Puller-On Activate pin puller (set and clear to activate)
Note: This data moved into engineering HK packet when packet has been filled with data. Reflects settings at about
11.2 seconds after the packet time stamp.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.2.3 Expected Values
The expected values given below were measured during the MIRO thermal Vacuum Tests conducted at JPL prior to integration of the instrument onto the Rosetta spacecraft. The first table contains housekeeping data for when the instrument was cold, -20 C.
The second table contains housekeeping data with the instrument in different modes for when the instrument interface for the EU was 55 C and SU 40 C.
Values measured when instrument was "Cold" (Interfaces at about -20 C)
Mode/Housekeeping Parameter Eng Eng -Cal Heat On Eng -USO On Eng -Warmed Up Eng -Cal Heat Off Eng -USO Off MM Cont SMM Cont Dual Cont Dual Cont -CTS WarmUp, Power Hi Dual Cont -CTS WarmUp Power Lo Dual Cont-CTS Warm Up Off CTS/ SMM CTS/ SMM -CTS HeaterOn, Power Lo CTS/ SMM-CTS HeaterPower LO, finished CTS/ Dual
Spect T1 [C] -5.78 -6.08 -6.31 -9.73 -9.90 -10.03 -10.40 -10.63 -10.86 -10.96 -9.93 -8.90 -9.27 -8.20 -0.17 -0.30
Spect T2 [C] -5.62 -5.95 -6.19 -9.63 -9.79 -9.93 -10.32 -10.52 -10.75 -10.85 -9.36 -9.03 -9.30 -9.30 -0.68 -0.55
Spect T3 [C] -5.65 -5.94 -6.18 -9.60 -9.77 -9.90 -10.30 -10.53 -10.73 -10.87 -9.77 -8.74 -9.20 -9.10 -0.01 -0.15
Spect T4 [C] -5.69 -6.03 -6.26 -9.67 -9.84 -9.97 -10.37 -10.60 -10.80 -10.93 -9.47 -9.11 -9.34 -9.37 -0.78 -0.65
Spect T5 [C] -20.82 -20.83 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.82 -20.87 -20.83 -20.82
Spect T6 [C] -16.56 -16.79 -16.99 -18.31 -18.31 -18.34 -18.41 -18.47 -18.54 -18.57 -18.31 -18.08 -17.55 -17.42 -14.94 -14.77
EU Temp [C] -6.98 -7.15 -7.25 -6.19 -6.26 -6.32 -6.59 -6.82 -7.02 -7.15 -7.05 -6.95 -6.16 -5.86 -3.24 -3.14
Ecal Temp [DN] 2600 2601 2601 2601 2601 2599 2598 2599 2601 2600 2601 2602 2602 2600 2602 2602
+5V EU [V] 5.17 5.17 5.17 5.17 5.17 5.17 5.17 5.17 5.17 5.11 5.11 5.11 5.08 5.08 5.08 5.08
+12V EU [V] 12.58 12.58 12.58 12.58 12.58 12.58 12.58 12.58 12.59 11.97 12.21 13.09 13.20 12.29 13.06 12.82
-12V EU [V] -12.57 -12.57 -12.57 -12.57 -12.58 -12.56 -12.56 -12.56 -12.57 -12.66 -12.65 -13.10 -13.22 -12.75 -13.14 -13.01
+3.3V EU [V] 3.31 3.31 3.31 3.31 3.31 3.31 3.31 3.31 3.31 3.37 3.37 3.37 3.44 3.44 3.44 3.44
+24V EU [V] 23.37 25.12 23.66 24.58 24.21 24.21 23.38 23.39 23.39 26.11 26.11 26.11 23.75 23.75 24.14 24.14
+5V Ana EU [V] 5.22 5.21 5.21 5.21 5.21 5.21 5.22 5.22 5.22 5.10 5.10 5.10 5.10 5.10 5.10 5.10
+5V Curr EU [A] 0.54 0.54 0.54 0.56 0.54 0.54 0.54 0.54 0.55 1.46 1.47 1.47 2.08 2.06 2.07 2.08
+12V Curr EU [A] 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.51 0.31 0.07 0.07 0.31 0.10 0.14
-12V Curr EU [A] 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.07 0.07 0.07 0.07 0.07 0.07 0.07
+24V Curr EU [A] 0.02 0.05 0.45 0.09 0.17 0.17 0.02 0.02 0.02 0.02 0.02 0.02 0.38 0.38 0.17 0.17
+3.3V Curr Eu [A] 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.66 0.67 0.66 1.33 1.35 1.33 1.34
+5V Ana Curr EU [A] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.42 0.42 0.42 0.43 0.43 0.43 0.43
TLM Heating [V] 0.01 0.01 1.35 0.78 0.97 0.97 0.01 0.01 0.01 0.01 0.01 0.01 1.30 1.30 0.97 0.97
TLM RF [V] 0.01 0.01 0.05 0.03 0.03 0.03 0.01 0.01 0.01 0.01 0.01 0.01 0.05 0.05 0.03 0.03
CTS V Ana 1 [V] 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 2.46 2.47 2.47 2.45 2.45 2.46 2.46
CTS V Ana 2 [V] 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 2.47 2.48 2.48 2.46 2.46 2.47 2.47
Cold Load 1 Temp [C] -46.97 -47.12 -47.20 -47.50 -47.42 -47.35 -47.35 -47.42 -47.42 -47.42 -47.50 -47.50 -47.64 -47.64 -48.02 -48.10
Cold Load 2 Temp [C] -46.50 -46.65 -46.73 -46.95 -46.95 -46.80 -46.88 -46.95 -46.95 -46.95 -46.95 -46.95 -47.17 -47.17 -47.55 -47.55
Warm Load 1 Temp [C] 6.38 6.45 8.17 20.24 20.16 19.26 16.94 15.65 14.54 14.01 13.41 12.96 11.54 11.17 7.38 6.98
Warm Load 2 Temp [C] 6.36 6.44 8.08 20.20 20.13 19.28 16.90 15.63 14.51 13.98 13.39 12.94 11.52 11.14 7.26 6.96
Telescope1 Temp [C] 16.27 16.27 16.20 15.82 15.82 15.75 15.75 15.75 15.67 15.67 15.67 15.67 15.59 15.59 15.37 15.29
Telescope2 Temp [C] 17.38 17.31 17.31 16.86 16.86 16.79 16.79 16.71 16.71 16.71 16.64 16.64 16.56 16.56 16.34 16.34
PLL Temp [C] -16.23 -16.38 -16.53 -18.45 -18.53 -18.60 -18.75 -16.16 -14.09 -13.42 -12.90 -12.53 -11.50 -11.20 -8.38 -8.23
IFP Det Temp [C] -19.54 -19.76 -19.99 -21.72 -21.72 -21.80 -21.80 -21.65 -21.50 -21.35 -21.27 -21.19 -20.67 -20.52 -19.16 -19.01
IFP Amp Temp [C] -18.70 -18.92 -19.07 -20.84 -20.92 -20.92 -20.99 -20.84 -20.70 -20.62 -20.47 -20.40 -19.73 -19.59 -18.26 -18.11
SMM LO Gunn Temp [C] -21.74 -21.81 -21.81 -21.89 -21.89 -21.89 -21.89 -20.02 -18.68 -18.08 -17.63 -17.18 -16.28 -16.13 -15.54 -15.69
MM LO Gunn Temp [C] -21.07 -21.07 -21.07 -21.15 -21.15 -21.07 -19.87 -19.65 -18.20 -18.45 -17.92 -17.47 -18.15 -18.60 -20.32 -19.57
Motor Temp [C] -19.89 -19.89 -19.89 -20.04 -20.04 -20.04 -17.13 -16.02 -15.20 -16.24 -16.99 -17.43 -15.79 -16.54 -18.33 -16.32
Sensor Elect. Temp [C] -13.00 -13.14 -13.29 -15.16 -15.24 -15.31 -15.38 -15.38 -15.31 -15.24 -15.09 -15.01 -14.71 -14.56 -13.29 -13.14
Optical Bench Temp [C] -20.05 -20.05 -20.05 -20.12 -20.12 -20.12 -20.05 -19.82 -19.38 -19.08 -18.85 -18.56 -18.03 -17.88 -18.18 -16.33
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Mode/Housekeeping Parameter Eng Eng -Cal Heat On Eng -USO On Eng -Warmed Up Eng -Cal Heat Off Eng -USO Off MM Cont SMM Cont Dual Cont Dual Cont -CTS WarmUp, Power Hi Dual Cont -CTS WarmUp Power Lo Dual Cont-CTS Warm Up Off CTS/ SMM CTS/ SMM -CTS HeaterOn, Power Lo CTS/ SMM-CTS HeaterPower LO, finished CTS/ Dual
Cal Temp Low [DN] 491 491 491 492 491 491 491 491 492 492 492 491 491 491 492 491
Cal Temp High [DN] 3735 3734 3735 3735 3735 3735 3735 3735 3735 3735 3735 3735 3735 3735 3735 3735
+5V SBEU [V] 5.17 5.17 5.17 5.17 5.17 5.17 5.14 5.14 5.11 5.11 5.11 5.11 4.99 4.99 4.98 4.96
+12V-1 SBEU [V] 12.35 12.35 12.35 12.35 12.35 12.35 12.35 12.35 12.47 12.47 12.47 12.47 12.03 12.03 12.03 12.05
+12V-2 SBEU [V] 12.00 12.00 12.00 12.00 12.00 12.01 11.92 11.92 11.84 11.84 11.84 11.84 11.92 11.92 11.92 11.84
-12V SBEU [V] -12.59 -12.59 -12.59 -12.59 -12.59 -12.59 -12.69 -12.64 -12.77 -12.77 -12.77 -12.77 -12.18 -12.18 -12.17 -12.19
+5V Curr SBEU [A] 0.12 0.12 0.12 0.12 0.12 0.12 0.30 0.29 0.46 0.46 0.46 0.46 1.14 1.14 1.14 1.29
+12V Curr1 SBEU [A] 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.45 0.45 0.45 0.45
+12V Curr2 SBEU [A] 0.01 0.01 0.01 0.01 0.01 0.01 0.32 0.37 0.68 0.68 0.68 0.68 0.37 0.37 0.37 0.68
-12V Curr SBEU [A] 0.08 0.08 0.08 0.08 0.08 0.08 0.09 0.13 0.14 0.14 0.14 0.14 0.17 0.16 0.16 0.17
MM Gunn Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 148.6 0.00 148.7 148.9 148.9 149.0 0.00 0.00 0.00 148.6
SMM Mult Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
SMM PLL ERR [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.22 0.23 0.22 0.23 0.23 2.60 2.58 2.54 2.53
FS1 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.62 1.62 1.66 1.66
FS2 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.68 1.68 1.71 1.71
FS3 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.53 1.54 1.59 1.59
SMM PLL Gunn Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 0.13 123.6 124.0 124.2 124.4 124.5 121.8 121.8 122.1 122.0
Values measured wheninstrument was "Hot" (EU interface at about 55 C, Optical Bench at about 40 C)
Mode/Housekeeping Parameter Eng Eng -Cal Heat On Eng -USO On Eng -Warmed Up Eng -Cal Heat Off Eng -USO Off MM Cont SMM Cont Dual Cont Dual Cont -CTS WarmUp, Power Hi Dual Cont -CTS WarmUp Power Lo Dual Cont-CTS Warm Up Off CTS/ SMM CTS/ SMM -CTS HeaterOn, Power Lo CTS/ SMM-CTS HeaterPower LO, finished CTS/ Dual
Spect T1 [C] 67.56 66.88 66.37 66.21 65.75 65.48 65.11 64.83 64.42 65.79 64.63 67.53 66.64 66.69 68.31
Spect T2 [C] 67.77 67.16 66.64 66.51 66.07 65.76 65.39 65.11 64.71 66.44 65.25 67.23 66.78 68.28 68.38
Spect T3 [C] 67.67 66.98 66.47 66.33 65.89 65.62 65.24 64.97 64.52 65.96 64.76 67.67 66.71 68.83 68.39
Spect T4 [C] 67.69 67.07 66.56 66.43 65.98 65.71 65.34 65.06 64.62 66.26 65.10 67.14 66.73 68.20 68.30
Spect T5 [C] 60.84 56.81 56.75 56.78
Spect T6 [C] 55.15 54.41 53.73 53.83 53.19 53.29 52.74 52.58 52.17 52.34 52.13 52.68 53.63 54.41 54.98
EU Temp [C] 57.84 57.00 56.62 56.52 56.28 56.08 55.81 55.57 55.27 55.27 55.13 55.51 56.39 57.44 57.94
Ecal Temp [DN] 2625 2625 2625 2625 2624 2625 2625 2624 2624 2623 2623 2625 2626 2626 2626
+5V EU [V] 5.16 5.16 5.16 5.16 5.16 5.16 5.16 5.16 5.16 5.10 5.10 5.10 5.09 5.05 5.05
+12V EU [V] 12.43 12.44 12.44 12.43 12.44 12.43 12.44 12.46 12.46 12.03 11.80 12.96 13.09 12.96 12.77
-12V EU [V] -12.34 -12.37 -12.35 -12.35 -12.35 -12.35 -12.38 -12.36 -12.37 -12.47 -12.56 -12.90 -13.04 -12.97 -12.87
+3.3V EU [V] 3.32 3.32 3.32 3.32 3.32 3.32 3.32 3.32 3.32 3.38 3.38 3.38 3.49 3.47 3.46
+24V EU [V] 23.03 24.87 23.56 24.28 24.83 23.03 23.03 23.02 23.02 25.79 25.79 25.81 24.76 24.76 24.76
+5V Ana EU [V] 5.22 5.21 5.21 5.21 5.21 5.22 5.22 5.22 5.22 5.07 5.07 5.07 5.07 5.07 5.07
+5V Curr EU [A] 0.51 0.51 0.51 0.54 0.51 0.51 0.53 0.52 0.54 1.49 1.48 1.48 2.09 2.12 2.10
+12V Curr EU [A] 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.32 0.52 0.07 0.08 0.09 0.13
-12V Curr EU [A] 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.07 0.07 0.07 0.07
+24V Curr EU [A] 0.02 0.05 0.28 0.10 0.06 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.06 0.06 0.06
+3.3V Curr Eu [A] 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.55 0.55 0.54 1.27 1.27 1.26
+5V Ana Curr EU [A] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.46 0.46 0.46 0.46 0.46 0.46
TLM Heating [V] 0.01 0.01 1.04 0.79 0.79 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.79 0.79 0.79
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Mode/Housekeeping Parameter Eng Eng -Cal Heat On Eng -USO On Eng -Warmed Up Eng -Cal Heat Off Eng -USO Off MM Cont SMM Cont Dual Cont Dual Cont -CTS WarmUp, Power Hi Dual Cont -CTS WarmUp Power Lo Dual Cont-CTS Warm Up Off CTS/ SMM CTS/ SMM -CTS HeaterOn, Power Lo CTS/ SMM-CTS HeaterPower LO, finished CTS/ Dual
TLM RF [V] 0.01 0.01 0.03 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02
CTS V Ana 1 [V] 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 2.54 2.54 2.54 2.48 2.48 2.48
CTS V Ana 2 [V] 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 2.54 2.54 2.54 2.48 2.48 2.48
Cold Load 1 Temp [C] -29.48 -28.73 -28.43 -28.50 -29.03 -29.10 -28.95 -28.80 -29.18 -29.33 -29.40 -29.10 -28.65 -29.33 -30.00
Cold Load 2 Temp [C] -28.97 -28.22 -27.92 -27.92 -28.45 -28.52 -28.37 -28.30 -28.67 -28.75 -28.82 -28.60 -28.15 -28.75 -29.42
Warm Load 1 Temp [C] 49.01 48.56 48.78 48.78 48.78 46.89 44.61 43.02 40.98 38.86 39.46 37.80 36.14 34.55 33.57
Warm Load 2 Temp [C] 48.93 48.47 48.70 48.70 48.70 46.81 44.54 42.95 40.91 38.79 39.47 37.81 36.15 34.57 33.51
Telescope1 Temp [C] 23.08 23.08 23.08 23.08 23.08 23.08 23.08 23.08 23.08 23.00 23.00 23.00 23.00 23.00 22.93
Telescope2 Temp [C] 23.66 23.66 23.74 23.66 23.74 23.66 23.74 23.66 23.66 23.68 23.66 23.66 23.66 23.59 23.59
PLL Temp [C] 56.46 54.72 53.97 53.74 53.29 52.99 52.76 53.74 57.14 58.20 57.97 58.43 58.96 59.79 60.32
IFP Det Temp [C] 55.84 55.15 54.76 54.69 54.38 54.22 54.15 54.22 54.30 54.46 54.38 54.53 54.92 55.30 55.69
IFP Amp Temp [C] 55.56 54.88 54.43 54.28 54.05 53.90 53.75 53.82 53.90 54.05 53.97 54.05 54.58 55.03 55.34
SMM LO Gunn Temp [C] 43.71 42.41 41.64 41.26 40.96 40.65 40.27 42.26 43.33 44.32 44.02 44.63 45.01 44.93 44.78
MM LO Gunn Temp [C] 45.88 44.80 44.11 43.81 43.50 43.27 44.04 43.81 44.04 45.50 45.19 45.80 44.19 42.73 43.58
Motor Temp [C] 45.14 44.76 44.30 44.07 43.77 43.54 44.84 44.84 45.37 43.54 43.92 43.16 44.23 43.01 44.15
Sensor Elect. Temp [C] 59.09 58.24 57.63 57.32 57.09 56.86 56.56 56.48 56.48 56.63 56.56 56.71 56.94 57.17 57.55
Optical Bench Temp [C] 45.22 44.31 43.70 43.39 43.09 42.86 42.55 42.55 42.78 43.16 43.09 43.39 43.54 43.32 43.16
Cal Temp Low [DN] 487.0 487.0 487.0 487.0 487.0 487.0 487.0 487.0 487.0 486.0 486.0 487.0 487.0 487.0 486.0
Cal Temp High [DN] 3730 3731 3731 3731 3731 3731 3731 3731 3731 3731 3731 3731 3731 3731 3731
+5V SBEU [V] 5.17 5.18 5.17 5.18 5.17 5.17 5.13 5.14 5.09 5.09 5.09 5.09 4.93 4.93 4.89
+12V-1 SBEU [V] 12.23 12.23 12.23 12.23 12.23 12.24 12.31 12.24 12.38 12.37 12.37 12.37 11.89 11.89 11.91
+12V-2 SBEU [V] 12.04 12.03 12.04 12.04 12.03 12.03 11.94 11.93 11.84 11.84 11.84 11.84 11.93 11.93 11.84
-12V SBEU [V] -12.42 -12.43 -12.43 -12.43 -12.43 -12.43 -12.52 -12.48 -12.61 -12.61 -12.61 -12.61 -11.95 -11.94 -11.98
+5V Curr SBEU [A] 0.14 0.14 0.14 0.14 0.14 0.14 0.33 0.31 0.50 0.50 0.50 0.50 1.20 1.20 1.35
+12V Curr1 SBEU [A] 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.48 0.48 0.48
+12V Curr2 SBEU [A] 0.01 0.01 0.01 0.01 0.01 0.01 0.34 0.40 0.73 0.73 0.73 0.73 0.40 0.40 0.73
-12V Curr SBEU [A] 0.08 0.08 0.08 0.08 0.08 0.08 0.09 0.13 0.15 0.15 0.15 0.15 0.16 0.16 0.18
MM Gunn Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 157.3 0.00 157.3 157.3 157.3 157.4 0.00 0.00 157.1
SMM Mult Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
SMM PLL ERR [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.29 0.29 0.29 0.29 0.29 2.29 2.25 2.21
FS1 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.70 2.71 2.71
FS2 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.41 2.42 2.42
FS3 Err [V] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.67 2.69 2.70
SMM PLL Gunn Curr [mA] 0.00 0.00 0.00 0.00 0.00 0.00 0.06 145.4 145.8 145.1 146.1 146.2 144.9 145.1 144.9
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Graphs of selected engineering housekeeping data as a function of instrument mode for the "Cold" and "Hot" Measurements.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
7.1.2.4 Calibration
7.1.2.4.1 Temperature Calibration
There are 21 Platinum Resistance Thermistors (PRT) in the MIRO instrument. The tables below provide both a second order and first order polynomial fit for the temperature as a function of raw data number for each PRT. The MIRO EGSE uses the second order fit. It provides the higher accuracy necessary to meet the temperature accuracy requirements. The 1st order fit is used by the Rosetta Data system to provide calibrated temperatures. The RSDB calibration data is used by ESA at download time to determine if an "out-of-limit" condition is met. This does not require the same degree of accuracy as the scientific use of the data.
EGSE 2nd order polynomial fit of temperature as a function of raw data number (DN).
PRT S/N PRT Location Subsys T[N] Coefficient A T[N] Coefficient B T[N] Coefficient C Max. Residual Error [C]
[C/DN2] [C/DN] [C]
PE40 Spect 1 (T_BRANCHA1) EU 2.07883E-07 3.30314E-02 -19.726 0.078
PE41 Spect 2 (T_BRANCHA2) EU 2.08406E-07 3.29487E-02 -20.227 0.077
PE53 Spect 3 (T_BRANCHB1) EU 2.09061E-07 3.31136E-02 -19.123 0.072
PE55 Spect 4 (T_BRANCHB2) EU 2.07419E-07 3.29994E-02 -19.888 0.072
PE44 Spect 5 (T_ANATRAY1) EU 2.06196E-07 3.28688E-02 -20.823 0.076
PE62 Spect 6 (T_ANATRAY2) EU 2.04410E-07 3.30287E-02 -20.060 0.065
JF72 EU TEMP EU 2.10070E-07 3.28850E-02 -20.666 0.091
YK64 COLD-LOAD1 TEMP SU 9.04375E-07 7.08852E-02 -182.322 0.004
YK68 COLD-LOAD2 TEMP SU 9.05168E-07 7.13410E-02 -181.954 0.003
YG80 WARM-LOAD1 TEMP SU 1.04532E-06 6.92694E-02 -181.685 0.346
YK69 WARM-LOAD2 TEMP SU 1.03268E-06 6.92212E-02 -181.714 0.299
JF54 O/B TEMP SU 1.08622E-06 6.96198E-02 -182.487 0.09
JF73 TELESCOPE-1 TEMP SU 1.14824E-06 6.92175E-02 -182.003 0.268
LS46 TELESCOPE-2 TEMP SU 1.07134E-06 6.86548E-02 -183.325 0.542
LS54 PLL-TEMP (S/N 02) SBEU 8.26760E-07 7.01107E-02 -185.042 0.006
YK62 IFP-DET-T (smm) TEMP (SN02) SBEU 8.79567E-07 6.99528E-02 -183.799 0.003
YK60 IFP-AMP-T (mm) TEMP (SN02) SBEU 8.91920E-07 7.13595E-02 -183.029 0.004
LS41 SMM-LO-GUNN TEMP (SN02) SU 8.51491E-07 7.02587E-02 -184.653 0.004
HZ55 MM-LO-GUNN TEMP (SN02) SU 1.05513E-06 7.02858E-02 -182.608 0.064
JF57 MIRROR MOTOR TEMP SU 1.08123E-06 6.95330E-02 -182.631 0.088
JF70 SEN-EL TEMP SBEU 1.06962E-06 6.96692E-02 -182.699 0.083
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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RSDB Linear fit of temperature as a function of raw data number
PRT S/N PRT Location Subsys RSDB Name T[N] Coefficient m [C/DN] T[N] Coefficient b [C] Max Error at DN=0 [C] Error at Dnmax [C]
PE40 Spect 1 (T_BRANCHA1) EU CMRY0100 0.033883675 -20.29413482 0.57 0.56
PE41 Spect 2 (T_BRANCHA2) EU CMRY0101 0.033803149 -20.79651699 0.57 0.57
PE53 Spect 3 (T_BRANCHB1) EU CMRY0102 0.03397076 -19.69487753 0.57 0.57
PE55 Spect 4 (T_BRANCHB2) EU CMRY0103 0.033849823 -20.45497342 0.57 0.56
PE44 Spect 5 (T_ANATRAY1) EU CMRY0104 0.033714199 -21.38677463 0.56 0.56
PE62 Spect 6 (T_ANATRAY2) EU CMRY0105 0.033866794 -20.61866605 0.56 0.55
JF72 EU TEMP EU CMRY0106 0.033746334 -21.23971713 0.57 0.57
YK64 COLD-LOAD1 TEMP SU CMRY0123 0.074412308 -184.5559698 2.23 2.07
YK68 COLD-LOAD2 TEMP SU CMRY0124 0.07487112 -184.189303 2.24 2.06
YG80 WARM-LOAD1 TEMP SU CMRY0125 0.07334614 -184.2668159 2.58 2.38
YK69 WARM-LOAD2 TEMP SU CMRY0136 0.073248693 -184.2651337 2.55 2.36
JF54 O/B TEMP SU CMRY0126 0.0740733 -185.4560633 2.97 2.95
JF73 TELESCOPE-1 TEMP SU CMRY0127 0.0739253 -185.1412464 3.14 3.12
LS46 TELESCOPE-2 TEMP SU CMRY0128 0.073047302 -186.2529661 2.93 2.91
LS54 PLL-TEMP (S/N 02) SU CMRY0129 0.073500419 -187.3020201 2.26 2.24
YK62 IFP-DET-TEMP (smm) (SN02) SU CMRY0130 0.073558985 -186.2027378 2.40 2.39
YK60 IFP-AMP-TEMP (mm) (SN02) SU CMRY0131 0.075016325 -185.4664865 2.44 2.42
LS41 SMM-LO-GUNN TEMP (SN02) SU CMRY0132 0.073749861 -186.9800848 2.33 2.31
HZ55 MM-LO-GUNN TEMP (SN02) SU CMRY0133 0.07461183 -185.4925038 2.88 2.86
JF57 MIRROR MOTOR TEMP SU CMRY0134 0.073966056 -185.5862737 2.96 2.93
JF70 SEN-EL TEMP SU CMRY0135 0.074054605 -185.623042 2.92 2.90
7.1.2.4.2 Voltage Calibration
There are 18 Voltages read out in the housekeeping data. The calibration for all of these is linear as given in the table below.
Description RSDB Name b [V] m*Raw Data Number [V/DN]
+5 EU Voltage CMRY0107 0 1.5647700E-03
+12 EU Voltage CMRY0108 0 3.5557460E-03
-12 EU Voltage CMRY0109 0 -5.7070700E-03
+3.3 EU Voltage CMRY0110 0 9.4854200E-04
+24 EU Voltage CMRY0111 0 1.2184308E-02
+5 Ana EU Voltage CMRY0112 0 1.5863220E-03
USO TLM Heating Voltage CMRY0119 0 1.2210012E-03
USO TLM RF Voltage CMRY0120 0 1.2210012E-03
CTS-Ana-1 Voltage CMRY0121 0 1.5258790E-03
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
Description RSDB Name b [V] m*Raw Data Number [V/DN]
CTS-Ana-2 Voltage CMRY0122 0 1.5258790E-03
+5V SBEU Voltage CMRY0137 0 1.5561130E-03
+12-1 SBEU Voltage CMRY0138 0 3.5520800E-03
+12-2 SBEU Voltage CMRY0139 0 3.5574990E-03
-12 SBEU Voltage CMRY0140 0 -5.8037160E-03
SMM-PLL-ERR Voltage CMRY0147 0 9.3155000E-04
FS1-ERR Voltage CMRY0148 0 1.2207030E-03
FS2-ERR Voltage CMRY0149 0 1.2207030E-03
FS3-ERR Voltage CMRY0150 0 1.2207030E-03
The USO Telemetry Heating Voltage and RF Voltage are not calibrated for temperature and power.
7.1.2.4.3 Current Calibration
There are 12 Currents read out in the housekeeping data. The calibration for all of these is linear as given in the table below.
Description Units RSDB Name b [A or mA] m*Raw Data Number [A or mA/DN]
+5V EU Current A CMRY0113 0 7.6320000E-04
+12V EU Current A CMRY0114 0 2.2749800E-04
-12V EU Current A CMRY0115 0 2.6894900E-05
+24V EU Current A CMRY0116 0 2.1656800E-04
+3.3V EU Current A CMRY0117 0 1.1616000E-03
+5V Ana EU Current A CMRY0118 0 1.3607000E-04
+5V SBEU Current A CMRY0141 0 3.3313900E-04
+12V-1 SBEU Current A CMRY0142 0 2.7165900E-04
+12V-2 SBEU Current A CMRY0143 0 2.1425100E-04
-12V SBEU Current A CMRY0144 0 4.6708500E-05
MM Gunn Current mA CMRY0145 0 1.5258789E-01
SMM-PLL Gunn Current mA CMRY0151 0 6.2948800E-02
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
7.1.2.4.4 Other Calibration
7.1.2.5 Limits
The limits are based on values obtained during thermal vacuum testing at JPL. The general approach was to set the soft limit at least 10% beyond the expected difference between the maximum and minimum expected value and the hard limit at least 20% beyond the expected values.
Telemetry Name RSDB Name Units Condition Hard Low Soft Low Soft High Hard High
Spect_T1 LMR10023 C CTS/Smm Cntm or CTS/Dual Cntm -40.0 -35.0 80.0 85.0
Spect_T2 LMR20023 C CTS/Smm Cntm or CTS/Dual Cntm -40.0 -35.0 80.0 85.0
Spect_T3 LMR30023 C CTS/Smm Cntm or CTS/Dual Cntm -40.0 -35.0 80.0 85.0
Spect_T4 LMR40023 C CTS/Smm Cntm or CTS/Dual Cntm -40.0 -35.0 80.0 85.0
Spect_T5 removed C Fails intermittently at high temperatures
Spect_T6 LMR60023 C CTS/Smm Cntm or CTS/Dual Cntm -40.0 -35.0 80.0 85.0
EU_Temp LMR00021 C TRUE for all modes -30 -20 50 60
ECal_Temp LMR00022 Raw TRUE for all modes 2585 2595 2630 2640
+5V_EU LMR00024 V TRUE for all modes 4.5 4.7 5.3 5.5
+12V_EU LMR00025 V TRUE for all modes 11.0 11.5 13.4 13.5
-12V_EU LMR00026 V TRUE for all modes -13.5 -13.2 -11.5 -11.0
+3.3V_EU LMR00027 V TRUE for all modes 2.9 3.1 3.6 3.7
+24V_EU LMR00029 V TRUE for all modes 22.0 22.5 26.5 27.0
+5V_Ana_EU LMR00028 V TRUE for all modes 4.5 4.7 5.3 5.5
+5V_Curr_EU LMR00030 A TRUE for all modes 0 0.1 3 3.3
+12V_Curr_EU LMR00031 A TRUE for all modes 0 0.01 0.8 0.9
-12V_Curr_EU LMR00032 A TRUE for all modes 0 0.01 0.11 0.113
+24V_Curr_EU LMR00035 A TRUE for all modes 0 0.01 0.8 0.83
+3.3V_Curr_EU LMR00033 A TRUE for all modes 0 0.01 2.0 3.0
+5V_Ana_Curr_EU LMR00034 A TRUE for all modes 0 0.01 0.8 1.0
TLM_Heating LMR00036 V TRUE for all modes 0.003 0.007 1.5 2.2
TLM_RF LMR00037 V TRUE for all modes 0.003 0.006 0.1 0.15
CTS_V_Ana_1 LMR10038 V CTS/Smm Cntm or CTS/Dual Cntm 2.4 2.43 2.6 2.65
CTS_V_Ana_2 LMR20038 V CTS/Smm Cntm or CTS/Dual Cntm 2.4 2.43 2.6 2.65
Cold_Load1_Temp LMR10039 C TRUE for all modes -183.0 -180.0 105.0 107.0
Cold_Load2_Temp LMR20039 C TRUE for all modes -183.0 -180.0 105.0 107.0
Warm_Load1_Temp LMR10040 C TRUE for all modes -30.0 -20.0 75.0 85.0
Warm_Load2_Temp LMR20040 C TRUE for all modes -30.0 -20.0 75.0 85.0
OB_Temp LMR00041 C TRUE for all modes -30.0 -20.0 35.0 40.0
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Telemetry Name RSDB Name Units Condition Hard Low Soft Low Soft High Hard High
PAY412-MIRO Temp 2 A Limits (Rosetta TRP) LMR00074 C MIRO off -30.0 -25.0 55.0 60.0
PAY412-MIRO Temp 2 A Limits (Rosetta TRP) LMR00074 C TRUE for all modes -20.0 -15.0 40.0 45.0
PAY413-MIRO Temp 2 B Limits (Rosetta TRP) LMR00075 C MIRO Off -30.0 -25.0 55.0 60.0
PAY413-MIRO Temp 2 B Limits (Rosetta TRP) LMR00075 C TRUE for all modes -20.0 -15.0 40.0 45.0
PAY414-MIRO Temp 1 A Limits (Rosetta TRP) LMR00076 C MIRO off -30.0 -25.0 55.0 60.0
PAY414-MIRO Temp 1 A Limits (Rosetta TRP) LMR00076 C TRUE for all modes -20.0 -15.0 55.0 65.0
Telescope1_Temp LMR00071 C TRUE for all modes -183.0 -180.0 105.0 107.0
Telescope2_Temp LMR00072 C TRUE for all modes -183.0 -180.0 105.0 107.0
PLL_Temp LMR00042 C TRUE for all modes -30.0 -20.0 70.0 75.0
IFP_DET_Temp LMR00043 C TRUE for all modes -30.0 -20.0 65.0 70.0
IFP_AMP_Temp LMR00044 C TRUE for all modes -30.0 -20.0 65.0 70.0
SMM_LO_GUNN LMR00045 C TRUE for all modes -30.0 -20.0 45.0 50.0
MM_LO_GUNN LMR00046 C TRUE for all modes -30.0 -20.0 45.0 50.0
Motor_Temp LMR00047 C TRUE for all modes -30.0 -20.0 100.0 150.0
Sen_El Temp LMR00048 C TRUE for all modes -30.0 -20.0 65.0 70.0
Cal_Temp_Low LMR00049 Raw TRUE for all modes 430 440 500 560
Cal_Temp_High LMR00050 Raw TRUE for all modes 3650 3700 3850 3900
+5V_SBEU LMR00051 V TRUE for all modes 4.5 4.7 5.3 5.5
+12V_1_SBEU LMR00052 V TRUE for all modes 11.0 11.5 12.6 13.0
+12V_2_SBEU LMR00054 V TRUE for all modes 11.0 11.5 12.5 13.0
-12V_SBEU LMR00053 V TRUE for all modes -13.0 -12.9 -10.8 -10.3
+5V_Curr_SBEU LMR00055 A TRUE for all modes 0.001 0.01 1.5 1.6
+12V_Curr_1_SBEU LMR00056 A TRUE for all modes 0.001 0.01 0.55 0.6
+12V_Curr_2_SBEU LMR00058 A TRUE for all modes 0.001 0.01 0.83 0.89
-12V_Curr_SBEU LMR00057 A TRUE for all modes 0.001 0.01 0.2 0.25
MM_GUNN_Curr LMR00063 mA Mm Cntm, Dual Cntm, CTS/Dual Cntm 140.0 145.0 160.0 170.0
SMM_PLL_ERR LMR00059 V CTS/Smm Cntm or CTS/Dual Cntm 1.0 2.0 2.75 3.3
FS1_ERR LMR00060 V CTS/Smm Cntm or CTS/Dual Cntm 1.0 1.4 3.0 3.5
FS2_ERR LMR00061 V CTS/Smm Cntm or CTS/Dual Cntm 1.0 1.4 3.0 3.5
FS3_ERR LMR00062 V CTS/Smm Cntm or CTS/Dual Cntm 1.0 1.4 3.0 3.5
SMM_PLL_GUNN_Curr LMR00063 mA CTS/Smm Cntm or CTS/Dual Cntm 110.0 115.0 150.0 160.0
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
7.1.2.6 RSDB Entries
Telemetry Packet: YMR00001 - MIRO Housekeeping Parameters: NMRAxxx - identified in table above The telemetry parameters that have subparameters are listed here.
NMRA0002 - Operational Mode
NMRD0201 Power Mode NMRD0202 CTS Integration Period NMRD0203 Continuum Sum Value NMRD0204 CTS Smoothing Value NMRD0205 Reserved (not used) NMRD0206 Reserved (not used) NMRD0207 Reserved
NMRAH141 - MR71/4 PckSeqCount
NMRDH141 Segmentation Flag NMRDH142 MR 71/4 SourceSeqCount
NMRAH143 - MR71/4 DataFieldHdr time
NMRDH143 MIRO 71/4 Coarse time NMRDH144 MIRO 71/4Fine time
NMRAH144 - MR71/4 DataFieldHdr PUS
NMRDH145 PUS version number NMRDH146 Checksum flag NMRDH147 Data field header spare NMRDH148 MIRO 71/4 Packet Type NMRDH149 MIRO 71/4 Packet Subtype NMRDH140 Data field header pad
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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Date: 31 September 2018
7.1.3 SPECTROSCOPIC (CTS) SCIENCE TELEMETRY
7.1.3.1 Description
The submillimeter-wave spectroscopic frequencies allow simultaneous observations of 8 spectral lines; H2O (556.936 GHz), H217O (552.021 GHz), H218O (547.676 GHz), CO (576.268 GHz), NH3 (572.498 GHz), and CH3OH (553.146, 568.566, 579.151 GHz). These lines are returned in 7 down converted bands (defined by filters, see Section 9.3.4), that are spectrally analyzed by the Chirp Transform Spectrometer (CTS).
Band 1 (1270 MHz): H2O 17O
Band 2 (1300 MHz): H2
Band 3 (1320 MHz): CH3OH (579.151 GHz) 18O
Band 4 (1340 MHz): H2Band 5 (1363 MHz): CO Band 6 (1389 MHz): CH3OH (568.566 GHz) Band 7 (1407, 1425 MHz): NH3, CH3OH (553.146 GHz)
Spectroscopic data is generated in three of the MIRO operating modes:
1.
CTS/Submillimeter-wave Continuum mode.
2.
CTS/Dual continuum mode.
3.
Asteroid mode.
Two types of data are returned.
1.
Calibration data
2.
Differenced frequency switched data.
Each digitized spectrum contains 4096, ~44 KHz wide channels (unless CTS smoothing is invoked). Note that the precise channel width is temperature dependent, as discussed in Section 9.4.
In addition to the spectroscopic data, additional related information is packaged in the spectroscopic science file. The first CTS science packet contains the operational mode, the science data type (in this case CTS data), the calibration mirror location, the CTS multiplier value, the calibration indicator, and the LO frequency setting. Last CTS science packet contains PLL alarm data for the CTS scan. One byte of PLL alarm data will be present for each 5-second CTS scan that is contained in the CTS data set.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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7.1.3.2 Packet Definition Spectroscopic (CTS) Science Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Segmentation Flags NMRDH1C1 2 11 EID-A Mandatory
Source Sequence Count NMRDH1C2 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH1C2 16 110110111 or 100110110 This gets set to the size of the source data field (in bytes) + 9. This is 439 bytes except for the last packet of each spectrum, when it is 310 bytes.
Time NMRAH1C3 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH1C5 3 000 EID-A Specified, Science data
Checksum Flag NMRDH1C6 1 0 EID-A Mandatory
Spare NMRDH1C7 4 0000 EID-A Mandatory
Packet Type NMRDH1C8 8 00010100 EID-A Specified, Science Data Transfer = 20
Packet Subtype NMRDH1C9 8 00000011 EID-A Specified, RTU Interface = 3
Pad NMRDH1C0 8 00000000 EID-A Specified
Source Data 3440 430 bytes Detailed definition on following page
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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CTS Science Source Data Definition
Data Element Size (Bits) Value (Binary) Comment
Operational mode 16 MIRO operational mode
Science data type 8 00000001 CTS data = 1
Mirror location 8 1=sky, 2=hot, 3=cold
CTS multiplier value 16 N All CTS data values should be multiplied by 2^N, when a user defined CTS mask is in effect this will be zero.
Data set number 16 1 up counter Specifies CTS data set number
Packet number 8 Specifies packet number within CTS data set
Calibration indicator 4 0=Calibration, 1=nominal CTS data
LO frequency setting 4 0=LO frequency 0, 1= LO frequency 1 Note: This setting only applies to calibration data as indicated by the calibration indicator.
CTS data 3360 Usually 420 bytes, but 270 in the last packet of each spectrum Processed CTS data. Multiple data packets depending on value of CTS Smoothing Value. Note: Last CTS packet contains PLL alarm data for the CTS scan. One byte of PLL alarm data will be present for each 5-second CTS scan that is contained in the CTS data set. The 4 most significant bits of each PLL alarm byte represent the PLL alarm states at 0.05 seconds elapsed time into the scan. The 4 least significant bits indicate whether the corresponding PLL alarm bit ever changed. See details below.
Note: When the asteroid mode bit in the "operational mode" data element is set the following CTS science data packet decoding rules apply: The "calibration indicator" will always be zero even though some of the asteroid data is calibration data and some is not. All asteroid data sets are the same and consist of 4096 32-bit samples packed into 39 TM packets of 420 bytes each, and 1 packet of 4 bytes plus 1 byte of PLL data. The "LO frequency setting" will indicate which LO frequency the data was captured at.
7.1.3.3 Expected Values
Typical spectra are shown below.
CTS calibration Data: Shown above is a typical CTS calibration data. The vertical scale is in counts (about 4 x 107); the top horizontal scale in frequency (MHz), the bottom horizontal scale is in channel numbers. The CTS calibration data shows the structure of the IF band pass. The 7 bands are indicated by the dotted lines. Six of these scans are obtained for each calibration-(1) observing the hot load at -5 MHz, (2) observing the hot load at +5 MHz, (3) observing the cold load at -5 MHz, (4) observing the cold load at +5 MHz, (5) observing the source position at -5 MHz, and (6) observing the source position at +5 MHz. Since the count level is dominated by the receiver noise, these 6 scans look very similar. The spike at 1364.7 MHz is internal to the instrument. Though unintentional, it serves as a good indicator that the CTS pulse position is set correctly.
CTS differenced data is shown above. If there were no drift between the 5-second LO switches the data would be at 0 counts. In this figure it is slightly above 0 consistent with a linear increasing drift. The structure seen in the calibration data has been cancelled out. The seven bands are indicated by the dotted lines. The peak-to-peak signal is consistent with 30-second integration time, 44-kHz bandwidth, and receiver noise temperature of about 5000 K.
PLL ALARM BITS (ADDITIONAL DETAIL)
The PLL alarm bits are comprised of 6 individual bits that are tracked during the CTS scans. The 6 bits are shown in the table below:
Frequency Synthesizer 3 Frequency Synthesizer 2 Frequency Synthesizer 1 SMM Low SMM High LO Frequency
The 3 MSB are the 3 frequency synthesizer alarms. The 3 LSB are the 3 PLL alarms. For the frequency synthesizer alarm bits 1 = locked and 0 = alarm condition. For the PLL alarm bits 0 = locked and 1 = alarm condition. Since the number of bits was increased from 4 in the EQM to 6 in the flight a scheme was developed to consolidate the 6 bits down to 4 to generate the same amount of returned telemetry. The 3 frequency synthesizer bits are ANDed together upon
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
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their initial sampling on continuum sample number 1. If all 3 bits are 1, indicating lock, then the initial value of the consolidated frequency synthesizer bit will be 1. If any of the 3 frequency synthesizer bits are 0 then the consolidated frequency synthesizer bit will be 0. The 3 PLL alarm bits have an initial state that corresponds directly to the 0 or 1 returned from the hardware. The table below shows the 4 bits that comprise the initial alarm bit state as returned in the 4 MSB of the alarm data for each CTS scan:
Consolidated Frequency SMM Low SMM High LO Frequency
Synthesizer Bit
These 4 bits show the initial state of the alarms as sampled during the first continuum sample approximately 50 milliseconds into the CTS scan. There are 99 remaining continuum samples during the 5 second CTS scan. The 4 LSB of the alarm data are used to indicate if the alarm bits ever change from their initial state at any time during the remaining 99 samples. For the 3 PLL bits it is very straightforward. If the initial state ever changes, the "change bit" in the 4 LSB will show a 1. If the PLL alarm never changes then the "change bit" will show a
0. The final returned 8 bits are shown below:
Consolidated Frequency Synthesizer Bit SMM Low SMM High LO Frequency Consolidated Frequency Synthesizer Change Bit SMM Low Change Bit SMM High Change Bit LO Frequency Change Bit
The consolidated frequency synthesizer change bit works as follows. If any of the 3 initial frequency synthesizer bits changes from its initial value during the CTS scan, the change bit will be set to 1. If none of the 3 bits change during the scan then the change bit will be set to 0. The 3 frequency synthesizer bits were consolidated because it was determined that they were likely to be the most stable of the 6 alarm bits. If the 3 frequency synthesizers are working perfectly and never lose lock during a CTS scan then the returned bit pair should be 1-0. Since they are consolidated it will not be possible to determine exactly which one is losing lock should one or more of them lose lock. Since each of the 3 PLL alarm bits is separately tracked it will be possible to determine which of them is losing lock during each scan.
7.1.3.4 Calibration
The absolute calibration of the instrument is obtained by observing two blackbody loads at two different temperatures. The cold load is exposed to space, while the hot target is located inside the spacecraft and can be heated. Calibration occurs automatically about every 30 minutes.
For spectroscopic observations, the submillimeter-wave receiver is operated in a "frequency switched" mode to eliminate residual baseline ripple. For half the integration time, the signal frequency is shifted 5 MHz above the nominal frequency, while the other half of the time it is shifted to 5 MHz below. The
frequency switching occurs every 5 seconds. The +5MHz data (referred to as LO1) are subtracted from the -5 MHz (LO0) data by the on-board computer.
The calibration data is not differenced. It consists of 6 scans each with 30 seconds integration time.
1. Hot load with LO switched to -5MHz
2. Hot Load with the LO switched to +5MHz
3. Cold load with the LO switched to -5Mhz
4. Cold Load with the LO switched to +5MHz
5. Source with the LO switched to -5 MHz
6. Source with the LO switched to +5 MHz
7.1.3.5 RSDB Entries
The Spectroscopic data file YMR00011. Some of the header values are called specifically with NMR ... designations. These are indicated in the above tables.
7.1.4 SUBMILLIMETER CONTINUUM SCIENCE TELEMETRY
7.1.4.1 Description
The submillimeter-wave receiver provides continuum data as well as spectroscopic data. The submillimeter-wave continuum band is 1 GHz wide centered at 569.813 GHz (USB) and 555.813 GHz (LSB), since the receiver is double sideband.
Submillimeter-wave continuum data is taken in 5 MIRO operating modes.
1.
Submillimeter continuum mode.
2.
Dual continuum mode.
3.
CTS/Submillimeter continuum mode.
4.
CTS/Dual continuum mode.
5.
Asteroid mode.
A continuous digitized stream of data is returned. The integration time per data point defaults to 50. It is controlled by the continuum summing parameter in the Change Mode telecommand. The data output will be summed over 50 ms (1 continuum value summed), 100 ms (2 continuum values summed), 250 ms (5 continuum values summed), 500 ms (10 continuum values summed) or 1000 ms (20 continuum values summed). A fixed value may be subtracted from these measurements depending on whether or not the Continuum Subtraction Value telecommand has been executed. The subtraction value is contained in the miscellaneous science file. When the summing value is set to either 1 or 2, additional timestamps are placed in the continuum packet.
In addition to the spectroscopic data, additional related information is packaged in the spectroscopic science file. The first CTS science packet contains the operational mode, the science data type (in this case submillimeter-wave
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continuum data), the calibration mirror location, MM subtraction value, SMM subtraction value, the calibration indicator, and the LO frequency setting. In addition time tags are applied approximately every 5 seconds. If in a spectroscopic mode is on, then the level is changed by LO frequency switching.
7.1.4.2 Packet Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Segmentation Flags NMRDH1C1 2 11 EID-A Mandatory
Source Sequence Count NMRDH1C2 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH1C2 16 Varies This gets set to the size of the source data field (in bytes) + 9. This is nominally 439 bytes, but can be as small as 49 depending on the number of samples contained in the packet.
Time NMRAH1C3 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH1C5 3 000 EID-A Specified, Science data
Checksum Flag NMRDH1C6 1 0 EID-A Mandatory
Spare NMRDH1C7 4 0000 EID-A Mandatory
Packet Type NMRDH1C8 8 00010100 EID-A Specified, Science Data Transfer = 20
Packet Subtype NMRDH1C9 8 00000011 EID-A Specified, RTU Interface = 3
Pad NMRDH1C0 8 00000000 EID-A Specified
Source Data Varies 40-430 bytes Detailed definition on following page
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Continuum (Submillimeter) Source Data Definition
Data Element Size (bits) Value (binary) Comment
Operational mode 16 MIRO Operational mode
Science data type 8 00000010 Submillimeter data = 2
Mirror location 8 1=sky, 2=hot, 3=cold
Calibration indicator 16 0=Calibration, 1=nominal CTS data
MM subtraction value 16 Current value as uplinked via TC
SMM subtraction value 16 Current value as uplinked via TC
Reserved 16 0000000000000000
Timestamp 2 48 Time of 101st continuum sample if continuum summing value is 1. Time of 51st continuum sample if continuum summing value is 2. Zero otherwise.
Timestamp 3 48 Time of 101st continuum sample if continuum summing value is 2. Zero otherwise.
Timestamp 4 48 Time of 151st continuum sample if continuum summing value is 2. Zero otherwise
Continuum Data Varies 10-400 bytes Field is nominally 400 bytes, but can be as short as 10 bytes if flushed for a mode change. Alternating sets of continuum data at LO1 and LO2 if CTS running. Size of each set depends on continuum summing value.
7.1.4.3 Expected Value
Typical submillimeter continuum data are shown below. The first scan shown below is typical of a non-spectroscopic mode-either submillimeter-continuum mode or dual continuum mode. The vertical axis in the plot above is counts. The horizontal scale is time, in this case in minutes. In addition to the source date (about 7880 counts), the effect of a calibration sequence is seen as well. The higher level (about 7900 counts) results from observing the hot load for 30 seconds, while the lower level (about 7780 counts) results from observing the cold load for 30 seconds.
The second scan below shows typical submillimeter continuum data in a spectroscopic mode-either CTS/submillimeter continuum mode or CTS/dual continuum mode. The effect of the +/-5MHz frequency switching every 5 seconds is clearly seen by a slight change in level. To process this data, it is necessary to bin it into the appropriate frequency switch before applying the calibration.
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7.1.4.4 Calibration
The absolute calibration of the instrument is obtained by observing two blackbody loads at two different temperatures. The cold load is exposed to space, while the hot target is located inside the spacecraft and can be heated. Calibration occurs automatically about every 30 minutes.
7.1.4.5 RSDB Entries
The Spectroscopic data file YMR00011. Some of the header values are called specifically with NMR ... designations. These are indicated in the above tables.
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7.1.5 MILLIMETER CONTINUUM SCIENCE TELEMETRY
7.1.5.1 Description
The millimeter-wave receiver provides continuum data. The millimeter-wave continuum band is 500 MHz wide centered at about 188.75 GHz (LSB) and
191.25 GHz (USB), since the receiver is double sideband. Note that the LO is not locked so that these are as uncertain as the LO frequency.
Millimeter-wave continuum data is taken in 4 MIRO operating modes.
1.
Millimeter continuum mode.
2.
Dual continuum mode.
3.
CTS/Dual continuum mode.
4.
Asteroid mode.
A continuous digitized stream of data is returned. The integration time per data point defaults to 50. It is controlled by the continuum summing parameter in the Change Mode telecommand. The data output will be summed over 50 ms (1 continuum value summed), 100 ms (2 continuum values summed), 250 ms (5 continuum values summed), 500 ms (10 continuum values summed) or 1000 ms (20 continuum values summed). A fixed value may be subtracted from these measurements depending on whether or not the Continuum Subtraction Value telecommand has been executed. The subtraction value is contained in the Miscellaneous Science file. When the summing value is set to either 1 or 2, additional timestamps are placed in the continuum packet.
7.1.5.2 Packet Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Segmentation Flags NMRDH1C1 2 11 EID-A Mandatory
Source Sequence Count NMRDH1C2 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH1C2 16 Varies This gets set to the size of the source data field (in bytes) + 9. This is nominally 439 bytes, but can be as small as 49 depending on the number of samples contained in the packet.
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Data Element RSDB Name Size (bits) Value (binary) Comment
Time NMRAH1C3 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH1C5 3 000 EID-A Specified, Science data
Checksum Flag NMRDH1C6 1 0 EID-A Mandatory
Spare NMRDH1C7 4 0000 EID-A Mandatory
Packet Type NMRDH1C8 8 00010100 EID-A Specified, Science Data Transfer = 20
Packet Subtype NMRDH1C9 8 00000011 EID-A Specified, RTU Interface = 3
Pad NMRDH1C0 8 00000000 EID-A Specified
Source Data Varies 40-430 bytes Detailed definition on following page
Continuum (Millimeter) Source Data Definition
Data Element Size (bits) Value (binary) Comment
Operational mode 16 MIRO Operational mode
Science data type 8 00000011 Millimeter data = 3
Mirror location 8 1=sky, 2=hot, 3=cold
Calibration indicator 16 0=Calibration, 1=nominal CTS data
MM subtraction value 16 Current value as uplinked via TC
SMM subtraction value 16 Current value as uplinked via TC
Reserved 16 0000000000000000
Timestamp 2 48 Time of 101st continuum sample if continuum summing value is 1. Time of 51st continuum sample if continuum summing value is 2. Zero otherwise.
Timestamp 3 48 Time of 101st continuum sample if continuum summing value is 2. Zero otherwise.
Timestamp 4 48 Time of 151st continuum sample if continuum summing value is 2. Zero otherwise
Continuum Data Varies 10-400 bytes Field is nominally 400 bytes, but can be as short as 10 bytes if flushed for a mode change. Alternating sets of continuum data at LO 1 and LO 2 if CTS running. Size of each set depends on continuum summing value.
7.1.5.3 Expected Values
Typical millimeter-wave continuum data is shown below. The vertical axis in the plot above is counts. The horizontal scale is time, in this case in minutes. In addition to the source date (about 7335 counts), the effect of a calibration sequence is seen as well. The higher level (about 7400 counts) results from observing the hot load for 30 seconds, while the lower level (about 7000 counts) results from observing the cold load for 30 seconds.
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7.1.5.4 Calibration
The absolute calibration of the instrument is obtained by observing two blackbody loads at two different temperatures. The cold load is exposed to space, while the hot target is located inside the spacecraft and can be heated. Calibration occurs automatically about every 30 minutes.
7.1.5.5 RSDB Entries
The Spectroscopic data file YMR00011. Some of the header values are called specifically with NMR ... designations. These are indicated in the above tables.
7.1.6 MISCELLANEOUS SCIENCE TELEMETRY
7.1.6.1 Description
The miscellaneous science telemetry contains parameters critical to analyzing the data that are not captured in the other science files.
A Miscellaneous Science file is generated under the following circumstances:
1.
Whenever a mode change takes place. This happens not only on a Mode Change command, but also automatically with the following telecommands: CTS Internal Cal, IFP Power Control and Asteroid Mode.
2.
During autonomously executed calibration sequences that take place roughly every 30 minutes following a Mode Change telecommand.
3.
When the CTS Data Mask telecommand is executed.
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4. When a CTS internal table calibration takes place. (Per this and item 1, the CTS Internal Cal telecommand generates two MS packets, while the Asteroid mode command, which has two mode changes and a cal, generates three.)
7.1.6.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1100 EID-A Specified, Private (science) = 12
Segmentation Flags NMRDH1C1 2 11 EID-A Mandatory
Source Sequence Count NMRDH1C2 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH1C2 16 110110111 This gets set to the size of the source data field (in bytes) + 9. This is 439 bytes.
Time NMRAH1C3 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH1C5 3 000 EID-A Specified, Science data
Checksum Flag NMRDH1C6 1 0 EID-A Mandatory
Spare NMRDH1C7 4 0000 EID-A Mandatory
Packet Type NMRDH1C8 8 00010100 EID-A Specified, Science Data Transfer = 20
Packet Subtype NMRDH1C9 8 00000011 EID-A Specified, RTU Interface = 3
Pad NMRDH1C0 8 00000000 EID-A Specified
Source Data 3440 430 bytes Detailed definition on following page
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Miscellaneous Science Source Data Definition
Data Element Size (bits) Value (binary) Comment
Operational mode 16 MIRO operational mode
Science data type 8 00000100 Miscellaneous science data = 4
Mirror location 8 1=sky, 2=hot, 3=cold
Reserved 48 Header reserved area
Asteroid Mode Programmed 16 0 or 1 0=Asteroid mode not currently programmed, 1=Asteroid mode programmed
Asteroid Mode Start Time 32 Varies Spacecraft time for asteroid mode execution to start
Millimeter Subtraction Value 16 Varies Unsigned integer subtracted from each submillimeter sample. As specified in the TC parameter.
Submillimeter Subtraction Value 16 Varies Unsigned integer subtracted from each millimeter sample. As specified in the TC parameter.
CTS Run Time 40 Varies ASCII representation of floating point: i.e., 4.878
Continuum / CTS Unloading Gap 40 Varies ASCII representation of floating point value: i.e., 0.056
CTS Table 1 Midpoint #1 48 Varies ASCII representation of floating point value: i.e., 125.07
CTS Table 1 Midpoint #2 48 Varies ASCII representation of floating point value: i.e., 125.08
CTS Table 2 Midpoint #1 48 Varies ASCII representation of floating point value: i.e., 125.09
CTS Table 2 Midpoint #2 48 Varies ASCII representation of floating point value: i.e., 125.10
CTS Table 3 Midpoint #1 48 Varies ASCII representation of floating point value: i.e., 125.11
CTS Table 3 Midpoint #2 48 Varies ASCII representation of floating point value: i.e., 125.12
CTS Table 4 Midpoint #1 48 Varies ASCII representation of floating point value: i.e., 125.13
CTS Table 4 Midpoint #2 48 Varies ASCII representation of floating point value: i.e., 125.14
CTS Calibration band #1 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #2 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #3 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #4 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #5 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #6 MSB 8 Varies Valid setting is in the range of 11-31
CTS Calibration band #7 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #1 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #2 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #3 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #4 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #5 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #6 MSB 8 Varies Valid setting is in the range of 11-31
CTS Nominal band #7 MSB 8 Varies Valid setting is in the range of 11-31
PLL Lock Successful Counter 32 Varies The number of times that all 6 PLL lock indicator bits were found to be in lock when a CTS scan was about to be started.
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Data Element Size (bits) Value (binary) Comment
PLL Lock Unsuccessful Counter 32 Varies The number of times that one or more of the 6 PLL lock indicator bits were found to not be in lock when a CTS scan was about to be started.
Reserved 2640 330 bytes Will use as required
7.1.6.3 Expected Value
Two samples of Miscellaneous Science files are given below.
*** Record #27 time = 1171396.767 OpMode = x2000 MirPos = 1AstMode = 0 Ast.Start = 0.000 MM Subtract = 0 SMM Subtract = 0 CTS RunTime = 4.956 Unload Gap = 10.00CTS Midpoints:
126.6 123.5 126.2 127.6 124.4 123.9 125.6 126.1 CTS Cal.band MSBs: 0 0 0 0 0 0 0 CTS Nom.band MSBs: 11 11 11 11 11 11 11 PLL Lock: Success = 2694 Unsuccessful = 268
*** Record #28 time = 1171452.417 OpMode = x2000 MirPos = 3AstMode = 0 Ast.Start = 0.000 MM Subtract = 0 SMM Subtract = 0 CTS RunTime = 4.956 Unload Gap = 0.105CTS Midpoints:
126.6 123.5 126.2 127.6 124.4 123.9 125.6 126.1 CTS Cal.band MSBs: 29 25 25 25 25 25 25 CTS Nom.band MSBs: 21 17 17 17 17 17 17 PLL Lock: Success = 2704 Unsuccessful = 268
7.1.6.4 RSDB Entries
The Spectroscopic data file YMR00011. Some of the header values are called specifically with NMR ... designations. These are indicated in the above tables.
7.1.7 MEMORY DUMP TELEMETRY
7.1.7.1 Description
On receipt of a dump request, the defined area of memory is formatted as a dump telemetry report and transferred to the spacecraft.
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7.1.7.2 Packet Definition Memory Dump Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 1001 EID-A Specified, Private (dump) = 9
Sequence Flags NMRDH191 2 11 EID-A Mandatory
Sequence Count NMRDH192 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length NMRAH192 16 Varies This gets set to the size of the source data field (in bytes) + 9.
Time NMRAH193 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH195 3 010 EID-A Specified
Checksum Flag NMRDH196 1 0 EID-A Mandatory
Spare NMRDH197 4 0000 EID-A Mandatory
Packet Type NMRDH198 8 00000110 EID-A Specified, Memory Management = 6
Packet Subtype NMRDH199 8 00000110 EID-A Specified, 6 = Memory Dump
Pad NMRDH190 8 Variable Copied from TC.
Source Data Varies Variable Detailed definition on following page
Memory Dump Telemetry Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Memory ID NMRDST50 8 01100100 100 = MIROs assigned ID
Number of blocks NMRDST55 8 00000001 Must be 1.
Start address NMRAST51 32 Variable Copied from TC.
Block Length NMRAST52 16 Variable Copied from TC.
Data Block NMRAST53 Varies Variable Contents of dump as requested in the memory dump TC.
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7.1.7.3 Expected Value
Contains the contents of the memory block being dumped, contiguously from the defined address. The block consists of a structured array of memory words, as shown below, repeated a "block_length" number of times.
For 16 bit word memory width:
Data word
2 octets
Unsigned integer
For 32 bit memory width:
Most significant word Least significant word
2 octets 2 octets
7.1.7.4 RSDB Entries
Telemetry Packet: YMR00007 - Memory Dump MID 100 Telemetry Parameters: In table above Telemetry Parameters with subparameters are given below.
NMRAH191 - MR71/9 PckSeqCount
NMRDH191 Segmentation Flag NMRDH192 MR71/9 SourceSeqCount
NMRAH 193 - MR71/9 DataFieldHdr time
NMRDH193 MIRO 71/9 Coarse time NMRDH194 MIRO 71/9Fine time
NMRAH194 - MR71/9 DataFieldHdr PUS
NMRDH195 PUS version number NMRDH196 Checksum flag NMRDH197 Data field header spare NMRDH198 MIRO 71/9 Packet Type NMRDH199 MR 71/9 Packet Subtype NMRDH190 Data field header pad
NMRAST50 - Memory ID Blocks
NMRDST50 Memory ID NMRDST55 Memory Blocks
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7.1.8 MEMORY CHECKSUM TELEMETRY
7.1.8.1 Description
On receipt of a checksum request, the checksum of the contents of the defined area of memory is calculated.
7.1.8.2 Packet Definition Memory Checksum Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 0111 EID-A Specified, Private (event) = 7
Sequence Flags NMRDH171 2 11 EID-A Mandatory
Sequence Count NMRDH172 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length NMRAH172 16 0000000000010011 This gets set to the size of the source data field (in bytes) + 9. In this case, 19.
Time NMRAH173 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH175 3 010 EID-A Specified
Checksum Flag NMRDH176 1 0 EID-A Mandatory
Spare NMRDH177 4 0000 EID-A Mandatory
Packet Type NMRDH178 8 00000110 EID-A Specified, Memory Management = 6
Packet Subtype NMRDH179 8 00001010 EID-A Specified, 10 = Memory Check Report
Pad NMRDH170 8 Variable Copied from TC.
Source Data 80 Variable Detailed definition on following page
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Memory Checksum Telemetry Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Memory ID NMRAST50 8 01100100 100 = MIRO's assigned ID
Number of blocks NMRAST50 8 00000001 Must be 1.
Start address NMRAST51 32 Variable Copied from TC.
Block Length NMRAST52 16 Variable Copied from TC.
Checksum NMRAST54 16 Variable Checksum computed by ESA standard checksum algorithm.
7.1.8.3 Expected Value
Typical output file is shown below.
Time (Pkt Typ, STyp) Data
1143409.69735 ( 6,10) 6401 ff800000 8000 de39 0000
MIRO makes use of a standard ESA CRC computation algorithm/routine. This routine is used to compute the CRCs on incoming telecommand packets and also for computation of the memory checksum that takes place as part of the memory check service. The memory check can be performed on both the RAM and EEPROM areas of memory. The code is as follows:
UINT16 calccrc_( UINT8 *buffer, unsigned count ){UINT16 crc = 0xffff;unsigned i;unsigned j;UINT16 wtemp;char audit_string[80];
for( i = 0; i < count; i++ ){wtemp = buffer[i] << 8;for( j = 0; j < 8; j++ ){if( (crc ^ wtemp) & 0x8000 )crc = (crc << 1) ^ 0x1021;else crc = (crc << 1);wtemp = (wtemp << 1);}}return( crc );
}
When the code is executing and performing a checksum on regular memory (RAM) it proceeds through a byte at a time and the checksum is valid because the RAM is byte addressable. The EEPROM on the other hand is quadword addressable rather than byte addressable.
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The calccrc routine accesses memory one byte at a time, as each byte is then processed individually within the routine. Accessing EEPROM memory via byte accesses produces incorrect data 50% of the time. The following example illustrates the problem. Suppose the first quadword of EEPROM located at 0xFF800000 contained the value 0xAABBCCDD. If one were to read the following memory locations via byte accesses to locations 0xFF800000, 0xFF800001, 0xFF800002 and 0xFF800003 one would get 0xAA, 0xAA, 0xDD and 0xDD respectively. Craig Hatfield obtained these results by running code on a flight rad6000.
7.1.8.4 RSDB Entries
Telemetry Packet: YMR00008 - Memory Check MID 100 Telemetry Parameters: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.9 MIRO ON (PROGRESS EVENT REPORT #1) TELEMETRY
7.1.9.1 Description
The MIRO On progress event report is generated when the MIRO flight software has come up normally and received a time synchronization TC packet and the associated TSY pulse from the spacecraft.
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7.1.9.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Normal/Progress Report = 1
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
MIRO On (Progress Event Report #1) Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111110 MIRO range given in EID-A 2.8. This one is 43006. This is generated when the flight software has come up normally and received a time synchronization TC packet and the associated TSY pulse from the spacecraft. Basically when we synch to spacecraft time for the first time.
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7.1.9.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5, 1) a7fe 0000 (note that a7fe(HEX) = 43006(DEC))
7.1.9.4 RSDB Entries
Telemetry Packet: YMR00012 - Progress Event 1 Telemetry Parameter: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.10 ASTEROID MODE STARTED (PROGRESS EVENT REPORT #2) TELEMETRY
7.1.10.1 Description
This asteroid mode started report is generated when the flight software begins running the asteroid mode sequence. This should correlate to the asteroid mode start time issued in the asteroid mode TC.
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7.1.10.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Normal/Progress Report = 1
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
Asteroid Mode Started (Progress Event Report #2) Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111111 MIRO range given in EID-A 2.8. This one is 43007. This is generated when the flight software begins running the asteroid mode sequence. This should correlate to the asteroid mode start time issued in the asteroid mode TC.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.10.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5, 1) a7ff 0000 (note that a7ff(HEX) =43007(DEC))
7.1.10.4 RSDB Entries
Telemetry Packet: YMR00013 - Progress Event 2 Telemetry Parameter: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.11 ASTEROID MODE COMPLETED (PROGRESS EVENT REPORT #3) TELEMETRY
7.1.11.1 Description
This asteroid mode completed report is generated when the flight software completes the asteroid mode sequence.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.11.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Normal/Progress Report = 1
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
Asteroid Mode Completed (Progress Event Report #3) Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010100000000000 MIRO range given in EID-A 2.8. This one is 43008. This is generated when the flight software completes the asteroid mode sequence.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.11.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5, 1) a800 0000 (note that a800(HEX) = 43008(DEC))
7.1.11.4 RSDB Entries
Telemetry Packet: YMR00014 - Progress Event 3 Telemetry parameters: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.12 CONNECTION REPORT TELEMETRY
7.1.12.1 Description
Upon receipt of a connection test request, the connection test report is generated if the following was completed successfully after start-up.
1.
Mirror driven to mechanical stop.
2.
Mirror moved successfully to space position.
3.
Time synch received or 60 seconds pass, whichever is first.
4.
MIRO turned on housekeeping telemetry collection.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.12.2 Telemetry Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 0111 EID-A Specified, Private (event) = 7
Sequence Flags NMRDH171 2 11 EID-A Mandatory
Sequence Count NMRDH172 14 000 + 1 up counter First 3 bits are zero indicating "Ground" as the source. The remaining 11 bits are zero initially, and constitute a one-up Telecommand counter. A separate counter is used for each APID/Packet Category combination.
Packet Length NMRAH172 16 0000000000010011 This gets set to the size of the source data field (in bytes) + 9. In this case, 19.
Time NMRAH173 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH175 3 010 EID-A Specified
Checksum Flag NMRDH176 1 0 EID-A Mandatory
Spare NMRDH177 4 0000 EID-A Mandatory
Packet Type NMRDH178 8 00000110 EID-A Specified, Connection Test Report=17
Packet Subtype NMRDH179 8 00001010 EID-A Specified, 2 = Connection Test Report
Pad NMRDH170 8 Variable Copied from TC.
Source Data Variable 0000 0000
7.1.12.3 Expected Value
The expected output for this report is below
Time (Pkt Typ, STyp) Data1139983.43179 (17, 2) 0000 0000
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.12.4 RSDB Entries
Telemetry Packet: YMR00009 - Connection Report
Telemetry Parameters are given in the table above
Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.13 MIRROR ERROR REPORT TYPE 1 TELEMETRY
7.1.13.1 Description
This mirror error report is generated when the mirror fails to achieve the desired position, but then is successfully driven back and then positioned at the space position.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.13.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags NMRDH171 2 11 EID-A Mandatory
Source Sequence Count NMRDH172 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH172 16 0000000000001101 This gets set to the size of the source data field (in bytes) + 9. This is 13 bytes.
Time NMRAH173 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH175 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH176 1 0 EID-A Mandatory
Spare NMRDH177 4 0000 EID-A Mandatory
Packet Type NMRDH178 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH179 8 00000010 EID-A Specified, Warning = 2
Pad NMRDH170 8 00000000 EID-A Specified
Source Data 32 4 bytes Detailed definition on following page
Mirror Error Type #1 Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111001 MIRO range given in EID-A 2.8. This one is 43001. This is generated when the mirror fails to achieve the desired position, but then is successfully driven back then positioned at space.
Failed Position NMRA0063 16 1, 2 or 3 The position that the mirror could not achieve. 1=space, 2=hot, 3=cold
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.13.3 Expected Values
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,2 ) a7f9 0000 (note that a7f9(HEX) = 43001(DEC))0000 0001
7.1.13.4 RSDB Entries
Telemetry Packet: YMR00002 - Mirror Error Type 1 Telemetry Parameter: Identified in table above. Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.14 MIRROR ERROR REPORT TYPE 2 TELEMETRY
7.1.14.1 Description
This mirror error report is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.14.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags NMRDH171 2 11 EID-A Mandatory
Source Sequence Count NMRDH172 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH172 16 0000000000001101 This gets set to the size of the source data field (in bytes) + 9. This is 13 bytes.
Time NMRAH173 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH175 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH176 1 0 EID-A Mandatory
Spare NMRDH177 4 0000 EID-A Mandatory
Packet Type NMRDH178 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH179 8 00000010 EID-A Specified, Warning = 2
Pad NMRDH170 8 00000000 EID-A Specified
Source Data 32 4 bytes Detailed definition on following page
Mirror Error Type #2 Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111010 MIRO range given in EID-A 2.8. This one is 43002. This is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position.
Failed Position NMRA0063 16 1, 2 or 3 The position that the mirror could not achieve. 1=space, 2=hot, 3=cold
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.14.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,2 ) a7fa 0000 (note that a7fa(HEX) = 43002(DEC))0000 0001
7.1.14.4 RSDB Entries
Telemetry Packet: YMR00003 - Mirror Type 2 Telemetry Parameters: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.15 MIRROR ERROR REPORT TYPE 3 TELEMETRY
7.1.15.1 Description
This mirror error report is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position, the pin puller is activated and the space position located.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.15.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000010 EID-A Specified, Warning = 2
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
Mirror Error Type #3 Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111011 MIRO range given in EID-A 2.8. This one is 43003. This is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position, the pin puller is activated and the space position located.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.15.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,2 ) a7fb 0000 (note that a7fb(HEX) = 43003(DEC))
7.1.15.4 RSDB Entries
Telemetry Packet: YMR00004 - Mirror Error Type 3 Telemetry Parameter: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.16 MIRROR ERROR REPORT TYPE 4 TELEMETRY
7.1.16.1 Description
This mirror error command is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position, the pin puller is activated and the space position is not located.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.16.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Ground Action = 3
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
Mirror Error Type #4 Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111100 MIRO range given in EID-A 2.8. This one is 43004. This is generated when the mirror fails to achieve the desired position, is then driven back and then fails to find the space position, the pin puller is activated and the space position is not located.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.16.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,3 ) a7fc 0000 (note that a7fc(HEX) = 43004(DEC))
7.1.16.4 RSDB Entries
Telemetry Packet: YMR00005 - Mirror Error Type 4 Telemetry Parameters are given in the tables above. Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.17 MIRROR ERROR REPORT TYPE 5 TELEMETRY
7.1.17.1 Description
This mirror error report is generated when a previous mirror failure was recovered from and was followed by a subsequent failure.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.17.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001101 This gets set to the size of the source data field (in bytes) + 9. This is 13 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Ground Action = 3
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 32 4 bytes Detailed definition on following page
Mirror Error Type #5 Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010011111111101 MIRO range given in EID-A 2.8. This one is 43005. This is generated when a previous mirror failure was recovered from and was followed by a subsequent failure.
Failed Position NMRA0063 16 1, 2 or 3 The position that the mirror could not achieve. 1=space, 2=hot, 3=cold
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.17.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,3 ) a7fd 0000 (note that a7fd(HEX) = 43005(DEC))0000 0001
7.1.17.4 RSDB Entries
Telemetry Packet: YMR00006 - Mirror Error Type 5 Telemetry Parameters: In table above Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.18 CTS ERROR REPORT TELEMETRY
7.1.18.1 Description
This CTS error report is generated when the CTS busy line is still high when it should already have gone low indicating a scan completion.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.18.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 000 EID-A Mandatory
Type 1 0 EID-A Mandatory
Data Field Header Flag 1 1 EID-A Mandatory
Application Process ID 7 1000111 EID-A Specified, 71
Packet Category 4 111 EID-A Specified, Event = 7
Segmentation Flags 2 11 EID-A Mandatory
Source Sequence Count NMRDH171 14 1 up counter Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRDH172 16 0000000000001011 This gets set to the size of the source data field (in bytes) + 9. This is 11 bytes.
Time NMRAH172 48 Varies Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRAH173 3 010 EID-A Specified, Non-Science data
Checksum Flag NMRDH175 1 0 EID-A Mandatory
Spare NMRDH176 4 0000 EID-A Mandatory
Packet Type NMRDH177 8 00000101 EID-A Specified, Event = 5
Packet Subtype NMRDH178 8 00000011 EID-A Specified, Ground Action = 3
Pad NMRDH179 8 00000000 EID-A Specified
Source Data NMRDH170 16 2 bytes Detailed definition on following page
CTS Error Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Event ID (EID) NMRA0EID 16 1010100000000001 MIRO range given in EID-A 2.8. This one is 43009. This is generated when the CTS busy line is still high when it should already have gone low indicating a scan completion.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.18.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data
1139979.86552 ( 5,3 ) a801 0000 (note that a801(HEX) = 43009(DEC))
7.1.18.4 RSDB Entries
Telemetry Packet: YMR00015 - CTS Error Telemetry Parameters: In table above. Telemetry Parameters with subparts are given below
NMRAH171 - MR71/7 PcktSeqCount
NMRDH171 Segmentation Flag NMRDH172 MR 71/7 SourceSeqCount
NMRAH173 - MR71/7 DataFieldHdr time
NMRDH173 MIRO 71/7 Coarse time NMRDH174 MIRO 71/7Fine time
NMRAH174 - MR71/7 DataFieldHdr PUS
NMRDH175 PUS version number NMRDH176 Checksum flag NMRDH177 Data field header spare NMRDH178 MIRO 71/7 Packet Type NMRDH179 MIRO 71/7 Packet Subtype NMRDH170 Data field header pad
7.1.19 ACCEPT SUCCESS EVENT REPORT TELEMETRY
7.1.19.1 Description
This report is generated when within 4 seconds of successful receipt of a telecommand.
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.19.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 EID-A Mandatory
Type 1 EID-A Mandatory
Data Field Header Flag 1 EID-A Mandatory
Application Process ID 7 EID-A Specified, 71
Packet Category 4 EID-A Specified, Event = 1
Segmentation Flags NMRDH111 2 EID-A Mandatory
Source Sequence Count NMRDH112 14 Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH112 16
Time NMRAH113 48 Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH115 3 EID-A Specified, Non-Science data
Checksum Flag NMRDH116 1 EID-A Mandatory
Spare NMRDH117 4 EID-A Mandatory
Packet Type NMRDH118 8 EID-A Specified, Telecommand Verification = 1
Packet Subtype NMRDH119 8 EID-A Specified, Acceptance Success Report = 1
Pad NMRDH110 8 EID-A Specified
Source Data 32 Detailed definition on following page
Accept Success Event Report Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Global PID NMRAST01 16
Sequence Control NMRAST02 16
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.19.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data1139979.86552 ( 1,1 ) 0000 0000
7.1.19.4 RSDB Entries
Telemetry Packet: YMRST001 - Accept Success Telemetry Parameters: In table above. Telemetry Parameters that have subparameters are listed below.
NMRAH111 - PckSeqCount
NMRDH111 Segmentation Flag NMRDH112 MR 71/1 SourceSeqCount
NMRAH113 - DataFieldHdr PUS
NMRDH113 MIRO 71/1 Coarse time NMRDH114 MIRO 71/1Fine time
NMRAH114 - MR71/1 DataFieldHdr PUS
NMRDH110 Data field header pad NMRDH115 PUS version number NMRDH116 Checksum flag NMRDH117 Data field header spare NMRDH118 MIRO 71/1 Packet Type NMRDH119 MIRO 71/1 Packet Subtype
NMRAST01 - Global PID
NMRDST01 PID NMRDST02 PctCategory
NMRAST02 - Sequence Counts
NMRDST03 Source NMRDST04 Counter
7.1.20 INCOMPLETE PACKET EVENT REPORT TELEMETRY
7.1.20.1 Description
This report is generated when failed to receive whole packet within time out period (2 seconds for OBDH bus).
Reference: RO-MIR-PR-0030 Issue: 7 Rev: 0
ROSETTA
Date: 31 September 2018
7.1.20.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 EID-A Mandatory
Type 1 EID-A Mandatory
Data Field Header Flag 1 EID-A Mandatory
Application Process ID 7 EID-A Specified, 71
Packet Category 4 EID-A Specified, Event = 1
Segmentation Flags NMRDH111 2 EID-A Mandatory
Source Sequence Count NMRDH112 14 Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH112 16
Time NMRAH113 48 Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH115 3 EID-A Specified, Non-Science data
Checksum Flag NMRDH116 1 EID-A Mandatory
Spare NMRDH117 4 EID-A Mandatory
Packet Type NMRDH118 8 EID-A Specified, Telecommand Verification = 1
Packet Subtype NMRDH119 8 EID-A Specified, Acceptance Failure = 2
Pad NMRDH110 8 EID-A Specified
Source Data 16 Detailed definition on following page
Incomplete Packet Event Report Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Global PID NMRAST01 16
Sequence Control NMRAST02 16
Failure Code NMRAST03 16 1
Packet Service Info NMRAST04 16
Length in TC Header NMRAST10 16
Number of Received Bytes NMRAST11 16
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7.1.20.3 Expected values
A typical output is shown below.
Time (Pkt Typ, STyp) Data1139979.86552 ( 1,2 ) 0000 0001
7.1.20.4 RSDB Entries
Telemetry Packet: YMRST002 - Incomplete Packet Telemetry Parameters: In table above. Telemetry Parameters that have subparameters are listed below.
NMRAH111 - PckSeqCount
NMRDH111 Segmentation Flag NMRDH112 MR 71/1 SourceSeqCount
NMRAH113 - DataFieldHdr PUS
NMRDH113 MIRO 71/1 Coarse time NMRDH114 MIRO 71/1Fine time
NMRAH114 - MR71/1 DataFieldHdr PUS
NMRDH110 Data field header pad NMRDH115 PUS version number NMRDH116 Checksum flag NMRDH117 Data field header spare NMRDH118 MIRO 71/1 Packet Type NMRDH119 MIRO 71/1 Packet Subtype
NMRAST01 - Global PID
NMRDST01 PID NMRDST02 PctCategory
NMRAST02 - Sequence Counts
NMRDST03 Source NMRDST04 Counter
NMRAST04 - Packet Sequence Info
NMRDST05 TC Type NMRDST06 TC Sub-type
7.1.21 INCORRECT CHECKSUM EVENT REPORT TELEMETRY
7.1.21.1 Description
This report is generated when a packet has an incorrect check sum.
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7.1.21.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 EID-A Mandatory
Type 1 EID-A Mandatory
Data Field Header Flag 1 EID-A Mandatory
Application Process ID 7 EID-A Specified, 71
Packet Category 4 EID-A Specified, Event = 1
Segmentation Flags NMRDH111 2 EID-A Mandatory
Source Sequence Count NMRDH112 14 Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH112 16
Time NMRAH113 48 Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH115 3 EID-A Specified, Non-Science data
Checksum Flag NMRDH116 1 EID-A Mandatory
Spare NMRDH117 4 EID-A Mandatory
Packet Type NMRDH118 8 EID-A Specified, Telecommand Verification=1
Packet Subtype NMRDH119 8 EID-A Specified, Acceptance Failure = 2
Pad NMRDH110 8 EID-A Specified
Source Data 16 Detailed definition on following page
Incorrect Checksum Event Report Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Global PID NMRAST01 16
Sequence Control NMRAST02 16
Failure Code NMRAST03 16 2
Packet Service Info NMRAST04 16
Received Checksum NMRAST12 16
Computed Checksum NMRAST13 16
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7.1.21.3 Expected Values
A typical output is shown below.
Time (Pkt Typ, STyp) Data1139979.86552 ( 1,2 ) 0000 0002
7.1.21.4 RSDB Entries
Telemetry Packet: YMRST003 - Incorrect Checksum Telemetry Parameters: In table above. Telemetry Parameters that have subparameters are listed below.
NMRAH111 - PckSeqCount
NMRDH111 Segmentation Flag NMRDH112 MR 71/1 SourceSeqCount
NMRAH113 - DataFieldHdr PUS
NMRDH113 MIRO 71/1 Coarse time NMRDH114 MIRO 71/1Fine time
NMRAH114 - MR71/1 DataFieldHdr PUS
NMRDH110 Data field header pad NMRDH115 PUS version number NMRDH116 Checksum flag NMRDH117 Data field header spare NMRDH118 MIRO 71/1 Packet Type NMRDH119 MIRO 71/1 Packet Subtype
NMRAST01 - Global PID
NMRDST01 PID NMRDST02 PctCategory
NMRAST02 - Sequence Counts
NMRDST03 Source NMRDST04 Counter
NMRAST04 - Packet Sequence Info
NMRDST05 TC Type NMRDST06 TC Sub-type
7.1.22 INCORRECT APID EVENT REPORT TELEMETRY
7.1.22.1 Description
This report is generated when a packet has an incorrect application ID.
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7.1.22.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 EID-A Mandatory
Type 1 EID-A Mandatory
Data Field Header Flag 1 EID-A Mandatory
Application Process ID 7 EID-A Specified, 71
Packet Category 4 EID-A Specified, Event = 1
Segmentation Flags NMRDH111 2 EID-A Mandatory
Source Sequence Count NMRDH112 14 Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH112 16
Time NMRAH113 48 Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH115 3 EID-A Specified, Non-Science data
Checksum Flag NMRDH116 1 EID-A Mandatory
Spare NMRDH117 4 EID-A Mandatory
Packet Type NMRDH118 8 EID-A Specified, Telecommand Verification = 1
Packet Subtype NMRDH119 8 EID-A Specified, Acceptance Failure = 2
Pad NMRDH110 8 EID-A Specified
Source Data 16 Detailed definition on following page
Incorrect APID Event Report Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Global PID NMRAST01 16
Sequence Control NMRAST02 16
Failure Code NMRAST03 16 3
Packet Service Info NMRAST04 16
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7.1.22.3 Expected Values
A typical output is shown below.
Time (Pkt Typ, STyp) Data1139979.86552 ( 1,2 ) 0000 0003
7.1.22.4 RSDB Entries
Telemetry Packet: YMRST004 Incorrect APID Telemetry Parameters: In table above. Telemetry Parameters that have subparameters are listed below
NMRAH111 - PckSeqCount
NMRDH111 Segmentation Flag NMRDH112 MR 71/1 SourceSeqCount
NMRAH113 - DataFieldHdr PUS
NMRDH113 MIRO 71/1 Coarse time NMRDH114 MIRO 71/1Fine time
NMRAH114 - MR71/1 DataFieldHdr PUS
NMRDH110 Data field header pad NMRDH115 PUS version number NMRDH116 Checksum flag NMRDH117 Data field header spare NMRDH118 MIRO 71/1 Packet Type NMRDH119 MIRO 71/1 Packet Subtype
NMRAST01 - Global PID
NMRDST01 PID NMRDST02 PctCategory
NMRAST02 - Sequence Counts
NMRDST03 Source NMRDST04 Counter
NMRAST04 - Packet Sequence Info
NMRDST05 TC Type NMRDST06 TC Sub-type
7.1.23 INVALID COMMAND CODE EVENT REPORT TELEMETRY DEFINITION
7.1.23.1 Description
This report is generated when a telecommand contains an invalid command code.
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7.1.23.2 Packet Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Version Number 3 EID-A Mandatory
Type 1 EID-A Mandatory
Data Field Header Flag 1 EID-A Mandatory
Application Process ID 7 EID-A Specified, 71
Packet Category 4 EID-A Specified, Event = 1
Segmentation Flags NMRDH111 2 EID-A Mandatory
Source Sequence Count NMRDH112 14 Zero initially, A separate counter is used for each APID/Packet Category combination (i.e., science, housekeeping, memory dump, etc.)
Packet Length NMRAH112 16
Time NMRAH113 48 Defines the time that the acquisition of the data within the packet was initiated. 4 bytes of seconds followed by 2 bytes of fractional seconds.
PUS Version NMRDH115 3 EID-A Specified, Non-Science data
Checksum Flag NMRDH116 1 EID-A Mandatory
Spare NMRDH117 4 EID-A Mandatory
Packet Type NMRDH118 8 EID-A Specified, Telemetry Verification = 1
Packet Subtype NMRDH119 8 EID-A Specified, Acceptance Failure = 2
Pad NMRDH110 8 EID-A Specified
Source Data 16 Detailed definition on following page
Invalid Command Code Event Report Source Data Definition
Data Element RSDB Name Size (bits) Value (binary) Comment
Global PID NMRAST01 16
Sequence Control NMRAST02 16
Failure Code NMRAST03 16 4
Packet Service Info NMRAST04 16
FC4_Par3 NMRAST14 16
FC4_Par4 NMRAST15 16
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7.1.23.3 Expected Value
A typical output is shown below.
Time (Pkt Typ, STyp) Data1139979.86552 ( 1,2 ) 0000 0004
7.1.23.4 RSDB Inputs
Telemetry Packet: YMRST005 - InvalidCmdCode Telemetry Parameters: In tables above Telemetry Parameters that have subparameters are listed below.
NMRAH111 - PckSeqCount
NMRDH111 Segmentation Flag NMRDH112 MR 71/1 SourceSeqCount
NMRAH113 - DataFieldHdr PUS
NMRDH113 MIRO 71/1 Coarse time NMRDH114 MIRO 71/1Fine time
NMRAH114 - MR71/1 DataFieldHdr PUS
NMRDH110 Data field header pad NMRDH115 PUS version number NMRDH116 Checksum flag NMRDH117 Data field header spare NMRDH118 MIRO 71/1 Packet Type NMRDH119 MIRO 71/1 Packet Subtype
NMRAST01 - Global PID
NMRDST01 PID NMRDST02 PctCategory
NMRAST02 - Sequence Counts
NMRDST03 Source NMRDST04 Counter
NMRAST04 - Packet Sequence Info
NMRDST05 TC Type NMRDST06 TC Sub-type
7.1.24 ADDITIONAL ROSETTA TELEMETRY RELEVANT TO MIRO
NMRASDTA - MIRO SDT SAMP NMRASDTB - MIRO SDT SAMP Redundant NMRAT002 - PAY413 - MIRO Temp 2B NMRAT101 - PAY414 - MIRO Temp 1A NMRAT102 - PAY412 - MIRO Temp 2A
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USE OF THE EQM AFTER LAUNCH
8.1 SUMMARY
The EQM was initially taken back to JPL after launch and installed in a testbed facility at JPL. During the cruise phase it was realized that certain instrument commands, such as software patches, could not be realistically tested in this configuration, as it did not include the PI to ESA and ESA to spacecraft interfaces. Therefore, in late 2010, the MIRO EQM was sent to Darmstadt, Germany, and integrated into the spacecraft EQM. The MIRO EQM was removed from the spacecraft model after the end of flight operations, and will be shipped back to JPL. When at JPL, the EQM is located in Bldg 233-100. The testbed facility includes the entire instrument, S/C simulator, and GSE.
The EQM is mostly functional, however the optics and phase lock loop need additional work to bring the system to the fully operational point. The wire grid diplexer is not installed because of its sensitivity to handling. The testbed facility contains original documentation and spare parts. The telescope is in the facility but not installed on the instrument. The EQM does not have 100% fidelity with the hardware flight instrument, however it is very close. The software installed on the testbed has 100% fidelity.
During flight operations, the EQM testbed was used for trouble shooting the flight instrument, and for checking out software, and telemetry commands including patches. After the end of Rosetta operations, it is intended to keep the EQM for an indeterminate time as a testbed and potential source of parts for future instruments developed by JPL. As the first submillimeter instrument flown in deep space, it is eventually hoped that the EQM will reside in a museum-type display at JPL.
It is the intention of the PI to maintain the JPL testbed facility as long as funding and the facility itself allow. It is not the intention to keep the facility at the 100% operational level.
At the request of ESA, the MIRO testbed facility can be used to troubleshoot problems that are brought to the attention of the PI.
8.2 REQUIREMENTS
There are no special requirements on the testbed. The intent is to keep the EQM in reasonable ready state to be able to trouble shoot the flight instrument. Thus far, this has entailed maintaining an operational flight like computer and power on capability. The optics are not required to be fully functional.
8.3 REQUIREMENTS FOR ESA MANPOWER
None required while the instrument is at JPL.
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SCIENCE DATA
9.1 INTRODUCTION
This chapter is intended to be a reference for users of MIRO science data. It was introduced in Version 4.5 of the Users Manual with just a few monographs addressing topics of interest, with additional Sections added each revision. Topics anticipated to be added in later versions are:
*
Science data products (Currently described in the MIRO Experimenter to Planetary Science Archive Interface Control Agreement, RO-MIR-IF-0001, available via the public Rosetta data archives hosted by ESA's Planetary Science Archive [PSA] and NASA's Planetary Data System [PDS].)
*
Beam pattern
*
Frequency calibration. (Currently summarized in the MIRO Experimenter to Planetary Science Archive Interface Control Agreement, RO-MIR-IF-0001, available via the public Rosetta data archives hosted by ESA's Planetary Science Archive [PSA] and NASA's Planetary Data System [PDS].)
*
Pipeline data processing. (Currently described in the MIRO Experimenter to Planetary Science Archive Interface Control Agreement, RO-MIR-IF-0001, available via the public Rosetta data archives hosted by ESA's Planetary Science Archive [PSA] and NASA's Planetary Data System [PDS].)
*
Special data processing
*
Data quality flags. (Currently described in the MIRO Experimenter to Planetary Science Archive Interface Control Agreement, RO-MIR-IF-0001, available via the public Rosetta data archives hosted by ESA's Planetary Science Archive [PSA] and NASA's Planetary Data System [PDS].)
9.2 ANTENNA TEMPERATURE
Some of MIRO's measurements are reported as an antenna temperature. To understand the meaning of this quantity, it is first necessary to define what is meant by antenna temperature and then to derive an expression for the antenna temperature produced by the MIRO instrument when viewing a thermal calibration target.
9.2.1 DEFINITION OF ANTENNA TEMPERATURE
Antenna temperature is used by the MIRO experiment as a measure of the power delivered by the telescope (when viewing an object) to the millimeter and submillimeter receivers. This units change from Watts to Kelvin is accomplished by defining the antenna temperature as the received power (P, in Watts) received from the source of emission, divided by the bandwidth (d.) of a receiver channel and the Boltzmann constant, k.
Eq. 1
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Note that we are not making the Rayleigh-Jeans approximation (which involves a linear relation between brightness and physical temperature). Equation 1 is a definition of antenna temperature regardless of whether the Rayleigh-Jeans law is valid or not.
The response of the MIRO instrument is linear for the power levels it is expected to encounter. In that case there is a simple relation between antenna temperature and the raw instrument counts that are reported. We use this fact later, but for ease of reference we state it here mathematically as:
Eq. 2
where D is the counts reported by the instrument when observing a source, and G and To are calibration coefficients (gain and offset, respectively) determined from measurements of MIRO's calibration targets. Gain has units of counts/K, and To is in K.
9.2.2 ANTENNA TEMPERATURE OF MIRO CALIBRATION TARGETS
The millimeter and submillimeter MIRO radiometers are both heterodyne receivers having a single polarization receive capability. When viewing a source
of radiation with brightness , the radiometers receive a power (P) in
bandwidth .. equal to
Eq. 3
where
The factor of 1/2 is introduced to account for the single polarization of the MIRO receivers at both wavelengths, and making the assumption that the energy emitted by whatever we are observing, B(.,f), is equally split between the polarizations.
To determine the antenna temperature calibration scale for MIRO, a three position switchable mirror can direct the input of the receivers to either the sky, a warm calibration target, or a cold calibration target. The temperatures of the two calibration targets are measured using platinum resistance thermometers. When viewing the calibration targets, their brightness does not vary strongly over the bandwidth of the MIRO receivers nor does it vary strongly over the beamwidth. In that case we can integrate Eq. 3 over frequency and solid angle and write for the power received by the MIRO receivers
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.h .3 . 1
PA= d..
e . 2 . h. A. c . kT
e -1 where
In this expression for the power, we have substituted the Planck brightness function (as a function of the physical temperature) for the brightness. An important detail to note is that at millimeter wavelengths, the MIRO cold calibration target does not completely fill our beam. This requires us to apply a correction factor which is discussed in MIRO Technical Note 3170, but it is neglected for the tutorial presented here.
We next make use of a relation among antenna effective area, beam solid angle, and the observing wavelength:
which can be derived from equilibrium considerations as discussed in Wilson et al. 2009 (Tools of Radio Astronomy, 5th edition, published by Springer). (Intuitively, one can see that a relation like this is plausible given that for a circular dish collecting area goes as radius squared while the diffraction limited beam size goes as (./radius)2.) Inserting this expression into the equation for received power (assuming no losses), we can write for the received power per Hertz of the calibration target
The power received from the calibration target, expressed as an antenna temperature, can now be written as
Eq. 4
This equation for TA gives the power received from a calibration target but not the antenna temperature from an observed source. To determine the temperature from an observed source, the gain of the receiver needs to be calibrated using the calibration targets and sky, or some combination of the three.
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9.2.3 ANTENNA TEMPERATURE OF A SOURCE OF EMISSION
The MIRO receiver uses a square law detector to measure power. The output of the detector is in counts. In general, the counts are proportional to the sum of the receiver noise power and received power from observed source. When viewing the warm and cold loads, the receiver gains can be calculated from the expressions (see Eq. 2)
Subtracting the two above equations and solving for gain we find
Eq. 5
where DW and DC are the digital counts from the receiver when viewing the warm and cold calibration targets respectively, and TAW and TAC are the antenna temperatures produced by the warm and cold targets respectively, computed from the expressions (Eq. 4)
The units of G are in counts per K (antenna temperature). Since receiver noise power is included in DW and DC , it is removed by taking the difference in the numerator.
In order to compute the antenna temperature of the source, it is necessary to define a reference. For example, if we take the reference to be the number of counts when viewing the warm load (DW), and D the number of counts when viewing the source, then
is the difference in antenna temperature between the source and the warm load. The difference can be positive or negative depending on whether the source is stronger or weaker than the signal power from the warm load. As noted above, the receiver noise power is removed in the subtraction process.
Since the antenna temperature from the warm load is TAW the antenna temperature of the source can be written as
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An alternative expression which uses the cold load as the reference is
Generally we try to use the reference for which
is a minimum. This keeps the interpolation step size to a minimum. Comparing the above expressions to Eq. 2, we can see that the calibration coefficient G is given by Eq. 5, and To can be expressed as either
or, equivalently,
Having both warm and cold load calibration targets allows MIRO to be calibrated even if the boresight is on the target for a long period of time and no "off" measurements are available. Where "off" measurements are available, the gain can be calculated from either of the two additional equations below, where DOFF is the count when observing empty sky and we assume the antenna temperature of empty sky is due to Planck emission from the Cosmic Microwave Background (CMB) at 2.73 K. (Using Eq. 4, the antenna temperature of the CMB, TAcmb, is about 0.3 K in MIRO's millimeter channel, and 1.5E-3 in the submillimeter.)
And these gains can be used to determine antenna temperature with
9.2.4 RELATIONSHIP OF ANTENNA TEMPERATURE TO PHYSICAL TEMPERATURE
Previously we noted that the antenna temperature from a blackbody (emissivity =
1)target at temperature T, which fills the telescope beam, could be written as
where
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The series expansion for TA is given by
x12
TA = T ( 1-+ x - ...)
2 12 xT 1
TA = T-+ Tx2 - ...) = T - Delta
2 12
where xT1 2
Delta = ( - Tx + ...)
2 12
In the limit where x << 1, TA converges to the physical temperature, T, of the target. This is the previously mentioned Rayleigh-Jeans limit, appropriate for low frequencies and high temperatures. This approximation is not valid at the high frequencies and low physical temperature of objects MIRO typically observes, nor are the objects being looked at perfect blackbodies. For this reason, the antenna temperature of an object, even if it fills MIRO's beam, is different than the physical temperature.
The table below shows how the antenna temperature deviates from the target physical temperature for the two frequencies used in the MIRO experiment and for a range of temperatures that the MIRO experiment will be viewing. The parameter x is substantially different from zero under these conditions. It is absolutely necessary to use the full expression (or the series expansion) for P/d. to relate it to physical temperature. It can be noted that for physical temperatures ~50 K and above, the antenna temperatures at 190 GHz and 556.9 GHz are lower than the physical temperatures by about 4.5 K and 12-13 K respectively.
Table 9.2-1: Representative Differences between Physicaland Antenna Temperatures
Frequency(GHz) T -TA
T = 2.7 K T = 50 K T = 100 K T = 150 K T = 300 K
190 2.378 4.421 4.490 4.513 4.536
556.9 2.699 12.179 12.769 12.967 13.165
A final thing to keep in mind when interpreting antenna temperatures is that they are based on the full field of view of the instrument. If an object that fills our beam yields an antenna temperature of 300 K, that same object filling only half of our beam would result in an antenna temperature of 150 K.
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9.3 SPECTROMETER BAND LOCATIONS
9.3.1 INTRODUCTION
The MIRO instrument is designed to simultaneously detect 8 different spectral lines whose rest frequencies are spread across 32 GHz (from an H218O line at
547.7 GHz to a CH3OH line at 579.2 GHz). In order to fit all 8 lines into the 180 MHz bandwidth (4096 channels) of the MIRO spectrometer, the submillimeter receiver contains a series of mixers, amplifiers, and filters that take a spectral region approximately 20 MHz wide around each of the targeted lines, and places them "side-by-side" within the bandpass of the spectrometer. See Section 1.2.2.4 of the MIRO Users Manual for details of how this is done. Section
9.4 of the Users Manual provides equations that relate the true "sky frequency" of spectral features observed to the frequency and channel number at which it appears in the spectrometer. In this section, we will typically use only spectrometer channel number or frequency at the input to the spectrometer (referred to as the intermediate frequency, or IF), instead of trying to refer back to the sky frequency.
Given that the 8 spectral lines being studied have different signal paths into the spectrometer, creating different performance statistics and calibrations, it is convenient to refer to 8 different "bands" within the spectrometer, each associated with a different spectral line. The best way to define each of these bands depends on the intended use. For this reason, MIRO commonly uses three different ways of defining band boundaries. This section summarizes how bands are defined for each approach.
9.3.2 BANDS DEFINED BY IF FILTERS
These band boundaries are appropriate to use when one is interested in knowing from what sky frequencies most of the observed power is coming. These bands are specified by IF frequency, as that is the parameter defining the filters.
The MIRO spectrometer takes as input frequencies in the range of approximately 1260 to 1440 MHz (the exact frequencies being temperature dependent, as described in Section 9.4). The Intermediate Frequency Processor, or IFP, places the 8 spectral lines of interest across this frequency range as described in Section
1.2.2.4. To minimize noise from one spectral region of interest interfering with the signal from a neighboring spectral region, the IFP contains relatively narrow-band ceramic filters placed just before the 7 signal paths through the IFP are fed to the spectrometer. See Figure 1.2-6; the filters referred to are near the right side of the figure, just before the power combiner. Note that there are only 7 filters but 8 spectral lines are observed. This is because the IFP design places two spectral lines side-by-side at IF, allowing a single filter to pass both.
Figure 9.3-1 shows the normalized transmission of each filter as a function of IF (the black solid lines). For reference, it also shows the emission from the targeted spectral lines (blue dashed lines) for a simple comet model. The model is described in detail at the end of this section. Each molecule's line appears twice due to frequency switching, with the plus 5 MHz setting shown as short dashes,
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the minus 5 MHz setting shown as long dashes. Labels identify each species observed.
If every sky frequency observed by MIRO contained the same amount of power, and the instrument were perfectly calibrated, the points at which the normalized transmission of each filter are equal would mark the boundaries between bands. The equations of Section 9.4 could then be used to calculate the sky frequency from which most of the emission is coming within each band. These cross-over points are listed in Table 9.3-1. See MIRO Technical Note TN3067 for additional discussion of this. The pseudo-SNR approach discussed in that document yields cross-over points identical to those given here to within 0.1 kHz.
representative spectral lines.
Table 9.3-1: Band Boundaries Defined by the IFP Narrow-Band Filters.
BAND H2O H217O Me1103 H218O
Low High Low High Low High Low High
IF Freq. (MHz) 0 1290.0259 1290.0259 1309.9692 1309.9692 1329.9922 1329.9922 1349.9764
BAND CO Me87 NH3 / Me542
Low High Low High Low High
IF Freq. (MHz) 1349.9764 1378.9721 1378.9721 1398.9950 1398.9950 8
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In the above table, note that the lowest and highest frequencies are listed as 0 and infinity. This is because there is no adjacent filter to "cross-over" on the low and high sides of the spectrometer input. Instead, the IF frequency associated with the first and last spectrometer channel-as calculated using expressions in Section 9.4-should be used for band boundaries. Those frequencies are temperature dependent, but the low-and high-frequency limits will be near 1260 and 1440 MHz, respectively.
For future reference, the model spectra shown in Figure 9.3-1 assume a spherically symmetric nucleus and coma, producing 1.0 x 1028 water molec/sec moving radially at 1 km/s. The nucleus radius is 1 km, and the instrument line-of-sight is taken to be limb-sounding the nucleus (impact parameter 1.2 km) from 1000 km away. Coma gas temperature (kinetic and excitational) is 100 K. The abundance of the species, relative to water, is assumed to be:
17O
H2=4.0 x 10-4 18O
H2=2.0 x 10-3
CH3OH = 0.04
CO = 0.05
NH3 = 0.01
The brightness temperature plotted is a Rayleigh-Jeans temperature. These model calculations were made in 1999 using radiative transfer software originally developed by R. Redman and modified by M. Hofstadter.
9.3.3 BANDS DEFINED FOR PERFORMANCE MONITORING
These bands are used when one desires to identify spectrometer channels that are associated with one of our targeted spectral lines, but whose signal comes from only one path through the IFP. This selects channels with the most accurate calibration and whose signal comes from well-defined sky frequencies. These bands are specified by spectrometer channel number.
In Section 9.3.2 we defined bands based upon the idealized case of a spectrally uniform signal and perfect calibration. In almost all observational situations those conditions are not met. This is particularly true near the IF filter cross-over points, where power may be coming from either of two signal paths through the IFP. For this reason some of the MIRO data analysis software focuses only on channels likely to contain a targeted line but well-away from the filter cross-over points shown in Figure 9.3-1. For example, we track the mean and rms values within each band-center when looking at one of our calibration loads as a quick check of performance.
Table 9.3-2 lists band boundaries typically used for this type of performance monitoring. The limits are somewhat arbitrary, and changes of 10 channels (~0.4 MHz) are unlikely to be significant. Note that 8 bands are defined, unlike the filter-based bands described in the previous section. This allows us to monitor channels associated with each of the 8 targeted spectral lines. Note that
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spectrometer channel number increases as frequency decreases, so the lowest IF frequency band (containing the H2O line) has the highest channel numbers. Note also that spectrometer channel numbers are zero-based.
Table 9.3-2: Performance Monitoring Bands
Band H2O H217O Me1103 H218O CO Me87 NH3 Me542
Low Hi Low Hi Low Hi Low Hi Low Hi Low Hi Low Hi Low Hi
Channel (Zero-based) 3769 4024 3069 3324 2637 2892 2197 2452 1665 1920 1073 1328 669 924 253 508
The channel numbers in Table 9.3-2 assume one is considering a full-resolution spectrum, which is the default output of MIRO. The instrument can be commanded to do on-board spectral smoothing and then return fewer than 4096 channels. See Section 6.1.2.1.4.2 for a description. When looking at smoothed spectra, the above channel numbers should be adjusted accordingly.
9.3.4 BANDS DEFINED FOR ON-BOARD DATA COMPRESSION
These bands are used by the on-board software as part of MIRO's data compression scheme, and should be transparent to the average user.
One of the ways MIRO's on-board software compresses the spectrometer data for downlink is to divide each spectrum into bands based on channel number, which are roughly aligned with the filter cross-over points of Section 9.3.2. Only the 12 most significant bits used in a band are reported for each channel of that band. Details of this are described in Section 6.1.5.7. Table 9.3-3 lists the band boundaries used for this purpose. Note that channel numbers are zero-based.
Table 9.3-3: On-Board Data Compression Bands
Band H2O (Band 6) H217O (Band 5) Me1103 (Band 4) H218O (Band 3) CO (Band 2) Me87 (Band 1) NH3 / Me542(Band 0)
Low Hi Low Hi Low Hi Low Hi Low Hi Low Hi Low Hi
Channel (Zero-based) 3371 4095 2916 3370 2458 2915 2002 2457 1339 2001 881 1338 0 880
The channel numbers in Table 9.3-3 assume one is considering a full-resolution spectrum, which is the default output of MIRO. The instrument can be commanded to do on-board spectral smoothing and then return fewer than 4096 channels. See Section 6.1.2.1.4.2 for a description. When looking at smoothed spectra, the above channel numbers should be adjusted accordingly.
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9.3.5 BAND DEFINED FOR SPECTRAL BASELINE REMOVAL
In some MIRO spectral data products a baseline is subtracted from the
data as described in Section 9.5.2. The baseline is defined on the
so-called "interpolated" IF grid used in that data set. For
completeness, the discussion of bands in that section is repeated here.
In MIRO Pipeline Software Version 3.0 (used to generate Level 3 Version
3 products), the spectral baseline is removed from the spectra
generated by Software Version 2.0. Note that we use the "common
frequency grid," also referred to as the interpolated frequency grid,
in Version 3 products. (The frequency response of MIRO's spectrometer
is temperature dependent--see Section 9.4.3--so the common frequency
scale interpolates all observations to the same intermediate
frequencies.) The region around each of the 8 spectral lines observed
is treated independently, and each spectrum is treated independently.
As is commonly done with spectral data, channels on either side of the
emission feature are used to estimate a linear spectral baseline having
slope and intercept, and this linear function is subtracted from the
spectral region. This results in the spectral line apearing in a flat
baseline with zero average brightness. Table 9.5-2 provides details on
what channel numbers are associated with each spectral feature for
purposes of calculating a baseline. With two exceptions, the baseline
is calculated by averaging the lowest 10% of the channel numbers in a
band and the highest 10% of the channel numbers, and fitting a line to
those two points. The first exception involves Band 1, the H2O line. In
this case, the highest 15 channel numbers are ignored, due to those
channels almost always containing no data (only when the CTS is at an
unusual temperature are those frequencies sampled). The second
exception involves Band 6, which contains both a CH3OH line and an NH3
line, with the NH3 line appearing at the lowest edge of the band. For
this band, channels 754 to 804 are used to calcualte the
low-channel-number baseline point, and the same linear fit is used for
both lines.
Table 9.3-4: Bands Used for Spectral Baseline Subtraction in Level 3
Version 3 Products.
*See text for special considerations regarding Bands 1 and 7.
This discussion of bands used to calculate spectra baseline in the
Interpolated Frequency grid is repeated as Section 9.5.2.
9.4 MAPPING SKY FREQUENCY TO SPECTROMETER CHANNEL NUMBER
9.4.1 INTRODUCTION
The submillimeter (smm) receiver on MIRO includes both a broadband continuum channel and a high resolution spectroscopic backend that utilizes a Chirp Transform Spectrometer (CTS). Spectral Power data from the CTS are recorded and presented by a channel number running from 0 to 4095. In this section, we will describe how spectral power at the input frequencies are mapped into channel numbers at the output of the CTS.
The RF Input from the telescope is combined with the Local Oscillatory (LO) signal at frequency flo in the Mixer. The mixer down-converts the RF Input signal to an intermediate frequency (IF) signal which is then fed into a low noise amplifier (LNA). The signal at the 1st IF frequency, fif, arises from signal frequencies both greater than and less flo, namely (flo -fif ) and (flo + fif ). Receivers whose first IF frequencies contain RF signal frequencies both greater than and less than the LO frequency are called Double Sideband receivers. It is common to say that the RF spectrum has been folded. The important point to remember is that a single frequency in the IF spectrum originates from two different frequencies in the RF spectrum. In the MIRO receiver, the IF spectrum covers a frequency range from 5 GHz to 16 GHz. The overall frequency coverage in the RF is 22 GHz, divided between two frequency bands.
Following amplification, the IF signal is fed into a complex processor module called the Intermediate Frequency Processor or IFP. The IFP extracts small frequency segments from the IF band and shifts their frequencies so that all of the frequency segments are contiguous and covering ~180 MHz. The frequency segments are chosen to contain the 8 spectral lines of interest for the MIRO instrument. The 8 spectral lines are given in Table 1.1-1 and repeated below.
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Table 9.4-1: The Eight Molecular Transitions Observed by MIRO
Species Frequency (MHz) Transition
Water H216O H217O H218O 556936.002 552020.960 547676.440 1(1,0)-1(0,1) 1(1,0)-1(0,1) 1(1,0)-1(0,1)
Carbon Monoxide CO 576267.9305 J(5-4)
Ammonia NH3 572498.3784 J(1-0)
Methanol CH3OH CH3OH CH3OH 553146.296 568566.054 579151.005 8 (1)--7 (0) E 3 (-2)--2 (-1) E 12 (-1)--11(-1) E
The output frequency band from the IFP is fed directly into the CTS where the spectral power in the 180 MHz band is determined and output in each of the 4096 channels or bins of the CTS. To determine how RF spectral power at the input to the telescope is mapped into channel numbers at the output of the CTS, it is necessary to know the mapping algorithms used in the 1) heterodyne receiver,
2) the IFP, and in the CTS. Items 1 and 2 can be lumped together into a single algorithm for each band.
9.4.2 ALGORITHMS TO CONVERT RF FREQUENCY BANDS TO THE IFP OUTPUT FREQUENCIES
The frequency conversions used in the MIRO receiver are accomplished using a fixed local oscillator frequency and three synthesizer frequencies, all locked to the ultra-stable oscillator on USO. Table 9.4-2 gives the frequencies used.
Table 9.4-2: Frequency Oscillators Internal to MIRO
Name Frequency (GHz) Note
LO 562.813 Local Oscillator Frequency (LO)
S1 2.182 IFP Synthesizer #1
S2 7.147 IFP Synthesizer #2
S3 7.728 IFP Synthesizer #3
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Table 9.4-3 provides the primary list of molecules targeted in the MIRO experiment and RF frequency ranges mapped into the output of the IFP.
Table 9.4-3: RF (Sky Frequencies) Targeted by MIRO
ID # Molecule Line Center Frequency (MHz) RF Band (MHz) Notes
1 H2-16O 556936.002 556916.00 556956.002
1 568670.000 568710.000 Image Band
2 H2-17O 552020.960 552011.960 552031.960
2 573594.040 573614.040 Image Band
3 ME-1103 579151.005 579141.003 579161.003
3 546464.997 546484.997 Image Band
4 H2-18O 547676.440 547666.440 547686.440
4 577939.560 577959.560 Image Band
5 CO 576267.9305 576253.431 576282.431
5 549343.569 549372.569 Image Band
6 ME87 568566.054 568556.055 568576.055
6 557049.945 557069.945 Image Band
7 NH3 572498.3784 572468.433 572509.433
7 553116.567 553157.567 Image Band
8 ME542 553146.296 553116.567 553157.567
8 572468.433 572509.433 Image Band
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Table 9.4-4: RF (Sky Frequencies) to IF Frequency
ID # RF Bands (MHz) Algorithm to Map RF frequencies (GHz) into CTS input frequencies (GHz)
1 556916.002 556956.002 ABS(S2-ABS(freq-LO))
1 568670.000 568710.000
2 552011.960 552031.960 ABS(S3-ABS(2*S1-ABS(freq-LO)))
2 573594.040 573614.040
3 579141.003 579161.003 ABS(S3-ABS(2*S1+ABS(S2-ABS(S2-ABS(freq-LO)))))
3 546464.997 546484.997
4 547666.440 547686.440 ABS(S2-ABS(S1-ABS(S2-ABS(freq-LO))))
4 577939.560 577959.560
5 576253.431 576282.431 ABS(S3-ABS(2*S1-ABS(freq-LO)))
5 549343.569 549372.569
6 568556.055 568576.055 ABS(2*S1-ABS(freq-LO))
6 557049.945 557069.945
7 572468.433 572509.433 ABS(S3-ABS(S3-ABS(2*S1+ABS(freq-LO))))
7 553116.567 553157.567
8 553116.567 553157.567 ABS(S3-ABS(S3-ABS(2*S1+ABS(freq-RLO))))
8 572468.433 572509.433
9.4.3 ALGORITHMS TO CONVERT CTS CHANNEL NUMBER INTO IF INPUT FREQUENCY
The CTS uses SAW devices and these are temperature dependent. The SAW devices have been calibrated by injecting signals of a given frequency into the CTS and observing the output channel as a function of the SAW device temperature. A MIRO Technical Memo (authored by S. Gulkis and C. Backus) describes the resultant algorithm which is summarized here.
The IF input frequency (F in MHz) corresponding to a given channel number using the equation
F = a T+ b N+ c N T+ d
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where F = IF input frequency in MHz, T = temperature of the SAW devices specified in the MIRO data base as spect_t1, N = Bin or Channel number ranging from 0 - 4095. a, b, c, and d are fitted parameters given in the following table.
Table 9.4-5: Parameters Relating CTS Channel to Frequency
Parameter Units Value Std Error
a MHz per deg C -0.0996154 2.0E-4
b MHz per Channel -0.0443027 4.2E-6
c MHz per (Channel-deg C) 7.66259E-6 8.9E-8
d MHz 1443.27
9.4.4 ALGORITHM TO CONVERT CTS INPUT FREQUENCY TO RF FREQUENCY
In order to convert the CTS input frequency to the RF frequency, we first have to divide the 4096 channel band into 8 bands.
When the SAW temperature is 67.9 C, the band boundaries for the 8 bands are given in Table 9.4-6. The table also lists the center frequency of each band in the CTS input frequency and RF frequency. Note that there is no filter separating Bands 7 and 8, so their lower and upper bounds, respectively, are not defined.
For each band, the equation to convert the CTS input frequency to the RF frequency is given as follows:
RF(N, T) = [FGHz(N, T) - IFcenter(N, T)]*direction + RFcenter
where RF(N,T) is the RF frequency, F(N,T) is the CTS input frequency in GHz, IFcenter (N, T) is the CTS input center frequency of the band, and RFcenter is the RF center frequency of the band.
Table 9.4-6: Band boundaries, RF and IF Center Frequencies, and Direction Factor forConversion Between the IF and RF Frequency
Band Molecule RF Center (GHz) IF Center (GHz) Lower Channel Upper Channel Direction
1 H216O 556.936 1.270 3388 4095 1
2 H217O 552.021 1.300 2924 3306 1
3 CH3OH 579.151 1.320 2457 2843 -1
4 H218O 547.676 1.339 2018 2399 1
5 CO 576.268 1.363 1359 1933 1
6 CH3OH 568.566 1.389 881 1263 1
7 NH3 572.498 1.407 * 879 -1
8 CH3OH 553.146 1.425 0 * 1
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9.5 MIRO CALIBRATION
9.5.1 INTRODUCTION
Section 9.5 summarizes the radiometric calibration of MIRO. It first provides a concise summary of the algorithms used (Section 9.5.2) and then includes a longer monograph on the radiometric stability of the system and alternative calibration approaches (Section 9.5.3).
9.5.2 RADIOMETRIC CALIBRATION SUMMARY
The MIRO instrument is calibrated on a periodic basis and immediately following every mode change. An automatic calibration will take place every 1895 seconds (approximately 32 minutes), if not interrupted by a mode change command, which triggers a calibration immediately. The normal interval of 1895 seconds allows 95 seconds for the calibration and 1800 seconds (30 minutes) for the data collection period. The 1800 seconds allows for complete CTS integration periods of 30, 60, 90, and 120 seconds (60, 30, 20, and 15 output spectra respectively). The 95 seconds of calibration data are distributed as follows:
Table 9.5-1: Allocation of Time in a Calibration Sequence.
Time Activity
5 3 mirror movements/no data collection
30 Warm load position-CTS + continuum + engineering
30 Cold load position -CTS + continuum + engineering
30 Sky position -CTS + continuum + engineering
These calibration data are included in the CODMAC Level-2 data files as part of the time sequence. They are flagged by a Calibration field in the header columns.
Each calibration sequence includes collecting 30 seconds of data on an internal warm calibration target, 30 seconds on an internal cold calibration target, and 30 seconds on the sky wherever the instrument boresight is pointed during the sequence. The continuum Summation parameter and, if in a spectroscopic mode, the CTS Smoothing parameter, are applied during calibration observations. If the CTS is on, frequency switching is performed during calibration observations but-unlike during normal science observations-the two LO settings are not subtracted from each other. Instead one spectrum is returned for each of the two LO settings (each representing a 15-second integration). Thus there are two spectra returned on the warm load, two from the cold load, and two on the sky. The number of continuum packets returned on each calibration target depend on the Summation parameter: three are returned for Summation=0, two for Summation=1, and one for Summation=2 or 3. These data are used to determine the relation between instrument counts and absolute flux units. Flux is reported as a Rayleigh-Jeans brightness temperature in Kelvin. The brightness temperature is related to, but not the same as, the physical temperature of the target (see Section
9.2 for a detailed discussion).
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The instrument response is assumed to be linear, so that the relation between recorded counts, D, and brightness temperature, T, is
(Eq. 1)
where g is the gain in counts per Kelvin, and I is the intercept in counts. Since the physical and hence the brightness temperatures of the warm and cold calibration targets are known (see below), and using the subscript H to refer to the warm load and C to the cold, a calibration sequence can be used to determine the gain and intercept by these equations:
(Eq. 2)
(Eq. 3)
calibration parameters.
The above equations are used to determine the calibration parameters at the time of each calibration cycle. These will be referred to as the "instantaneous calibration parameters." For continuum data, the "D" in Equations 1 and 2 is the average number of counts reported while observing each load (and hence may average multiple packets depending on the Summation value), with LO0 and LO1 data averaged separately. For spectroscopic data, the two LO settings are averaged together, but calibration parameters for each channel are calculated independently.
Instantaneous gains are not calculated when there is no engineering data from within 2 minutes of the calibration cycle. In addition, instantaneous continuum gains whose values deviate significantly from expected values are not used (mm gains < 4.0 counts/K or > 6.0 counts/K; submm gains < 1.45 counts/K or > 1.7 counts/K). As discussed in Section 9.5.3, smoothing of the instantaneous gains before applying them to the science data results in a better science product. Smoothing of the continuum and CTS data are handled differently.
A SPECIAL NOTE ON THE COLD-LOAD TEMPERATURE
As discussed in Appendix A, when looking at the cold load, the MIRO
millimeter-wavelength beam picks up some signal from the surrounding
structure. Therefore, an effective cold-load temperature is used for
the calculation of the mm calibration parameters:
(Eq. 4)
where TC and TOpticalBench are the cold load and optical bench
temperatures recorded in MIRO engineering data, and w represents the
fraction of the millimeter signal arising from the load. In MIRO
software version 1 and 1.1, w is taken to be 0.910. In software
versions 2.0 and 3.0, it is 0.925. This correction is only applied when
working with millimeter data.
APPLYING CONTINUUM GAINS TO SCIENCE DATA
In Software Versions 1.0, 1.1, and 2.0
For calibrated continuum science data generated by MIRO's Pipeline software Version 2.0 , gain as a function of time is calculated in a two-step process. First, the instantaneous gains are box-car smoothed: at the time of a calibration, 16 instantaneous gains before and 16 after are averaged with the instantaneous gain at that time. This results in an averaged-gain at the time of each calibration cycle. Second, for the start time of each continuum science packet, a least-squares quadratic fit is made to the 16 box-car-smoothed gains nearest the start time (nominally 8 before and 8 after) to determine a gain versus time curve, and that gain curve is used in the calibration equation. A single gain value is used for all continuum science values in a packet. A similar process is used to determine the intercept as a function of time, except that 1) The instantaneous intercepts are not box-car smoothed, 2) The box-car smoothed gain values are used in Eq. 3 to generate a new instantaneous intercept, and 3) A linear fit to the 4 nearest
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instantaneous intercepts is used (nominally 2 before and 2 after the science data). When in a spectroscopic mode (which means frequency-switching is applied), the calibration parameters for LO0 and LO1 are calculated separately and applied separately to the LO0 and LO1 continuum science data. For simplicity, even when not in a spectroscopic mode, the continuum gains are calculated and applied as if frequency switching were active.
For completeness, we note that in Versions 1.0 and 1.1 of the continuum calibration, no box-car smoothing was applied, and a linear interpolation in time between the one calibration immediately preceding a science observation and the one immediately after were used to calculate both gain and offset. This older calibration algorithm adds noise to the calibrated data because the instrument gain is more stable than the measurement precision of an instantaneous gain calculation.
In Software Version 3.0
Note that observations of empty sky calibrated with both Versions 1 and
2 of the software typically show a brightness of about 1.6 K in the
submm, and -0.5 K in the mm channel. Expected values of the cosmic
microwave background are about 0 and 0.5 K in the submm and mm,
respectively, so the MIRO values are in error. While the magnitude of
this error is smaller than nominal instrument requirements (3K absolute,
see Table 1.2-1) the fact that it appears to be systematic suggests a
correction can be applied. There are several possible causes for this
small offset, including non-linearities in the MIRO detectors
(discussed further in Appendix A), hot- and cold-load emissivities not
being 1.0, temperature gradients within the calibraiton targets, or
unmodeled optical effects witin the instrument or telescope. Whatever
the cause or causes, the correction is expected to be smallest when
observing objects whose temperature is near that of the hot- and
cold-load calibration targets, and largest when observing empty sky.
MIRO Pipeline Software Version 3.0 (used to generate Level 3 Version
3.0 products) therefore applies an additive correction to the continuum
temperatures generated by the Version 2 software. The correction is
linear in scene temperature, having a value of 0.0 at the average of
the hot and cold load measured physical temperatures, but when looking
at empty sky the correction has its maximum amplitude, chosen to make
the observed temperature match the expected cosmic background value.
The correction added to the Version 2 continuum temperatures is given
by.
(Eq. 5)
where T is the Version 2 calibrated continuum temperature, TH and TC
are the hot- and cold-load physical temperatures, respectively, TpS is
the Version 2 temperature found when looking at empty sky (described
below), and TS is the expected sky temperature (0.001 K and 0.33 K for
the submm and mm, respectively). To determine the value of TpS for each
continuum data record, we first find all Version 2 calibrated continuum
records, within +-2 days of the record to be calibrated, whose average
value is less than 3 K (each continuum data record typically contains
200 continuum samples spanning a total of 10 seconds in time). This is
our initial filter to find empty sky measurements. We then fit a
Gaussian to the distribution of candidate empty sky observations, and
use the peak of the Gaussian as the value of TpS. This fitting process
further reduces measurement noise and helps filter out the relatively
small number of sky observations made close enough to the nucleus to be
slightly "contaminated" by emission from the nucleus or coma dust. (We
also tested algorithms that filtered sky data by distance from the
nucleus, and we performed spot checks against the Gaussian fitting process.
The two approaches give similar results, so we use the Gaussian as it
is computationally easier.) Note that this
process allows for time variations in the correction factor. A single
record of MIRO continuum data contains many measurements which,
depending on the instrument's summing value (which controls integration
times) span 10 to 200 seconds in time. This time range is small
compared to the averaging time used to calculate TpS, so the same TpS
value is used for correcting all continuum measurements in a record..
APPLYING CTS GAINS TO SCIENCE DATA
In Software Versions 1.0, 1.1 and 2.0
For calibrated spectroscopic science data generated by MIRO's Pipeline software Version 2.0 (the latest available as of January 2018), each of the 4096 CTS channels is calibrated independently. For reasons discussed below, the Intercept in Eq. 1 is taken to be zero. Because of frequency switching, a science spectrum incorporates data at both LO settings, so for CTS purposes the instantaneous gain is taken to be the average gain of the two LO settings.
The gain at the time of a science observation is taken to be one-half of the average gain of the nearest 32 instantaneous gains. The factor of 1/2 (effectively increasing the reported brightness temperature) is due to the fact that MIRO is a double-sideband system. (MIRO measures the total power received in two frequency bands, an upper and a lower sideband. When looking at a continuum target, such as the comet nucleus or a calibration target, roughly equal amounts of power are received in each sideband. A spectral line, however, only exists in one of the sidebands, so the effective CTS gain for that line is only half of what it is for the calibration signal which exists in both sidebands.)
In a perfect instrument, frequency-switched spectra would have a baseline brightness (where there is no spectral feature from the comet) of 0 K. Due to a systematic offset between the calibration parameters at each LO setting, differenced spectroscopic data typically have a small positive bias, with the baseline being at about 2 K. (The rms scatter in a typical 30-second spectrum is larger than this. See Section 9.7 for a discussion of error bars associated with calibrated data.) This baseline also can vary in some IF frequency bands (defined in Section 9.3.2) due to an amplifier instability. We leave these non-zero baselines in the calibrated data because they may be of interest for future engineering uses. For science purposes, however, it is appropriate to estimate the baseline around each spectral feature in a band and subtract that value from all channels in the band, giving it a zero baseline.
For completeness we note that earlier versions of calibrated CTS data,
instead of averaging instantaneous gains, just used a linear
interpolation in time to calibrate each science spectrum. As with the
continuum data, this unnecessarily added noise, so the newer algorithm
should always be used.
In Software Version 3.0
In MIRO Pipeline Software Version 3.0 (used to generate Level 3 Version
3 products), the spectral baseline is removed from the spectra
generated by Software Version 2.0. Note that we use the "common
frequency grid," also referred to as the interpolated frequency grid,
in Version 3 products. (The frequency response of MIRO's spectrometer
is temperature dependent--see Section 9.4.3--so the common frequency
scale interpolates all observations to the same intermediate
frequencies.) The region around each of the 8 spectral lines observed
is treated independently, and each spectrum is treated independently.
As is commonly done with spectral data, channels on either side of the
emission feature are used to estimate a linear spectral baseline having
slope and intercept, and this linear function is subtracted from the
spectral region. This results in the spectral line apearing in a flat
baseline with zero average brightness. Table 9.5-2 provides details on
what channel numbers are associated with each spectral feature for
purposes of calculating a baseline. With two exceptions, the baseline
is calculated by averaging the lowest 10% of the channel numbers in a
band and the highest 10% of the channel numbers, and fitting a line to
those two points. The first exception involves Band 1, the H2O line. In
this case, the highest 15 channel numbers are ignored, due to those
channels almost always containing no data (only when the CTS is at an
unusual temperature are those frequencies sampled). The second
exception involves Band 6, which contains both a CH3OH line and an NH3
line, with the NH3 line appearing at the lowest edge of the band. For
this band, channels 754 to 804 are used to calcualte the
low-channel-number baseline point, and the same linear fit is used for
both lines.
Table 9.5-2: Bands Used for Spectral Baseline Subtraction in Level 3
Version 3 Products.
*See text for special considerations regarding Bands 1 and 7.
This discussion of bands used to calculate spectra baseline in the
Interpolated Frequency grid is repeated as Section 9.3.5.
9.5.3 A MONOGRAPH ON MIRO CALIBRATION
Please see Appendix A for MIRO Co-Investigator F. Peter Schloerb's monograph on MIRO calibration.
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9.6 MIRO BORESIGHT AND GEOMETRY DATA PRODUCTS
9.6.1 MIRO BORESIGHT
The MIRO instrument is rigidly mounted to the spacecraft. During spacecraft assembly, an attempt was made to align the spacecraft and instrument z-axes. Each MIRO receiver (SubMM and MM) has its own beam pattern and boresight. Observations of Venus soon after launch, and of the Moon during the Earth flybys, were used to test the alignment. Various scans across Venus and the Moon were made, and the data were compared to model calculations to determine in a least-squares sense the best fit to each MIRO boresight axis relative to the spacecraft z-axis. Ultimately, the Moon data were decided to be the most reliable, and the following offsets determined assuming spherically symmetric, Gaussian beam patterns:
Instrument Offset from Zs/calong Xs/c (deg) Offset from Zs/calong Ys/c (deg) Assumed Beam Shape
MIRO SubMM -0.082 +/- 0.005 -0.0067 +/- 0.005 Circular Gaussian-shaped beam with full width at half power (HPBW) = 0.125 deg.
MIRO MM -0.018 +/- 0.025 -0.057 +/- 0.025 Circular Gaussian-shaped beam with full width at half power (HPBW) = 0.395 deg.
See the Rosetta Project document RO-EST-TN-3305 for additional information on the boresight alignment of all Rosetta instruments.
During analysis of MIRO data at the comet, however, it is seen that the beam is routinely offset relative to the comet from where it is expected to be. Figure 9.6-1 shows an analysis of 91 raster maps of the nucleus made in 2015. For each observed map, a model of the nucleus (based on shape model OSIRIS_SHAP7_1.6) is fit to the map. The nucleus appears displaced in both the millimeter and submillimeter beams by a similar amount. At the time of this writing (August 2017), we cannot say what causes this residual offset. Possibilities include a potentially time-varying MIRO alignment, flexing of the spacecraft, or errors in the spacecraft or comet ephemerides. It should be noted that other instruments report pointing offsets of similar magnitude, and the Rosetta Project is investigating. We conclude that
*
Using the MIRO boresight alignment information given in the above table, along with the Rosetta Project's reconstructed SPICE kernels (described in Section 9.6.2), can result in MIRO's beams being-relative to the comet-
0.025 degrees (1.5 arcsec) away from their expected location.
*
The relative positions of the MIRO millimeter and submillimeter beams are, however, accurate to 0.0017 degrees (0.1 arcsec).
*
In 2015, the residual offset can be corrected for by assuming the MIRO submillimeter beam has an additional offset from the above tabulated values of 0.0223 +/- 0.0042 degrees (1.34 +/- 0.25 arcsec) along the spacecraft x-axis
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and -0.0033 +/- 0.0058 degrees (-0.2 +/- 0.35 arcsec) along the spacecraft y-axis. The millimeter beam has offsets of 0.0223 +/- 0.0057 degrees (1.34 +/- 0.34 arcsec) along the spacecraft x-axis and -0.0053 +/- 0.0068 degrees (-0.32 +/-
0.41) arcsec along the spacecraft y-axis.
We have not performed this anaysis for any other years, and cannot speculate on systematic pointing offsets at other times.
9.6.2 MIRO GEOMETRY DATA PRODUCTS
Some MIRO data archived in the PSA/PDS includes geometry information. This section gives a brief summary of the geometry information provided at the comet.
PRELIMINARY VERSIONS OF GEOMETRY DATA PRODUCTS
Geometric information produced by early versions of MIRO's Pipeline software were calculated assuming the comet nucleus was a tri-axial ellipsoid. These quantities should be ignored in favor of later data products. Do not use geometry information contained in data records with the SW_VERSION parameter set to
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1.0 or 1.1. In the PSA/PDS archive, this includes all CODMAC Level 3 data sets whose directory names include V1.0. An example is
RO-C-MIRO-3-ESC1-67P-V1.0
where the "3" in the directory name indicates it is a CODMAC Level 3 product, and V1.0 indicates it is the first data set of that level for the ESC1 mission phase delivered for public release. Note that the version number in the PSA/PDS directory names is different from the MIRO Pipeline software version number that generated the data products.
GEOMETRY DATA PRODUCTS FROM MIRO SW_VERSION=2.0
Geometric information tagged with SW_VERSION=2.0 within the data records have been calculated using a nucleus shape model provided by the OSIRIS team, and designated OSIRIS_SHAP7_1.6. Because other versions of the MIRO software may use other shape models, the field SHAPE_VERSION is contained with the geometry data records. It is an integer indicating the shape model used, and its definition will be updated over time. As of August 2017, possible values of SHAPE_VERSION and the corresponding shape model used are:
1 = SHAP5-v0.3
2 = SHAP5-v1.2;
3 = OSIRIS_SHAP7_1.6
4 = OSIRIS_V_1.1
In addition to a shape model, various comet, spacecraft, and instrument ephemerides are needed to calculate geometric parameters. SPICE kernels provided by the Rosetta Project are used. As with the nucleus shape model, various versions of the SPICE kernels were generated over time. This includes preliminary versions developed for mission planning purposes and so-called "reconstructed" kernels developed after-the-fact. In SW_VERSION 2.0 records, the best available reconstructed kernels, as of August 2017, were used. (Note that these kernels do not account for the residual pointing offsets discussed at the very end of Section 9.6.1.) The field SPICE_KERNEL_VERSION within a geometry data record is an integer identifier for a particular set of kernels:
2014 indicates:
CORB_DV_145_01_______00216.BSP ROS_140501_STEP.TSC DE405.BSP ROS_160929_STEP.TSC EARTHFIXEDIAU.TF ROS_CGS_RSOC_V03.TPC NAIF0010.TLS ROS_MIRO_V10.TI NAIF0011.TLS ROS_V26.TF RATT_DV_145_01_01____00216.BC RS_ROT_PARAM_20m.tpc RORB_DV_145_01_______00216.BSP
2015 indicates:
CORB_DV_185_01_______00261.BSP ROS_140501_STEP.TSC DE405.BSP
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ROS_160929_STEP.TSC EARTHFIXEDIAU.TF ROS_CGS_RSOC_V03.TPC NAIF0010.TLS ROS_MIRO_V10.TI NAIF0011.TLS ROS_V26.TF RATT_DV_185_01_01____00261.BC RS_ROT_PARAM_20m.tpc RORB_DV_185_01_______00261.BSP
2016 indicates:
CORB_DV_257_02_______00344.BSP ROS_160929_STEP.TSC DE405.BSP ROS_CGS_RSOC_V03.TPC EARTHFIXEDIAU.TF ROS_MIRO_V10.TI NAIF0011.TLS ROS_V26.TF RATT_DV_257_02_01____00344.BC RS_ROT_PARAM_20m.tpc RORB_DV_257_02_______00344.BSP
As of August 2017, the only PSA/PDS data sets generated with MIRO Pipeline SW_VERSION=2.0 are ones designated as CODMAC combined Level 3 and 4 Version 1.0. A sample directory name is RO-C-MIRO-3-4-EXT1-67P-V1.0, where it must be remembered that the version number in the PSA/PDS directory names is not the same as the MIRO SW_VERSION field used to generate the data.
The geometry parameters calculated by the SW_VERSION=2.0 MIRO software include:
BS_X_ANG: Angle between MIRO boresight and comet center projected on the MIRO x-axis (-360 to +360 deg with positive angles measured counterclockwise from the x-axis towards the y-axis).
BS_Y_ANG: Angle between MIRO boresight and comet center projected on the MIRO y-axis (-360 to +360 deg with positive angles measured counterclockwise from the y-axis towards the negative x-axis).
BS_Z_ANG: Angle between MIRO boresight and the spacecraft to comet-center line (0 to 90 degrees).
DIST: Distance between the spacecraft and comet center (km).
EMI_ANG: Emission angle (0 to 90 deg): Angle between surface normal and MIRO boresight. Set to-NaN when FOUND_INTERSECTION=0.
FOUND_INTERSECTION: Set to 1 when MIRO boresight intercepts shape model. Otherwise set to 0.
LOCAL_SOLHA: Solar hour angle (0 to 24). Angle between surface normal at boresight location and the Sun measured in hours. 0 is midnight and 12 is Noon. Set to NaN if FOUND_INTERSECTION=0.
PHASE_ANG: Angle between Sun and spacecraft as measured at the comet center (-180 to 180 degrees; negative values represent local solar times between midnight and Noon).
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POL_ANG: Pole angle. Angle from the Rosetta y-axis to the projection of the comet spin axis on the Rosetta xy-plane (-180 to 180 degrees positive counterclockwise from the y-axis towards the negative x-axis).
RH: Distance between the comet and the Sun in AU.
SC_ANG: Angle between the Rosetta y-axis and the J2000 z-axis measured counterclockwise in the Rosetta xy-plane (-180 to 180 degrees).
SCENE_EFF_LAT: Effective latitude (-90 to 90 deg). Over the course of one comet day, the smallest angle between the surface normal and the Sun. For a given spot on the surface, effective latitude varies with season. Set to NaN when FOUND_INTERSECTION=0.
SCENE_EFF_LON: Effective east longitude (-180 to 180 deg). The angle between the prime meridian and the surface normal projected on the equatorial plane. Set to -NaN when FOUND_INTERSECTION=0.
SCENE_EFF_SOLHA: Effective solar hour angle (0 to 24 hours). The angle between the surface normal and the Sun projected on the plane of the sub-solar latitude. 0 is Midnight, 12 is Noon. Set to NaN when FOUND_INTERSECTION=0.
SCENE_LAT: Comet-centric latitude (-90 to 90 deg) of the boresight on the surface. Set to NaN when FOUND_INTERSECTION=0.
SCENE_LON: Comet-centric eastward longitude of the boresight on the surface (-180 to 180 deg). Set to NaN when FOUND_INTERSECTION=0.
SCENE_R: Distance between the comet center and the boreisght intersection with the surface. Set to NaN when FOUND_INTERSECTION=0.
SCENE_SOL_INC_ANGLE: Angle between the surface normal at the boresight location and the Sun (0 to 180 deg). Set to NaN when FOUND_INTERSECTION=0.
SSC_LAT: Comet-centric latitude of the sub-spacecraft point on the nucleus (-90 to 90 deg).
SSC_LON: Comet-centric east longitude of the sub-spacecraft point on the nucleus (-180 to 180 deg).
SSOL_LAT: Comet-centric latitude of the sub-solar point on the nucleus (-90 to 90 deg).
SSOL_LON: Comet-centric east longitude of the sub-solar point on the nucleus (-180 to 180 deg).
SUN_DEC: Position of the Sun in J2000 declination (-90 to 90 deg).
SUN_RA: Position of the Sun in J2000 Right Ascension (-180 to 180 deg).
TGT_DEC: Position of the comet in J2000 declination (-90 to 90 deg).
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TGR_RA: Position of the comet in J2000 Right Ascension (0 to 360 deg).
VLOS: Velocity of spacecraft relative to comet center projected on line-
of-sight vector in km/s.
VRAD: Velocity of spacecraft relative to comet center in km/s.
ZDEC: Declination of the spacecraft z-axis in J2000 coordinates (-90 to
90 deg).
ZRA: Right Ascension (0 to 360 deg) of the spacecraft z-axis in J2000
coordinates.
The above quantities are calculated using SPICE library functions as well as some MIRO-developed code.
9.7 ERROR BARS ON MIRO CALIBRATED SCIENCE DATA
9.7.1 INTRODUCTION
This section summarizes the error bars (uncertainty) to be associated with calibrated science data generated by MIRO Pipeline software versions 2.0 through 4.0.
Additional information on instrument characteristics relevant to this discussion
(e.g. instrument sensitivity and Allan deviation calculations) can be found in Gulkis et al. 2007 (Space Science Reviews 128, 561-597).
9.7.2 CONTINUUM DATA
The continuum brightness temperatures reported every 50 msec have an uncertainty which is dependent on the brightness of the target. In practice, there are two temperature regimes to consider. The high-temperature regime (TA>100K) occurs when looking at the nucleus (whose brightness is of the same order as that of our on-board hot and cold calibration loads). Our continuum measurements are, by design, most accurate in this regime. The low temperature regime (TA<10K) is relevant when looking at weak dust emission from the coma. Some measurements are in an intermediate regime, such as nucleus polar observations in winter. In this case, use of the low temperature regime is recommended. The submillimeter and millimeter-wavelength rms uncertainties to use with continuum data generated by MIRO Pipeline software versions 2.0 and 3.0 are given in Table 9.7-1.
Table 9.7-1: One-sigma RMS Uncertainty of MIRO Calibrated Continuum Data
Receiver Measurement Uncertainty(K) for TA >=100 K Measurement Uncertainty(K) for TA < 100 K
Submillimeter +/-1.0 +/-1.3
Millimeter +/-0.4 +/-0.5
The above uncertainties represent random errors associated with each 50 msec sample, including the random measurement errors made when observing our calibration targets. In addition to the above rms uncertainty, there are several possible systematic errors.
The largest systematic biases are thought to arise from spillover effects around the primary and secondary mirrors, discussed in detail in Section 9.9. As discussed there, we believe most millimeter and submillimeter antenna temperatures reported are about 4% lower than they should be. This bias depends on several factors, some of which are not well known or time varying, so we have not attempted to correct this in our data products. This bias affects both wavelengths similarly, so while absolute antenna temperatures need adjusting, the relative brightness of the two channels is correct.
A second potential systematic bias may affect the the calibration of the millimeter data. As
discussed in Appendix A, and summarized in Section 9.5.2 (see Eq. 4), a
design error causes the millimeter beam to sample some of the
supporting structure when looking at the cold calibration target. A
correction (the so-called w-factor) is applied, but that factor is
itself uncertain. We believe any residual errors are less than 1%.
Another potential systematic bias may arise when looking at targets
whose brightness temperature is very different than the brightness of
our calibration targets. This can be thought of as an extrapolation
error, and is the reason Table 9.7-1 accounts for two temperature
regimes. This error source can be at least partially mitigated by using
observations of empty sky. In calibration software versions 3.0 and above, these
sky measurements are used to update the calibration equation (see
Section 9.5.2). Even with this improvement, the random errors indicated
in Table 9.7-1 are still present.
A final comment about Table 9.7-1 is that it reports the uncertainty on the 50 msec continuum samples. Experimentally, it has been determined that MIRO's continuum channels are typically stable for several seconds. This allows a user to time-average continuum data and reduce rms noise levels. We estimate the uncertainty on a 5-second average to be about 3 times smaller than those reported in Table 9.7-1 in the high temperature limit, and about 1.3 times smaller in the low temperature limit. This is much less of an improvement than one would expect from averaging pure Gaussian noise (which scales as the square-root of the integration time) because of systematic errors. We note that MIRO is typically calibrated every ~30 minutes, so we cannot accurately track variations with a time scale less than that, and calibration errors are strongly correlated on that time scale. Typically, time-averaging continuum data beyond about 1 second is of limited use both because of approaching instrument stability limits and because of spacecraft motions and nucleus rotation.
9.7.3 SPECTROMETER DATA
The characteristics of MIRO spectroscopic (CTS) data are very different from those of the continuum channels. This is because of the much higher frequency resolution of the CTS, which increases the thermal (rms) noise, and because of frequency switching, which provides for a much more stable system allowing drastically longer integration times.
At full 44 kHz frequency resolution and the minimum allowed 30-second integration time, the channel-to-channel rms noise level in a spectrum is about
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16 K without frequency switching (such as when observing a calibration target). With frequency switching (all CTS science observations of Comet 67P/C-G were made with frequency switching), the rms noise level in a full-resolution spectrum is about +/- 10 K. There are variations in performance between IF bands (the bands are described in Section 9.3.2), and there are some time variations, so in general it is best to use the scatter in the spectral baseline within a given band (staying away from band edges and comet spectral features) to determine the noise level in a spectrum to be analyzed.
Since frequency switching effectively stabilizes receiver performance, the dominant uncertainty in a spectrum is thermal noise. This makes it possible to average spectra for many days (!) and reduce the noise level as the square-root of the integration time. (Of course the observing geometry and the science application rarely allow integrations that long.) Cometary lines are also typically broader than 44 kHz, allowing smoothing over frequency as well, decreasing noise by another factor of the square-root of the number of channels.
The spectrometer data are subject to the same spillover biases mentioned for the continuum data, typically ~4%. Such biases could potentially have spectral structure (i.e. may not be uniform across the entire spectrum), dependent on conditions in the coma and the location of the spacecraft. Unlike the continuum data, spectral analyses typically do not require precision to better than 10%, so most users can ignore this potential bias. A larger potential bias in the absolute calibration of the spectrometer data is in the assumed side-band ratio. As a double-sideband system, the spectra MIRO reports consist of signal from two frequency regions: one contains the targeted spectral line and the other is thought to be free of any spectral signal. The intent of MIRO's design is to deliver equal amounts of power to the spectrometer from each spectral region, and this is assumed by our spectral calibration algorithm. There is some evidence that sideband ratios may differ from unity by ~10% for the water lines and ~30% for methanol. We have no information on possible deviations from unity for the other lines. Therefore, users of the spectral data are cautioned that the absolute level of any spectral feature may be uncertain by ~20%, but this bias due to side-band ratios will not add any spectral structure across a feature.
9.8 FREQUENCY SWITCHING AND "FOLDED" SPECTRA
As mentioned in several places in this document (e.g. Section 7.1.3.4),
MIRO science spectra (other than those collected while in asteroid
mode, see Section 4.2.7) are collected using "frequency switching."
Frequency swithcing means the signal coming into MIRO is integrated for
a short time, and then a shift of 10 MHz is introduced and the signal
integrated again. One integration is then subtracted from the other,
and the difference reported as the output spectrum. This technique has
the advantage of removing many instrument artifacts, and serves as part
of the calibration and stabilization process. Because of frequency
switching, each spectral line from the comet or other science target
appears twice, once as a positive image and once as a negative,
separated by 10 MHz in the spectrometer (see Fig. 11 of Appendix A).
A square root of two improvement in signal to noise can be achieved by
combining the two images of each spectral line. This involves shifting
one of the images 10 MHz towards the other, and then subtracting it
from the other image. While really a shift and subtract operation, for
historical reasons we refer to this process as "folding" the spectra.
In MIRO Pipeline Software Version 4.0 (used to generate Level 4 Versions
1.0 and 2.0 products), the spectra that were generated by Software Version 3.0
on the "common IF frequency grid" (Level 3 Version 3.0 products; see
section 9.5.2) are folded and IF frequency is converted to a Doppler shifted
comet-centric velocity grid. The folded spectrum for each band is obtained in four steps:
1) Identify the rest frequency of the spectral line in the IF (see
Section 9.4.2), 2) Shift
the portion of the spectrum at lower frequency than the rest frequency
to frequencies 10 MHz higher, 3) Subrtact the shifted image from the
portion of the spectrum at higher frequency than the rest frequency of
the line, and 4) Divide the result by 2 (to average the two spectra)
and multiply by the direction factor given in Table 9.4-6 (this factor
of 1 or -1 depends on whether lines are effectively in the upper or
lower sideband of the receiver).
The central IF frequency for each band is given in Table
9.4-6, and Table 9.5-2 provides the channel numbers in the common
frequency grid associated with each of the 8 spectral lines.
Cometary specrtra are typically provided on a velocity scale instead of
frequency. This has several advantages for scientific analysis (such
as allowing easier comparison of the velocity distribution of different
gases). In the folded spectra, the common IF frequency grid is
transformed into a Doppler shifted comet-centric velocity grid using the standard
Doppler velocity expression:
VD = c / RFline * (Fline - F)
where VD is the Doppler velocity associated with a common grid
frequency F, RFline is the rest frequency of the line (see Table
9.4-1), c is the speed of light, and Fline is the rest frequency
of the line in the IF (to convert the sky frequency, RFline, to Fline,use expressions in Section 9.4.2 or values listed in Table 9.4-6).The velocity grid is truncated to the range of -4 km/s to 4 km/s.9.9 BEAM PATTERNS, SPILLOVER, AND ANTENNA TEMPERATURES To first order, the antenna temperatures reported when looking at the comet or other science target represent a convolution of a Gaussian main beam with the brightness distribution of the source on the sky. This approximation is good to a few percent, which is sufficient for some purposes. Recommended Gaussian beam parameters are given at the end of this section. For many applications, particularly those requiring simultaneous fitting of the mm and submm continuum data to retrieve surface properties as a function of depth, greater precision may be required. This section discusses the higher-order corrections. These involve accounting for slight mismatches in the optical coupling of components within the instrument (on the optical bench), spillover effects around the antenna (external to the spacecraft), and deviations of the true antenna pattern from an ideal Gaussian beam.We used commercially available Physical-Optics (PO) modeling packages (the CHAMP and GRASP tools made by TICRA) to analyze our optical path. We find that at both our millimeter and submillimeter wavelengths, about 2% of the received signal comes from within the instrument when looking at the calibration targets or the sky. (This 2% does not include the mismatch of the cold load with the millimeter beam, corrected for using Eq. 4 in Section 9.5.2.) Because this signal from within the instrument is always present and relatively constant, errors it creates in our instrument calibration and in the measurement of antenna temperature cancel to first order.When looking through the antenna at targets in the sky, there are spillover losses to be considered at the secondary and primary mirrors external to the spacecraft. PO modeling indicates that at both MIRO wavelengths 2% of the signal at the secondary mirror comes from spillover around the primary (the secondary mirror "sees" around the primary mirror). This spillover falls on the spacecraft body, and since the spacecraft covering is expected to be reflective at our wavelengths, it is likely that this signal is terminated on the sky above the spacecraft. A second 2% loss at both wavelengths comes from the primary mirror spilling over the secondary. This signal also terminates on the sky background. Thus, approximately 4% of the signal MIRO reports comes from broad regions of the sky.
The important conclusions regarding these first two corrections considered are:
* Under the assumption that the internal coupling to the calibration loads and the antenna are the same (which the PO modeling confirms), and to the extent that internal instrument temperatures do not change significantly on ~hour time scales (which is typically true), scattering within the optical bench has no net effect on the antenna temperatures measured by MIRO. We therefore neglect this internally-scattered emission, and believe this creates an error on the reported antenna temperatures of less than 1%. The effects of antenna spillover on the calibration of MIRO data are almost the same at the submm and mm wavelengths. This means the relative brightness measured in the two channels is not appreciably affected by these terms.
* When absolute continuum temperatures are required, spillover losses must be considered. Approximately 96% of the received signal comes from the antenna pattern (discussed below), and 4% from the sky above the spacecraft. In most situations, the 4% is from empty sky, resulting in MIRO reporting continuum antenna temperatures which are 96% of the true value. When within ~20 km of the comet, however, portions of the spillover may come from the warm nucleus. This makes the error less than 4% (but of unknown sign) when targeting the warm nucleus, and potentially larger than 4% when targeting very cold regions (e.g. polar night). Users of MIRO continuum data must assess the regime they are in and consider increasing reported antenna temperatures by 4% when far from the nucleus.
* Spillover effects on the spectral data have not been considered in detail, but are potentially complex when the spacecraft is within denser regions of the coma, the spectra being a combination of 96% of emission from where the antenna is pointed, and 4% of emission from the gas immediately surrounding the spacecraft.Figure 9.9-1: Millimeter (left) and submillimeter (right) beam patterns measured in the lab prior to launch. Beam patterns are normalized to have a peak value of 1. Note that the beams, particularly the submm, are not symmetric, with enhanced sidelobes on the +x side. This may be due to a small misalignment of the secondary mirror.We now consider MIRO's beam pattern, which describes how the signal coming from the primary mirror is distributed on the sky. The antenna temperature (neglecting the losses described above) is a convolution of this beam pattern with the source. Figure 9.9-1 shows MIRO's beam patterns as measured in the lab prior to launch. The numerical data are available from the Rosetta data archive maintained by NASA's Small Bodies Node of the Planetary Data System, and from ESA's Planetary Science Archive. (In particular, see the "Documents" section in Level 4 Version 2 data products.)Figure 9.9-2 shows azimuthally averaged antenna patterns for the lab measurements, for our Physical-Optics (PO) based model, and for an empirical fit to the other curves. In the empirical fits, the innermost Gaussian term is a fit to the lab data. The empirical fit to the far antenna pattern for both the mm and submm beams is a fit to the PO model. The submm antenna pattern has more structure than the mm, likely due to surface irregularities on the primary mirror, so the submm empirical fit includes an intermediate region which is a linear fit to the lab data. Expressions for the empirical fits are given below. Some things to note about MIRO's beam patterns are:
$* At submm wavelengths, about 3.5% of the power entering the receiver from the antenna comes from angles beyond 2.5 half-power beam widths (HPBW). Only 0.35% of the submm power comes from more than 1 degree off axis.
$* At mm wavelengths, only 0.6% of the power comes from outside 2.5 HPBW, and 0.16% comes from more than 1 degree off axis.
Users requiring precise, absolute knowledge of submm nucleus brightness temperatures in localized regions of the surface should model the observed antenna temperatures by convolving the full antenna pattern with models of the nucleus brightness distribution. In regions of strong spatial gradients in brightness (e.g. near a limb or shadow), using only the Gaussian main beam can yield errors of up to 3.5%. The Gaussian approximation for the millimeter data is better than 1%.
The empirical fits to the beam patterns shown in Fig. 9.9-2 are given by the equations below. For the most demanding applications, the full two-dimensional beam patterns shown in Fig. 9.9-1 should be used. In the expressions that follow, theta is the angle off the boresight in degrees, and G is the antenna gain in dB, normalized to a peak value of 0.
For the millimeter beam,
where
Note that the central Gaussian pattern corresponds to a beam with Full Width at Half Maximum (FWHM) of 0.3838 degrees. This is slightly smaller than the FWHM assumed when retrieving the MIRO boresight using lunar data (discussed in Section 9.6.1).
For the submillimeter beam,
where
The central Gaussian pattern has a FWHM of 0.1248 degrees.Figure 9.9-2: Azimuthally averaged millimeter (top) and submillimeter (bottom) beam patterns. The green curves labeled "lab" are for the laboratory measurements shown in Fig. 9.9-1. The black curves labeled "co-pol" are from our Physics-Optics model, and the dashed lines are empirical fits to different regions of the curves. Details of the empirical fits are given in the text. Note that the empirical fits do not attempt to match the side-lobes, but only follow the general trend of the model response.
Appendix A, MIRO Calibration
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MIRO CALIBRATION
F. PETER SCHLOERB
1. Introduction
This document reviews procedures for the calibration of MIRO data taken in the continuum channels as well as with the spectrometer. For each type of calibration, I summarize a proposed calibration algorithm for the MIRO data.
2. Calibration Basics
2.1. Basic Principles. Many basic principles of calibration have been outlined in previous descriptions of the MIRO experiment (see MIRO Experiment User Handbook version 5 section 9.2 [HBv5] and draft memos by Backus and Gulkis, [BG07] and [BG08].) For completeness, these principles are summarized here.
Calibration of MIRO is accomplished by having the receiver observe two targets at known temperatures. One target will be referred to as the "Hot" target, and the other target will be referred to as the "Cold" target. The Hot target is at a temperature of approximately +18 C; the Cold target is at a temperature of about -47 C.
The output signal from the receiver is digitized to produce a value, called a data number, which is proportional to the signal. The purpose of calibration is to convert these readings in data number, D, into values related to the noise power produced by the receiver. The noise power per bandwidth is usually characterized as the temperature of an equivalent resistor producing the same noise power, kT. It is traditional to simply drop Boltzman's constant from the discussion and talk about calibrating the signal to refer to a temperature scale. Observations of the Hot and Cold targets allow us to do this with MIRO.
Imagine that the receiver is placed in an isothermal, black, box at 0 degrees K. The receiver electronics will still produce some noise power even though it is not receving any external signal from the walls of the box. The noise temperature that we'd measure in this idealized case is usually called the "Receiver" or "System" temperature. We'll adopt the term "Receiver Temperature," TRX in this document.
Now suppose we place the receiver in an isothermal, black box at some .nite temperature. In this case, the receiver measures a signal from the walls of the box which adds to the noise power produced by the receiver alone. The output of the receiver will therefore be proportional to the sum of the noise power added from the box with the receiver temperature, and we may write that the data number output from the receiver, D, is:
Date: September 15, 2014.
1
F. PETER SCHLOERB
D = gTA + gTRX + Z (1) where TA is the antenna temperature, which is the added noise power received from the walls of the box in this case, g is the gain of the receiver, which is the constant of proportionality between noise power and data number, and Z corresponds to the data number that would be read out if the receiver produced no noise power. The MIRO calibration targets do not .ll the full 4. steradians seen by the receiver. However, for the submillimeter beam, the targets completely .ll the forward beam that couples to the antenna, which accounts for almost all the received power, and the target emissivity is designed to be very close to unity. So, to a good approximation, the antenna temperature seen is proportional to the black body radiation emitted by the target.
TAtarget / B.(Ttarget)
Thus, if we measure the signal from the receiver using two targets we may derive the unknown values in equation 1. Let THot and TCold be the antenna temperature due to the hot and cold loads, which may be derived from their known temperatures, then
DHot = gTHot + gTRX + Z
DCold = gTCold + gTRX + Z and
g = DHot THot DCold TCold (2)
I = DHot gTHot or I = DCold gTCold (3)
where I is the value of D corresponding to zero input power to the receiver.
I = gTRX + Z We can calibrate a third signal, observed through the antenna, with the observed data number value DA in terms of antenna temperature:
THot TCold
TA =(DA I)
DHot DCold DA I
TA = (4)
g
MIRO CALIBRATION
2.2. Some Practical Points for MIRO Calibration.
2.2.1. Planck Function. The input power to the receiver is proportional to the thermal emission from the source, seen through the antenna, or the calibration target. For the calibration targets, as noted previously, the emission is given by the Planck Function. For MIRO, and for other remote sensing applications, it is traditional to represent the Planck Function using the Rayleigh-Jeans approximation. At microwave frequencies, this is generally a very good approximation, but for millimeter and submillimeter frequencies and low temperatures that is not the case, and so we must account for di.erences.
h.
The Rayleigh-Jeans approximation is correct in the limit kT << 1and given by:
2h.3 12kT .2
B.(T )= h. .
c2 c2
e kt 1 We de.ne the Rayleigh-Jeans Brightness Temperature, TR,to be
c2 h. 1
TR = B. (T )=
2k.2 k h.
kT
e 1
For calibration purposes, the targets are assigned Rayleigh-Jeans equivalent brightness temperatures, according to their physical temperature. Note that TR is linear with the Planck Function, so calibration on this scale is equivalent to using the Planck Function directly.
Interpretation of measurements of the antenna temperature in terms of a brightness temperature of the object require a correction to be made. Brightness temperature, TB,is de.ned as the physical temperature of a blackbody which would be required to give the observed brightness, so antenna temperatures, TA, measured according to our scale based on the Rayleigh-Jeans approximation, have to be corrected. Figure 1 shows a graph of this relationship between TB and TA for the submillimeter channel and the millimeter channel frequencies. Over most of the interesting temperature range for MIRO, the di.erence is aconstanto.set, with TB for the submillimeter channel about 13K above TA and TB for the millimeter channel about 4.5K above TA. However, as can be seen in the .gure, the relationship is quite non-linear at very low temperatures.
2.2.2. Measurement Errors in Calibration. In principle, the measurement of the calibration targets should have very high signal-to-noise ratio compared to the measurement of celestial sources, and so errors in the calibration measurements themselves do not a.ect the errors on the sources. However, this is not always the case for MIRO, and so it is important to consider the e.ects of noise in the calibration measurements.
First consider the error in the determination of the quantities g and I as described by equations 2 and 3, assuming independent errors and de.ning T = THot TCold:
2 . 1 .22 . 1 .22
=+
gDHot DCold
TT
F. PETER SCHLOERB
Figure 1. Relationship between observed antenna temperature and corresponding brightness temperature. The Submm channel is shown in blue. The MM channel is shown in red. The dashed black line shows the relationship where the two temperatures are equal. The relationship between TA and TB is quite linear over most of the interesting temperature range for MIRO. At low temperatures, however, the correction is quite large. For example, the 2.7K cosmic microwave background would appear at TA =0.001K on the submillimeter channel scale and TA =0.33K on the millimeter channel scale.
2 .TCold .22 .THot .22
=+
IDHot DCold
TT One might expect that the error in the measurements DHot and DCold themselves depends only on the Receiver Temperature, TRX. In this case, given values for receiver temperature and bandwidth of MIRO and assuming that the errors follow the radiometer equation, one would expect very small errors in the measurement of g and I, as summarized in Table 1. However, gain variations in the continuum receiver measurements on time scales of the 30s switch time between Hot and Cold and during the interval between calibrations lead to errors in the quantities g and I corresponding to about 10 times the values expected from the radiometer equation. The situation is much worse for the so-called "bad bands" in the MIRO spectrometer.
Now, referring to equation 4, we may write an expression for the error in TA in terms of the error in determination of the data number (DA)and the errors in derivation of the gain (g)and intercept (I)from calibration measurements.
2 . DA .22. g .2 . I .2
=+ TA + (5)
TA
g gg
MIRO CALIBRATION
Table 1. Calibration Errors Expected from Radiometer Equation
Parameter MM SubMM CTS
TRX 2000 K 4000 K 4000K
Bandwidth 500 MHz 1000 MHz 44 kHz
Integration Time 30 s 30 s 30 s
T RMS 0.02 0.02 3.48
g (percent) g 0.04 0.05 8.21
I (K) g 0.14 0.19 29.22
where in this equation the .rst error term corresponds to an error in the measurement of the data number associated with this observation, the second term is the contribution made by error in the measurement of the gain g and the third term is the contribution made in the measurement of the intercept parameter I.
2.2.3. Cold Target Measurements in Millimeter Channel. The beam from the millimeter-wave receiver is too large to be properly matched to the opening to the cold target, and so only a portion of the beam actually hits the cold target. The remaining part of the beam falls inside the receiver box somewhere, and so this must be accounted for in the calibration.
A practical method to account for this was presented in [BG07]. The signal from the cold target for the millimeter-wave receiver is assumed to be a combination of emission from the cold target and from the interior of the receiver box at the temperature of the receiver optical bench. Thus,
TMM
Cold = wTCold +(1 w)TOpticalBench Assuming that the receiver is linear, the factor w in the above can be estimated by observing blank sky, which is expected to have TA =0.33K. Analysis of a period of data obtained during the Deep Impact observations in [BG07] suggested w was approximately 0.91. My own estimate from the same dataset gave 0.915. More recent measurements (see description in next section) suggest that this may have changed since 2005.
2.2.4. Receiver Linearity. The receiver linearity was tested pre.ight, as reported in [BG07]. Additional tests were carried out in .ight during the Deep Impact dataset. [BG07] reports that the millimeter receiver channel may su.er from some compression, although the Deep Impact measurements suggest that this may not be a very serious problem compared to the problem of not knowing the Cold target brightness to high accuracy. The submillimeter measurements show that the receiver is quite linear.
Linearity checks can be made regularly through observations of the blank sky. The Hot-Cold calibration is always followed by a measurement of the Sky position, so on blank sky we should always get a value close to the expected value for the CMB. In practice, MIRO observations of blank sky are close to the correct values, but often in error by small amounts of 1-3 K as illustrated in Figure 2. These o.sets could be the result of a change in linearity of the receivers, or in the case of the millimeter channel, they could arise if the w factor
F. PETER SCHLOERB
has changed with time. In either case, the small o.set from 0 does not represent a major calibration problem for continuum measurements of the nucleus.
Figure 2. Sky Antenna Temperatures derived during calibration observations obtained during days 161-168 of 2014. The left hand .gure shows the antenna temperature derived for the millimeter channel; the black line shows the expected value for a 3K blackbody (0.47K). The millimeter calibration uses the nominal w factor of 0.915 and the o.set from this expected value could indicate that the w factor has increased to 0.925 or so. The right hand .gure shows the results for the submillimeter channel. In this case, data were obtained during frequency switching, and separate calibrations were made for the two frequency switch states (LO 0 is red; LO 1 is blue). The black line shows the expected level for a 3K blackbody (0 K).
2.2.5. Impact of Instrument Housekeeping Data System. The readout of the MIRO receivers is signi.cantly a.ected by the electronics for the housekeeping data. When the housekeeping system is on, the data number readout is depressed, as shown in Figure 3, and this can have an e.ect on the receiver calibrations. For example, observations of the sky during the Deep Impact data set showed a signi.cant variation in the calibrated signals, especially in the millimeter channel. This is now understood to be the result of the regular housekeeping cycle, which was on for 11.2 sec and o. for 56 sec, beating with the quasi-regular cycle of calibration observations. Consequently, the current approach with MIRO is to leave the housekeeping system on all the time so that all observations of the calibraton targets su.er the same systematic o.sets from the housekeeping system.
3. Calibration of Continuum Data
Calibration of the MIRO continuum data follows the basic approach outlined above. Measurements of the Hot and Cold targets are obtained every half-hour, along with a third measurement of whatever is in the antenna beam at the time. Ideally, one would use these regular measurements to track real variations in the receiver gain and intercept values. However, observations show that the individual measurements of gain and intercept have limited accuracy.
MIRO CALIBRATION
Figure 3. On-sky observations phased in relation to the housekeeping data duty cycle. Left hand .gure is from the deep impact data, where the housekeeping data was on for 11.2 seconds and then o. for 56.0 seconds. The time period when the system was on su.ered a 2 datanumber depression, corresponding to about 0.4 K in antenna temperature. The right hand plot shows a similar plot for data obtained in 2014. In this case the housekeeping system is always on, so the relevant duty cycle is 11.2 sec. There is a small drop in signal during a portion of the 11.2 sec cycle.
3.1. Dual Continuum Mode Example. During the approach to comet C-G, MIRO performed a number of trial checkout measurements. These serve as an opportunity to check the continuum system in its di.erent modes and test calibration methods on the blank sky. Figure 4 shows the gain and intercept derived during dual continuum mode observations. It is apparent that there are drifts in these values, especially during the initial times when the receiver was warming up. It is therefore important to track these changes, but it is also clear that the determination of the gain and intercept have a scatter which is fairly large compared to the overall trends observed. The scatter is a consequence of measurement errors, most likely due to short timescale variations in receiver total power, and direct use of these measurements leads to artifacts in the calibrated data.
In order to illustrate the in.uence of calibration measurement errors, we present, in Figure 5, the calibrated Sky temperatures assuming two di.erent methods for applying the calibration. In the left hand .gure, we linearly interpolate the calibration measurements to calibrate the Sky data. In this case, the noise in the calibration measurements introduces an artifact into the Sky measurements. In the right hand .gure, the calibration is done by averaging the four calibration measurements that surround a block of data. In this case, the averaging process improves the determination of the gain and intercept and does not introduce artifacts unless the gain and intercept really vary over the 1.5 hour time interval represented in the four calibration measurements.
3.2. Dual CTS Mode Example. In Dual CTS Mode, the spectrometer is active and the LO is frequency switching. The frequency switch causes a change in the signal observed in the Submm continuum channel, as shown in Figure 6. The change in the signal suggests that, for the Submm channel, we must calibrate the gain and intercept separately for the two LO states.
F. PETER SCHLOERB
Figure 4. Measurements of the Submm channel gain and intercept obtained in Dual Continuum Mode during days 159-160 of 2014. Gain measurements are shown in the left hand .gure, where we see that the scatter of individual measurements is much larger than any apparent drift after the receiver has warmed up. Intercept measurements are shown in the right hand .gure. Here the scatter is large, but a noticable drift occurs during the time of the observations. The gain changes by less than 1%, but the intercept drifts by 20 data numbers, corresponding to 12 K.
Figure 5. Results of applying di.erent calibration methods on the MIRO Submm channel data obtained in Dual Continuum Mode during days 159-160 of 2014. The left hand .gure shows the result of applying the nominal calibration technique, where a linear interpolation is made of calibration results. It is pretty clear that systematic errors are introduced by this process, though the levels are only at the level of a few K. The right hand .gure shows the result of calibrating by using the average of four calibrations that bracket the data in time.
Figure 7 shows the gain and intercept values derived from calibration observations made in Dual CTS mode. The red points show the results for LO=0 and the blue points show results for LO=1. The measurements show that there is no statistically signi.cant di.erence in the gain derived for the two LO states. The main di.erence in the receiver calibration is an o.set in the intercept value, which is the cause of the square wave in Figure 6.
The calibration observations in Figure 7 show a small drift in the gain of the receiver with time and a larger drift in the intercept value. In addition, we note, as in the case of
MIRO CALIBRATION
Figure 6. 200s of uncalibrated, on-sky, data obtained in Dual CTS Mode with the Submm receiver. Individual samples are 1 s averages of the continuum data. The apparent square wave results from the frequency switching of the receiver.
Figure 7. Measurements of gain (left) and intercept (right) made with the Submm receiver during Dual CTS calibration observations. The gain and intercept are determined separately for the two LO positions in frequency switched data. Red points indicate LO=0 and blue points are for LO=1. The total drift in the gain is less than 1%, but the drift in intercept is 40 data numbers, corresponding to 24 degrees of antenna temperature.
the Dual Channel Mode data, that there is a signi.cant scatter in the measurements that is large compared to the real drifts in these quantities. In order to remove the e.ect of this scatter, and yet still account for the drift, we may employ a smoothing function to average calibrations.
F. PETER SCHLOERB
Ihavebeen experimentingwith asecond-order, least squares .lter to.t thecalibration data. To do this, we use 16 calibration observations, corresponding to an 8-hour window in time, and .t a second-order curve through the gain and intercepts that are derived individually. The gain and intercept values applied to the data then follow the second-order curves. The averaging of 8 hours of data lowers the e.ect of individual calibration errors, but has the obvious drawback of limiting the response time of the calibration to real changes that might occur on shorter time scales.
Figure 8 shows the result of a running, second order, least squares .lter .t to 16 calibration points (8 hours of calibration data). The .lter does a reasonable job of tracking the changes in the receiver. The resulting residuals to the .t are 0.0095 DN/K for the RMS gain residual and 2.4 DN for the RMS intercept residual, which corresponds to 1.4 K RMS. Both of these values are larger than expected for measurement errors alone by a factor of about 2.3. This can be accounted for with relatively small (0.5 DN) random drifts in the reciever during the calibration cycle.
Figure 8. Measurements of gain (left) and intercept (right) .t with a running 16-point, second order least squares .lter. The error bars on the points represent the expected error in the value based on errors in the measurement of Hot and Cold alone.
Figure 9 shows the results of three di.erent approaches to calibrating data. Each point in the .gures represents a half-hour average of the continuum signal calibrated using a di.erent method. The .rst approach, in the left panel follows the nominal MIRO method using the calibration measurements which bracket a half-hour of observation. The second method uses each calibration observation to derive a gain and intercept. These values are then smoothed with a 16-point, second order, least squares .lter before applying values to the data points. Finally, the third method, in the right panel, is based on the observation that the gain varies slowly and by a relatively small amount. Therefore, we can model the slow drift and then use the individual calibration measurements to derive the intercept value. The gain model and intercept are then used with the 16-point least squares .lter to calibrate the data.
It is pretty clear that the third method produces the smallest scatter of the measurements, with a standard deviation about 1/3 of the nominal approach. The mean value in all cases is consistent with a value of about 0.85. This small o.set from 0 might be attributed to a small non-linearity in the receiver output with input power. However, smoothing the calibration
MIRO CALIBRATION
Figure 9. Examples of calibration methods applied to the Dual CTS data from day 161-168. The left hand plot shows the data calibrated with adjacent calibration observations. The center .gure shows the result of calibration using the 16-point, second order, least squares .lter applied to measurements of the gain and intercept derived from each calibration observation. The right .gure shows the result of a di.erent approach, where the gain is modelled by asimplelineardriftandtheinterceptisdeterminedby.ttingthecalibration observations assuming the gain in the model. The 16-point .lter is used to make an average of the intercept values and track their long term drifts.
measurements over 8 hours with the 16-point .lter leads to systematic drifts in the calibrated data when the instrument changes over shorter time scales. Note, for example, the feature at day 167.4 in the right hand panel of Figure 9 whiich occurs at the time of a sharp variation in the intercept values determined in the calibration observations.
3.3. Summary of MIRO Continuum Calibration Points. The gain and intercept values measured by the MIRO receivers during their calibration cycles do vary with changing conditions in the instrument. It is important to be able to follow these variations to properly calibrate the instrument data.
Calibration measurements have an intrinsic error which is larger than would have been anticipated from the radiometer equation alone. Errors in the measurement of gain and intercept increase the error in the measurements, according to Equation 5, and so it is useful to average calibration measurements to lower the errors. One must be careful to adopt an averaging strategy that does not eliminate the ability to follow real changes in the instrument, but fortunately on time scales of a few calibrations, it is possible to average the measurements without seriously compromising the ability to follow real changes.
Gain measurements show that the change in gain with time is typically slow, with drifts of less than a percent over days. On the other hand, changes in the intercept value are much more noticable, amounting to many degrees, and apparently drifts in the receiver readout are more important than changes in the gain. For this reason, I favor an approach which averages more measurements, over longer time scales, to determine gain and then uses the derived gain to estimate the intercept, allowing shorter time scale variations to occur.
F. PETER SCHLOERB
3.4. Proposed Algorithm for Continuum Calibration.
(1)
Use calibration observations to estimate the gain and intercept for a set of data. For the submillimeter data, it is necessary to estimate the gain and intercept separately for the two LO states of the frequency switch.
(2)
Based on the gain measurements with time, it may be possible to model the gain for the data set with a single constant or a simple slope. A single value of the gain is adequate for both LO states. Adopt a model for the gain variation and use the calibration data to solve for the intercept values.
(3)
For a half-hour set of observations, select a time window for averaging the intercept data. Two averaging approaches might be used: (1) a simple average of a set of measurements for a number of observations around the half-hour set of data; or
(2) a running least-squares .lter, which would better track time variations in the calibration.
4. Calibration of Frequency Switched Data
To make a frequency switched spectrum, the .rst LO of MIRO's submm receiver is switched alternately by -5 MHz and +5 MHz and the di.erence between the spectra in these two states is recorded for all spectral channels. Any spectral lines change IF frequency when the LO is shifted, and so in a di.erence between these two states, a real line will appear as a positive and negative feature in the di.erence spectrum.
4.1. Observations. Following our previous descriptions, we may write that the Data Number, D, recorded for a particular channel (or bin number) of the spectrometer, n, should be:
Dn = gnTn + gnTRX + Zn (6)
where gn is the gain of the receiver at channel n, Tn is the source antenna temperature at channel n, TRX is the receiver temperature (assumed here to be constant over the band for simplicity), and Zn is the Data Number corresponding to zero input power (from source or system) for the spectrometer at channel n.
MIRO calibrates spectral line data by observing Hot and Cold calibration targets in total power with the spectrometer. (It is worth remembering, at this point, that the calibration signals from the targets are continuum signals which are observed in both of the receiver sidebands, whereas the line emission we seek to measure comes from only one of the sidebands. Thus, when it is time to consider the strengths of spectral lines, we will have to consider the relative gain of the particular receiver sideband that the line appears in.) We may follow equation 1 to write down the expected data number for channel n when observing the Hot and Cold loads:
= gnTHot + gnTRX + Zn
DnHot
DnCold = gnTCold + gnTRX + Zn
MIRO CALIBRATION
Given measurements of D and knowledge of the two signal levels, THot and TCold,we may derive gain g and intercept I as in the continuum case. The gain for channel n is:
DnHot DnCold
gn = (7)THot TCold The intercept, In corresponding to the Data Number that would be observed with no input signal above the background provided by the system temperature, corresponds to:
In = gnTRX + Zn
and we can estimate the intercept value from the calibration observations:
In = DnHot gnTHot or In = DnCold gnTCold (8)
4.2. Calibrating a Spectrum. Lets consider a simple source with a spectral line, with signal TL which varies with channel number, above a continuum, TC, which does not vary with channel. Figure 10 illustrates the situation. For this model it is important to understand that the line signal, TL, enters the receiver in one sideband (Single Sideband or SSB), while the continuum signal will enter both sidebands (Double Sideband or DSB). Our calibration signals are all continuum signals, so our antenna temperature scale is DSB and we must make a correction for the SSB nature of the spectral line emission when the data are .nally calibrated. Formally this would depend on the sideband gain, gSB, for the sideband containing the spectral line. For equal gain between the two sidebands, gSB =0.5.
Figure 10. Simple model for spectral line with a continuum. TL is the strength of the line above the continuum level TC.
The Data Number for channel n in our model would be expected to be:
Dn = gSBgnTLn + gnTC + In
However, for frequency switched data, we must allow the possibility that the gain and intercept may be di.erent for the two settings of the .rst LO. Previous MIRO documents identify the -5 MHz LO shift as the LO=0 state and the +5MHz LO shift as the LO=1 state, so to be consistent with this, we'll adopt gn 0 and In 0 as the gain and intercept for the -5 MHz LO
F. PETER SCHLOERB
shift and gn 1 and In 1 for the +5 MHz LO shift. Thus, the LO 0 (-5 MHz) and LO 1 (+5 MHz) spectra may be written individually:
D00T 00
n = gSBgnLn + gnTC + In 0 D11T 11TC + I1
= gSBg + g
nLn nn
Taking the di.erence between these two spectra will give:
D0 D1
=
Dn nn
00 11
Dn =(gSBgnTL0 n + gnTC + In0)(gSBgnTL1 n + gnTC + In1)
01 01
Dn = gSB(gnT 0 gnT 1 )+(gn gn)TC +(In 0 In1) (9)
Ln Ln
Looking at equation 9 we see that the line information we seek is in the .rst term of the RHS of the equation. The additional terms are expected to be zero or close to zero, and in any case they simply represent o.sets of the spectral baseline. This being the case, we may .t a baseline to the spectrum outside of the regions where there is line emission and remove any small o.sets that persist. If we follow such a procedure, then the di.erenced spectrum with baseline removed is D0, where
D0 0T 01T 1
= g ) (10)
n gSB(gnLn nLn
Figure 11. Top panel shows spectrum in spectrometer with PLUS o.set; Middle panel shows spectrum with MINUS o.set; Bottom panel shows di.erence spectrum obtained by frequency switching.
Figure 11 illustrates the spectra observed for our simple model with frequency shifts and the resulting di.erence. Consider channels 75 and 25 in our di.erence spectrum, where we .nd the peaks of the line emission. In the case of channel 75, TL0 75 =1 since this is the peak of the line for the PLUS LO shift (as seen in top panel of Figure 11), and TL1 75 =0 since this channel is far from the line for the MINUS LO shift. (For channel 25 we have the opposite
MIRO CALIBRATION
situation.) Therefore, the counts observed above the baseline level at the peak of the line signal (at channel 75) is
D0 0
=
75 gSBg75TL0 75 So in this case, we can estimate T 0 from the measured value of D0 , the sideband gain,
L75 75gSB, and the receiver gain g0
75.
D0
T 0 75
=
L75 0
gSBg75
In a similar fashion we can estimate the line peak from the feature at channel 25 in our example.
D0
T 1 25
=
L25 1
gSBg25
4.3. Folding the Spectrum. From the above, it is obvious that we get two estimates of the strength of the line in our frequency switched spectrum. Therefore, we can average these to get an improved estimate. This is commonly done with frequency switched data in a procedure known as folding the spectrum. In this procedure, the positive and negative peaks are aligned and averaged to improve the signal-to-noise ratio.
In this example case, the frequency of the line with LO shift 0 corresponds to channel 75 and the frequency of the line with LO shift 1 occurs in channel 25. We would, therefore, create aspectrum shiftedby50 channels anddi.erence it with the original spectrum. Considering the peak of the line, this would align channels 75 and 25 and and allow an estimate of the Line Temperature, TL, by taking the average:
D0 D0 TL = 01
1( 75 25)
gSB (g75 + g25) In the above equation, we see that the gain factor needed to calibrate the folded data combines the gain measured on LO=0 and LO=1. For MIRO, the gain is pretty .at over
00 11
the band, so that all gn = gand all gn = gthen the folded spectrum may be calibrated with the average of g0 and g1
g0 + g1 g =
2
1 1( D0 D0 )
75 25
TL =
gSB g 2 and we see that we have the folded spectrum, taken by averaging the two lines, divided by the average gain, and including the correction for the sideband gain of the system.
F. PETER SCHLOERB
4.4. Special Features of MIRO Calibration.
4.4.1. ADC O.sets. The CTS channels are read out sequentially by a group of four analog to digital converters. Each converter has a di.erent "zero" and so the raw spectra have a consistent four-channel pattern. Figure 12 shows a set of spectra from the water channel, obtained on May 9, 2014, displayed as a waterfall plot. The right two panels show the raw Hot and Cold target spectra and the pattern of vertical lines that is apparent is the result of the ADC o.sets. The use of di.ent ADC's means that the intercept parameter in our calibration scheme di.ers from channel to channel. On the other hand, the gain of the receiver is quite constant and shows no pattern in the left hand image presentation of the gain.
Figure 12. Calibration spectra in the water channel obtained on May 9, 2014. The left hand .gure shows the receiver gain derived from each channel from the Hot and Cold spectra shown to the right. The vertical lines in the Hot and Cold spectra are the result of the ADC o.sets described in the text.
In developing a calibration scheme for the spectrometer, it is important to take the large o.sets between channels into account and derive the gain for each channel before any other manipulations or resampling of the spectrum.
4.4.2. The "Bad Bands". Bands 1 (H217O), Band 4 (CO)and Band6 (NH3; CH3OH)are signi.cantly less stable than the other spectrometer bands. The three bands share a common ampli.er which appears to have poor stability. The result is that the receiver total power readout can change by an amount which is comparable to the Hot-Cold calibration signal itself. Consequently, every individual calibration measurement obtained should be viewed with suspicion.
Figure 13 shows the waterfall plots for Band 1 during the same time period shown in Figure 12. There are large enough variations in the total power during a calibration observation that it is possible to get large apparent changes in the gain, including negative values.
MIRO CALIBRATION
Figure 13. Calibration spectra in the H217O channel (Band 1) obtained on May 9, 2014. The left hand .gure shows the receiver gain derived from each channel from the Hot and Cold spectra shown to the right. In contrast to the water line channel, shown in Figure 12, this is one of the so-called "Bad Bands", and it is apparent that there are large changes in the total power Hot/Cold measurements which lead to correspondingly large changes in the derived gain.
What can be done to calibrate the "bad bands"? The variations in the total power signal are not large on the scale of the total power due to the receiver alone. However, because the calibration signal is only 1.5% of the receiver temperature, it does not take a very large percentage change in the total power to make a big change in the derived gain. The key is to use multiple observations of the total power made during calibration measurements during a set of data to measure the receiver gain. This necessarily means that the gain in a "bad band" is a long term average over many hours. However, observations suggest that the typical gain is not strongly variable with time.
Figure 14 shows examples of the measured gain as a function of time for the June 6, 2014 data set. In these .gures, a median spectrum has been created by taking all data for each channel in the band and .nding the median value. We then take the mean of the di.erence between the total power values observed in each channel and the median value and plot the result for each calibration observation.
Band 0, the water line band, shows that after a period of warm-up , the total power measured varies by only a small amount for each calibration observation. On the other hand, the right hand .gure, for "bad band" Band 1, shows quite a bit more variability, up to 2%. Looking at the trends, however, it seems possible to create a long term average of the Hot/Cold total power measurements that would allow an improved estimate of the gain.
4.4.3. Di.erence in Gain between LO States. Measurements of the gains in LO=0 and LO=1 demonstrate that there is no signi.cant di.erence between the two. Figure 15 shows measurements from the individual calibrations during the June 6, 2014 data set shown in Figure 14.
F. PETER SCHLOERB
Figure 14. Measurements of the mean of the Hot and Cold spectra with respect to a spectrum formed by taking the median for each channel in the data set. (Results for LO=0 and LO=1 are merged since there is no statistical di.erence between them.) The Hot results are o.set by 5% from the Cold results for this display, though we note that the real di.erence between the two is only about 1.5% of the total power. The left hand .gure shows the result for the water line band (Band 0), which is one of the "good bands". The top panel shows the total power measurements, and the lower panel shows the derived gain measurements. The right hand .gure shows the same plot for a "bad band", Band 1 which is the H217O band. Note that there is a di.erence scale for the gain plots for the two bands.
The fact that there is no di.erence in gain between the LO states is consistent with the same observation in the continuum calibration measurements. The main di.erence between the LO states appears to be a shift in the total power, rather than a tru change in the receiver gain.
Figure 15. Measurements of the di.erence in the receiver gain derived for the LO=0 and LO=1 state for Band 0 and Band 1, a "bad band". There is no systematic di.erence in the derived gains for these bands. Note that the scatter in the "bad band" number 1 is larger than for the good Band 0.
4.4.4. Average Gain Across Spectrum. The receiver gain measured across the full bandwidth of each receiver band in the spectrometer does not appear to have a large variation. In
MIRO CALIBRATION
Figure 16. Measurements of the receiver gain across the bandwidth of the receiver band. The black lines show the median value of the gain and are spaced by 100% for each individual observation. The left hand .gure shows the water band, Band 0; the right hand .gure shows the result for the "bad band", Band 1.
Figure 16 we show the spectrum of the gain for Band 0 and Band 1 in the June 6 2014 data set.
4.5. Proposed Calibration Algorithm. We seek an algorithm that can account for the observed features of the spectrometer outlined in the preceeding section. As is the case with the continuum calibration, an important part of the process is to average calibration measurements in order to account for variations in the total power signal which occur on the time scale of the calibration measurement. The problem is particularly acute for the "bad bands" of the spectrometer.
Iwould recommend calibratingdatafor each ofthespectrometer bandsseparately since we may wish to use di.erent parameters for the calibration procedure for di.erent bands.
(1)
De.ne a window for determining the receiver gain. Nominally, the window should cover a few hours to be most e.ective, though we do wish to have the window short enough to allow for real variations. For a particular half-hour of observations, a simple approach would be to include all calibration observations within a particular time interval centered on that half-hour.
(2)
Within the window, construct an "average" spectrum for the Hot and Cold target observations in each of the two LO states. Use of a median value for each channel might be preferred since bad outliers would be eliminated.
(3)
Compute the gain in each channel from Hot and Cold average (or median) spectra.
(4)
Average the gain over the full bandwidth of the particular band being calibrated for each LO setting.
(5)
In general, we expect the average gain derived in this way to be the same for the two LO's, and folding spectra will e.ectively make this the case. Therefore, I would also average the gains for the LO settings to derive a single gain value for each band.
F. PETER SCHLOERB
5. References
[BG07] Backus, C., and Gulkis, S. (2007) Analysis of Continuum Gain Calibration and Linearity Draft Memorandum; last updated 07/16/2009.
[BG08] Backus, C., and Gulkis, S. (2008) MIRO Chirp Transform Spectrometer Calibration Draft Memorandum; last updated 03/03/2009.
[HBv5] Frerking, M., Gulkis, S., Kamp, L., Koch, T., Nowicki, R. (2013) MIRO Experiment User Manual version 5 dated 09/25/2013.