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PDS_VERSION_ID = PDS3
LABEL_REVISION_NOTE = "V1.0"
RECORD_TYPE = STREAM
OBJECT = TEXT
NOTE = "Rosetta GIADA data during Earth swing-by 2 phase"
PUBLICATION_DATE = 2011-03-08
END_OBJECT = TEXT
END
Rosetta GIADA data during Earth swing-by 2 phase
1. Introduction
This volume contains Experiment Data acquired by GIADA during
'Earth swing-by 2' phase. More in detail it refers to the data provided during
the following in-flight tests:
'Active Payload Checkout n. 6' (PC6) held on 15/16/17-09-2007 and 24-09-2007;
'Passive Payload Checkout n. 7' (PC7) held on 06/07-01-2008 and 17-01-2008.
It also contains documentation which describes the GIADA experiment.
The 'Active Payload Checkout n. 6' (PC6) test is the second of five Active
Payload checkouts to be carried out before any major activity during the
Rosetta Cruise phase. GIADA PC6 consists of two phases. The first phase is a
passive test (GD01) similar to the previous Passive Payload Checkouts n. 0-3
and 5, the second phase is an active test (GD02 and GD03). The passive test
(GD01) was executed on 15-16 September 2007 by switching on Main and
Redundant I/Fs in sequence and executing similar procedures for the two cases.
The active test was executed on 17 September 2007 (GD02) and on 24 September
2007 (GD03) in order to test and validate respectively some new settings
by patching Configuration Table in RAM and Context File in NVRAM.
The 'Passive Payload Checkout n. 7' (PC7) test is one of routine checkouts
performed during the Rosetta Cruise phase. GIADA PC7 was executed on
06-07 January 2008 by switching on Main and Redundant I/Fs in sequence and
executing similar procedures for the two cases. Unfortunately during the test
on Redundant I/F, an emergency procedure was triggered due to a thermal
contingency and GIADA was switched off but left with the Cover open. For this
reason a further timeline (RECOVERY) was prepared and performed on 17 January
2008 in order to check the status of all subsystems and finally to close
the Cover.
For both Payload Checkouts a sequence of threshold and gain setting changes
was applied in order to test the sensitivity of different sensors.
MBS heating was also performed.
We recall that starting with PC2, some new FCPs have been used during the
passive test, together with other FCPs already validated in the previous
GIADA Commissioning phases. No new command was added/modified since then,
so the timelines used for Main and Red I/F in PC06_GD01 and PC07_GD01 are
similar to the timelines used during PC2, PC4 and PC5.
Data reported in the present volume are at CODMAC level = 2; therefore they
are essentially in the form of physical quantities with units, when
appropriate (e.g., voltages in Volts, temperature in Celsius deg), but not
converted to yield data in scientific units (CODMAC level = 3).
The data set organisation conforms to the Planetary Data System (PDS)
Standards, Version 3.0, Jet Propulsion Laboratory (JPL) document JPL D-7669,
according to the structure agreed with ESA and described in
RO_GIA_OACUPA_IF_011_I3 (reported in DOCUMENTation dir).
A general description of GIADA instrument is in RO_GIA_OACUPA_IF_011_I3.
See also RO_GIA_OACUPA_RP_106_1 and RO_GIA_OACUPA_RP_107_1
(reported in DOCUMENTation dir) for evaluations on GIADA behaviour during
this mission phase.
2. File Formats
See Sections 3 and 4 of RO_GIA_OACUPA_IF_011_I3 (reported in DOCUMENTation
dir).
3. Data Set Contents
The files on this volume are organized in a directory tree as described in
RO_GIA_OACUPA_IF_011_I3 (reported in DOCUMENTation dir).
We recall here that GIADA is formed by 3 detection devices: GDS (Grain
Detection System), IS (Impact Sensor) and MBS (Micro Balance Sensors),
guided and controlled by ME (Main Electronics).
We recall that GIADA may operate in four different operative modes. These
modes can be selected autonomously by the S/C control system, as well as by
means of ground TCs. Different operational modes correspond to different
active subsystems, so allowing to measure different quantities, as it follows:
Mode Name Active subsystems (nominal) Measured quantities
SAFE ME None
NORMAL ME, GDS, IS, 5 MBSs Dust flux and fluence
Grain Scattering properties
Momentum of single grains
Velocity of grains
Mass of single grains
FLUX ME, 5 MBSs Dust flux and fluence
COVER ME, Cover or Frangibolt None
In each Mode different sensors may also be switched ON/OFF separately by
proper TC. While scientific data are acquired in NORMAL or FLUX Modes only,
Housekeeping data are acquired in all Modes.
We recall that GIADA is a "dust event driven" experiment, so that no
scientific data are collected until arrival to the comet. Therefore, during
Rosetta Cruise Phase no scientific event is recorded. Actually, some
"scientific events" are recorded by GDS and IS, but they are not real dust
events and must be neglected.
In-flight calibration and housekeeping data are collected and reported in
the data set. They are relevant to follow the behaviour and health status of
the GIADA experiment and must be used in comparison with data obtained during
on ground and other in-flight tests (see other relevant data sets).
Under the DATA sub-directory, different sub-sub-directories are present of
four main classes.
First class: directories containing actual scientific data related to dust
monitoring. They are labelled with the acronym of the GIADA sub-system.
GDS+IS, GDS and IS directories contain "scientific data" related to "single
grain detections" by: GDS_IS (when a grain is detected by GDS and IS in
sequence: this is the "nominal" detection of a grain by GIADA); GDS (when a
grain is detected by GDS, but the grain momentum is too small to activate the
detection by the IS or it does not reach at all the IS); IS (when a grain is
detected by the IS, but it was not able, e.g. too small, to activate the
optical detection by GDS). If no grain is detected by the relevant sub-system
the corresponding directory is not present in the data set.
MBS directory contains the periodic reading of each of the five microbalances.
Second class: directories containing data acquired for periodic calibration
of sub-systems. They are labelled with the acronym of the GIADA sub-system
followed by _CAL.
Third class: directories containing housekeeping (HK) and instrument status
data for instrument health control and verification of behaviour in function
of issued commanding sequences.
HK_DATA contains HK data acquired periodically, independently on scientific
operation of GIADA. These data guarantee a control of GIADA. It also contains
a record of GIADA status in terms of operative parameters that are set at the
switch on and can be modified by Telecommand during operation.
HK_SCI contains HK data recorded contextually to acquisition of "scientific
events". These data are useful, for example, to check behaviour of scientific
signals with operative conditions (e.g. temperature) and instrument status
(e.g.: laser illumination) at the time of event detection.
Fourth class:
MBS_HEAT contains data acquired when MBS's are heated (this operation is
not automatic and is triggered by a suitable Telecommand). This procedure can
be activated to try to remove deposited (mainly volatile) material from the
sensors in case they should become saturated. Practically, the run of this
process is also useful to analyse (periodically) the behaviour of the
frequency vs. temperature for each MBS.
Under each sub-sub-directory just described, the data are organised in
a further lower level according to the date of acquisition and to the kind
of test performed on GIADA.
Data reported in CALIB sub-dir are of two classes:
ENG_CAL: contains data (for Main and Red Interface) for polynomial laws to
convert digital numbers (ADC counts) into engineering data with units. Both
these data formats are reported in the different data files.
SCI_CAL: contains data for transformation of engineering data into
scientifically relevant data. These data are not present in the volume.
Further details about the data content are reported in the *INFO.TXT files
present in each sub-dir.
4.Data Quality
At each GIADA switch ON, a careful data analysis is performed to validate
data quality with respect to previous on-ground and in-flight switch-on. This
check is based on comparison of GIADA housekeeping data and analysis of
operation conditions.
The quality of GIADA data is identified based on this analysis. The approach
is different for data sets at CODMAC 2 or 3 levels and for housekeeping or
scientific data.
For data at CODMAC 2 level, the data quality convention is as shown below:
ID => DESC => Comment
1 => GOOD => All HK and SCI data in the TAB file are good
2 => SPURIOUS EVENTS PRESENT => When only some spurious data are present in
the TAB
3 => BAD => A large amount of spurious data is present in the TAB
N/A=> N/A => The file contains reference information/data which are not HK or
SCI data
5.Errata and Disclaimer
A cumulative list of anomalies and errors is maintained in the file ERRATA.TXT
at the root directory of this volume, if needed.
Although considerable care has gone into making this volume, errors are both
possible and likely. Users of the data are advised to exercise the same
caution as they would when dealing with any other unknown data set.
Reports of errors or difficulties would be appreciated. Please contact one of
the persons listed herein.
5. Whom to Contact for Information
For questions concerning this data volume, data products, documentation and
GIADA in general:
Luigi Colangeli
INAF - Osservatorio Astronomico di Capodimonte
Via Moiariello n. 16
80131 Napoli (Italy)
Electronic mail address: giada@na.astro.it, colangeli@na.astro.it
Pasquale Palumbo
Universita' "Parthenope"
Via A. De Gasperi n. 5
80133 Napoli (Italy)
Electronic mail address: giada@na.astro.it, palumbo@na.astro.it