Index of /holdings/ro-x-gia-2-ear2-earthswingby2-v1.0

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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