PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM LABEL_REVISION_NOTE = "Arnaud Mahieux, 2011-06-07" RELEASE_ID = "0003" REVISION_ID = "0000" PRODUCER_INSTITUTION_NAME = "SERVICE D'AERONOMIE/BELGIAN INSTITUTE FOR SPACE AERONOMY" OBJECT = DATA_SET DATA_SET_ID = "VEX-Y/V-SPICAV-3-SOIR-EXT1-V2.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "VENUS EXPRESS SKY/VENUS SPICAV 3 SOIR EXT1 V2.0" START_TIME = 2007-10-03T00:00:00.000Z STOP_TIME = 2009-05-28T23:59:59.000Z DATA_SET_RELEASE_DATE = 2011-06-07 PRODUCER_FULL_NAME = "BERTAUX/NEEFS/MAHIEUX" DATA_SET_DESC = " Data Set Overview ================= The data set contains SOIR data covering observations performed from mtp21 to mtp49. An extensive description on how to use these data can be found in the EAICD (Archive Interface Document) in the DOCUMENT directory. This set contains raw data. To this raw data set another datset corresponds and can be found under DATA_SET_ID ''VEX-Y/V-SPICAV-3-SOIR-EXT1-V2.0'' and DATA_SET_NAME ''VENUS EXPRESS SKY/VENUS SPICAV 3 SOIR EXT1 V2.0'' with calibrated data. Essential Reading ================= The following documents, located in the DOCUMENTS directory are essential for the understanding and interpretation of this data set: Name Description ---------------------------- --------------------------------------- EAICD SOIR Archive Interface Control Document INSTRUMENT_PAPER SOIR instrument paper (Applied Optics) TMTC SOIR TM/TC description FLIGHT_USER_MANUAL SPICAV+SOIR Flight User Manual INSTRUMENT_CALIBRATION_PAPER SOIR calibration paper (Applied Optics) INSTRUMENT_DESC short SOIR instrument description SOIR_DATAFILE_DESC contents of the data files which are delivered in the SOIR data set SOIR_CALIBRATION_DESC calibration of the SOIR data which are delivered in the SOIR dataset. INSTRUMENT_MODE_DESC different operating modes of the SOIR spectrometer VEX_POINTING_MODE_DESC different spacecraft pointing modes. VEX_SCIENCE_CASE_ID_DESC 10 different Venus Express science cases VEX_ORIENTATION_DESC usage of the VEX spacecraft orientation OBSERVATION_TYPE_DESC different observation types of SOIR SOIR_DATA_QUALITY description of quality labels in data set Related Data Sets ================= ID NAME ---------------- ----------------------------------------------- VEX-Y/V-SPICAV-2-SOIR-EXT1-V2.0 VENUS EXPRESS SKY/VENUS SPICAV 2 SOIR EXT1 V2.0 VEX-Y/V-SPICAV-3-SOIR-EXT1-V2.0 VENUS EXPRESS SKY/VENUS SPICAV 3 SOIR EXT1 V2.0 Processing ========== The data collected between each switch ON and switch OFF of SOIR is downlinked from the S/C to ESOC and stored on the Data Disposition System (DDS). From there it is retrieved via ftp and stored at BIRA-IASB. PSA data level 1b ----------------- All the data of the precooling phase (answers to TC1 type commands) and all the data of the observation phase (answers to TC2 type commands) are considered, regardless their scientific usefulness. Source files used for level 1b construction are the csv-files at internal SOIR level 0.1. From these source files the PSA data level 1b is constructed resulting in 1 science data table and 2 auxilliary data tables. The science data tables contain all information that can be catalogued per second: time, spectrum, housekeeping. One column is added to distinguish precooling from observation phase data. PSA data level 2 ---------------- After calibration raw internal SOIR level 0.1 data are transformed into calibrated internal SOIR level 0.3 data. During this process only the useful part (= the actual occultation) of the observation phase is considered and spectra are catalogued following the spectral order they were measured in. From these source files the PSA data level 2 is constructed resulting in as many science data tables as there are spectral orders measured in during this observation plus 3 auxilliary data tables. The PDS data set for one occultation consists of science data tables containing time, spectra, housekeeping and attitude data. Attitude data were computed using the most recent and best available SPICE kernels. The quality of the data packets is validated in a DATA_QUALITY_ID which is a 7 bit binary code. Each digit in the code can be set to 0 or to 1. The quality of the data packets is validated in a DATA_QUALITY_ID which is a 8 bit binary code. Each digit in the code can be set to 0 or to 1. The first four bits correspond to error issues. Errors concern measurements for which the results are wrong, due to incorrect telecommand or wrong behaviour of the instrument. The last four bits correspond to warning issues. Warnings are issued when: 1- Detector saturation occurs (ex: too long integration time) 2- The full Sun spectrum can not be corretly defined. The full Sun spectrum is used to calculate the transmittance. It is obtained considering the spectra taken at high tangent altitudes. It has been decided that at least 40 spectra have to be taken before reaching a tangent altitude of 220 km. If it is not the case, different options are considered, as summarized in the table below. The corresponding warning is issued. 3- The full Sun regression spectrum is hard to define, from numeric problems for example. The codes are defined as following: Case | Description ----------+--------------------------------------------------- 0000 0000 | No problem, no warning, occultation usable ----------+--------------------------------------------------- 0001 0000 | Error: No telecommand received 0010 0000 | Error: Detector temperature problem: too high 0011 0000 | Error: Any other kind of error ----------+--------------------------------------------------- 0000 0001 | Warning: Detector saturation 0000 0010 | Warning: 40 points above 200 km 0000 0011 | Warning: 30 points above 200 km 0000 0100 | Warning: 20 points above 200 km 0000 0101 | Warning: 20 points above 180 km 0000 0110 | Warning: 20 points above 160 km 0000 0111 | Warning: 20 points above 140 km 0000 1000 | Warning: 20 points above 120 km 0000 1001 | Warning: 20 points below 120 km 0000 1010 | Warning: Very bad definition of the Sun regression Data ==== Spectral Images --------------- PSA data level 1b ----------------- Files with updated time tag information, housekeeping values, TC copy (standard format). Structure : one file per second throughout complete precooling and observation phase. Data contents : ADC code afo pixel number. PSA data level 2 ---------------- Up to 4 files per second for the selected period (up to 4 orders observed per second). Data contents : transmission afo wavenumber Each data file is accompanied by a detached PDS label. Compression ----------- No compression is performed on the data. Target Name and Description --------------------------- The TARGET_NAME keyword in the data labels is set to ''SUN''. File Naming Convention ---------------------- PSA data level 1b ----------------- ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_OBS.TAB ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_OBS.LBL ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC1.TAB ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC1.LBL ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC2.TAB ./VEX-Y_V-SPICAV-2-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC2.LBL with : * YYYY = year * MM = month * DD = day * T = measurement type * CC = chronological mesurement number of the day (starting at 1) T (measurement type) can have the following values : * I = Ingress (occultation) * E = Egress (occultation) * M = Miniscan * F = Fullscan (outside atmosphere) * A = Fullscan (inside atmosphere) * N = Nadir * C = Pointing calibration PSA data level 2 ---------------- ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_xxx.TAB ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_xxx.LBL ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_Rxxx.TAB ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_Rxxx.LBL ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC2.TAB ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TC2.LBL ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TRT.TAB ./VEX-Y_V-SPICAV-3-SOIR-V2.0/DATA/YYYYMMDD_TCC/YYYYMMDD_TCC_TRT.LBL with : * YYYY = year * MM = month * DD = day * T = occultation type * CC = chronological mesurement number of the day (starting at 1) * xxx = order number T can have the following values : * I for an ingress occultation * E for an egress occultation Parameters ========== Instrument Modes ---------------- SOIR spectra contained within one observation may be taken in either of 3 modes : (1) AOTF frequency hopping : During each observation up to 4 random AOTF frequencies (hopping) and hence non-contiguous small wavelength domains are recorded. (2) Single parameter stepping : During each observation a series of up to 4 wavelength domains is recorded. The parameters defining each of the domains are identical, except one which is incremented by a fixed amount from domain to domain. Can be executed either continuous from one observation to the next or reset to a value specified by TC at each observation. A special case of single parameter stepping is AOTF frequency stepping : the AOTF frequency is incremented by a fixed frequency step for each sequential spectral domain, while all other parameters remain unchanged. (3) Automatic window stepping : The detector is read-out completely by reading sequentially windows of 8 lines. Observations start with the detector window positioned at line 1 and for subsequent observations the window is shifted by 8 lines. In total 32 observations are required to read out the complete detector array. Time-Related Keywords --------------------- START_TIME : the time of data acquisition of the first record (in UTC) STOP_TIME : the time of data acquisition of the last record (in UTC) SPACECRAFT_CLOCK_START_COUNT : the value of the spacecraft clock at the beginning of data acquisition of the first record SPACECRAFT_CLOCK_STOP_COUNT : the time on the spacecraft clock at the end of data acquisition of the last record Geometry-Related Keywords ------------------------- Some geometry information can be found in the data labels : ORBIT_NUMBER : spacecraft orbit during which this data were collected. Valid values are [''N/A''] during the CRUISE phase or the value of the orbit (e.g.[''103'']) during the VENUS phase. SPACECRAFT_ORIENTATION : orientation vector of the spacecraft. The definition of the vector and the standard values are given via the SPACECRAFT_ORIENTATION_DESC pointer SPACECRAFT_ORIENTATION_DESC : pointer to a file containing information about the spacecraft orientation SPACECRAFT_POINTING_MODE : pointing mode of the spacecraft. The definition of the modes and the standard values are given via the SPACECRAFT_POINTING_MODE_DESC pointer SPACECRAFT_POINTING_MODE_DESC : definition file of the different pointing modes of the spacecraft VEX: OCCULTATION_ENTRY_TIME (PENS): time of penumbra start during sunset observation VEX: OCCULTATION_EXIT_TIME (PENE) : time of penumbra end during sunrise observation Some geometry information can be found in the data tables : TangH (GEO) : Tangential Height of the Geometrical Line-of-sight of the Spacecraft to the sun TPointLong (GEO) : Longitude of the Previous geometrical tangential point on the Venus surface TPointLat (GEO) : Latitude of the Previous geometrical tangential point on the Venus surface Theta (GEO) : (see figure 10 in GEO_VENUS index) use GEO values SubSatPointLong (GEO) : Longitude of the closest point on the Venus surface to the Spacecraft SubSatPointLat (GEO) : Latitude of the closest point on the Venus surface to the Spacecraft TangH (BORESIGHT) : Tangential Height of the SOIR viewing direction TPointLong (BORESIGHT) : Longitude of the Previous SOIR Bore sight tangential point on the Venus surface TPointLat (BORESIGHT) : Latitude of the Previous SOIR Bore sight tangential point on the Venus surface Theta (BORESIGHT) : see figure 10 in GEO_VENUS index - use BORESIGHT values Dist_VenusSurface_Vex : distance from S/C to surface of Venus Venus radius = 6051.8km Dist_VenusSurface_Sun : distance from Sun to Venus (center to center) Angle_Slit_limb : angle between the SOIR slit direction and the limb, Calculation uses SOIR bore sight values. The angle has a (arbitrarily chosen) sign. SlitHeight : length of the slit parallel to the Venus-surface-normal in the tangential point. It is the full slit height SlitH_Resolution : The resolution of the slit in the Venus atmosphere. Full height resolution TangH(UNDER) : Tangential Height of the bottom side of the sun(geometrical) TangH(UPPER) : Tangential Height of the top side of the sun (geometrical) TangH_ref(UNDER) : Tangential Height of the bottom side of the sun(geometrical) including atmospheric refraction TangH_ref(UPPER) : Tangential Height of the top side of the sun(geometrical) including atmospheric refraction TangH_ref(CENTER) : Tangential Height of the center of the sun (geometrical) including atmospheric refraction LocalTrueSolarTime(GEO) : Local True Solar Time. This value provides a measure of the instantaneous apparent position of the sun at the point of interest. Local True Solar Time is defined as the angle between the extension of the vector from the Sun to the target body and the projection on the target body's orbital plane of a vector from the target body's planetocentric centre to the point of interest. This angle is measured in a counterclockwise direction when viewed from north of the ecliptic plane. LocalTrueSolarTime : this value provides a measure of the instantaneous apparent position of the sun at the point of interest. Local True Solar Time is defined as the angle between the extension of the vector from the Sun to the target body and the projection on the target body's orbital plane of a vector from the target body's planetocentric centre to the point of interest. This angle is measured in a counterclockwise direction when viewed from north of the ecliptic plane. For SOIR boresight. Some geometry information is part of the GEO_VENUS index file : The GEO_VENUS index file is a list of consecutive footprints, one footprint for every observation in the data set. Each footprint consists of a number of lines in the table, each line corresponding to a measurement, i.e. there are as much lines in the footprint as there are seconds in the observation. The footprint however is limited to measurements that have a tangential height of the SOIR boresight between 220 and 40 km (last column in GEO index table). It is possible that for certain measurements (highest or lowest tangential heights) no measurements were taken. In that case N/A values (999.999 or -999.999) are placed in the table for geometric parameters that can not be calculated. Each line in the GEO index table contains a number of geometric parameters describing the exact location of each measurement. The geometric parameters are documented in the corresponding DESCRIPTION fields in the .LBL-file. The 6 parameters describing the footprint are (START_POINT_LATITUDE, START_POINT_LONGITUDE), (CENTER_LATITUDE, CENTER_LONGITUDE), (END_POINT_LATITUDE, END_POINT_LONGITUDE). The CENTER point is the tangential point itself projected on a 60 km altitude shell around Venus. The START point and END point are points at the left and the right of the CENTER point, so that at each measurement (each second) not one point but one line is defined as footprint of the measurement. The complete footprint of the observation is then a sequence of such traces or the contour described by the extremes of the traces (the START and the END points). START and END point are situated in a tangential plain to the planet, perpendicular to the boresight, at a distance of 10 km (when the tangential height is between 40 and 100 km) and at variable distance (when the tangential height is between 100 and 220 km). This variable distance is calculated by linear regression between the 2 following (tangential height, distance to center)-points : (100 km, 10 km), (250 km, 500 km)." CONFIDENCE_LEVEL_NOTE = "This archival data set was reviewed by the Venus Express SPICAV SOIR team prior to submission to the PSA. Products of questionable validity have been omitted." ABSTRACT_DESC = "The Venus Express SPICAV SOIR PSA level 1B data set contains raw measurements from the SOIR channel of the SPICAV spectrometer collected during the cruise and Venus orbit phases" ARCHIVE_STATUS = ACCUMULATING CITATION_DESC = "Neefs,E., VENUS EXPRESS SKY/VENUS 3 SOIR V1.0, VEX-Y/V-SPICAV-3-SOIR-V1.0, Planetary Science Archive, 2008." DATA_SET_TERSE_DESC = "Venus Express SPICAV SOIR PSA level 1B dataset" DATA_OBJECT_TYPE = "TABLE" DATA_SET_COLLECTION_MEMBER_FLG = "N" DETAILED_CATALOG_FLAG = "N" END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = SUN TARGET_TYPE = SUN END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = VEX INSTRUMENT_ID = "SPICAV-SOIR" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "DUBOISSPV032" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_MISSION MISSION_NAME = "VENUS EXPRESS" END_OBJECT = DATA_SET_MISSION END_OBJECT = DATA_SET END