PDS_VERSION_ID = PDS3 RECORD_TYPE = "STREAM" LABEL_REVISION_NOTE = " 2015-09-01, S. Joy/E. Ammannito - initial version; 2016-01-25, J. Mafi - Corrected peer review liens; 2016-03-25, J. Mafi - HAMO Update; 2016-09-07, S. Joy - Added data coverage table; 2016-09-26, J. Mafi - HAMO peer review corrections; 2017-05-31, J. Mafi - Updated Dawn Science Observations and Summary of Data Acquisition Plan and Losses tables; 2017-07-14, J. Mafi - Corrections to data coverage descriptions; 2018-03-12, J. Mafi - Updated for CXG and CXO; " OBJECT = DATA_SET DATA_SET_ID = "DAWN-A-VIR-2-EDR-VIS-CERES-SPECTRA-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = " DAWN VIR RAW (EDR) CERES VISIBLE SPECTRA V1.0" DATA_SET_TERSE_DESC = "Contains raw visible data from the DAWN spacecraft VIR instrument during the Ceres Encounter mission phases." ABSTRACT_DESC = "This volume contains the digital numbers (DN) contained in the telemetry (TM) packages of the VIR-VIS instrument on board of the spacecraft DAWN. The data are from the Ceres Encounter and Extended mission phases, which occurred 2014-12-26 to 2017-04-29." CITATION_DESC = "De Sanctis, M.C., M.T. Capria, M. Giardino, E. Ammannito, S. Fonte, DAWN VIR RAW (EDR) CERES VISIBLE SPECTRA V1.0, DAWN-A-VIR-2-EDR-VIS-CERES-SPECTRA-V1.0, NASA Planetary Data System, 2015." DATA_OBJECT_TYPE = "QUBE" DATA_SET_COLLECTION_MEMBER_FLG = "N" DETAILED_CATALOG_FLAG = "N" DATA_SET_RELEASE_DATE = 2015-09-01 PRODUCER_FULL_NAME = "MARIA CRISTINA DE SANCTIS" ARCHIVE_STATUS = "LOCALLY ARCHIVED" START_TIME = 2015-01-13T19:36:00 STOP_TIME = 2017-04-29T19:08:46 DATA_SET_DESC = " Required Reading ================ The format of all VIR data are described in detail by the SIS document located in the /DOCUMENT directory. VIR team strongly recommends reading this documentation before using the data. Data Set Overview ================= This data set contains raw VIS data acquired by the DAWN mission VIR spectrometer during the Ceres Encounter and Extended Mission phases of the DAWN mission, which covered December 26, 2014 to April 29, 2017. VIR Ceres Observations ====================== The following table contains a listing of VIR observations at Ceres. ------------------------------------------------------------------------ Dawn Science Observations ------------------------------------------------------------------------ Start Mission Activity Activity Date Phase Name Description ======================================================================== 14-12-26 CSA APPROACH Ceres Science Approach Phase ------------------------------------------------------------------------ 15-01-13 CSA OPNAV_001 Ride-along cubes to FC OpNav images - 4 obs 15-01-25 CSA OPNAV_002 Ride-along cubes to FC OpNav images - 4 obs 15-02-04 CSA OPNAV_003 Ride-along cubes to FC OpNav images - 5 obs 15-02-12 CSA RC1 Ride-along cubes to FC rotational - 10 obs characterization movie #1 - 8 obs 15-02-19 CSA RC2 Ride-along cubes to FC rotational - 3 obs characterization movie #2 - 3 obs 15-02-25 CSA OPNAV_004 Ride-along cubes to FC OpNav images - 3 obs 15-03-01 CSA OPNAV_005 Ride-along cubes to FC OpNav images - 3 obs 15-04-10 CSA OPNAV_006 Ride-along cubes to FC OpNav images - 3 obs 15-04-15 CSA OPNAV_007 Ride-along cubes to FC OpNav images - 3 obs ======================================================================== 15-04-24 CSR RC3 Ceres Science Rotational Characterization 3 ------------------------------------------------------------------------ 15-04-25 CSR RC3 RC3 Equator Limb 1 (S) high phase - 10 obs 15-04-30 CSR RC3 RC3 Equator Limb 2 (N) high phase - 16 obs 15-05-04 CSR RC3n RC3 North lit side - 16 obs 15-05-05 CSR RC3e RC3 Equator lit side - 16 obs 15-05-07 CSR RC3s RC3 South lit side - 16 obs ------------------------------------------------------------------------ 15-05-09 CTS TRANSFER_ Ceres Transfer to Survey Phase TO_Survey ------------------------------------------------------------------------ 15-05-16 CTS OPNAV_008 Ride-along cubes to FC OpNav images - 7 obs 15-05-22 CTS OPNAV_009 Ride-along cubes to FC OpNav images - 7 obs ------------------------------------------------------------------------ 15-06-04 CSS SURVEY Ceres Science Survey Phase (range ~4850 km) ------------------------------------------------------------------------ 15-06-04 CSS CYCLE1 Survey Cycle (orbit) 1 - 44 obs 15-06-08 CSS CYCLE2 Survey Cycle (orbit) 2 - 49 obs 15-06-11 CSS CYCLE3 Survey Cycle (orbit) 3 - 44 obs 15-06-14 CSS CYCLE4 Data lost to instrument reset, sci data lost 15-06-17 CSS CYCLE5 Survey Cycle (orbit) 5 VIS-only - 51 obs 15-06-21 CSS CYCLE6 Survey Cycle (orbit) 6 VIS bad - 50 obs 15-06-24 CSS CYCLE7 Survey Cycle (orbit) 7 VIS-only - 49 obs 15-06-27 CSS CYCLE8 Data lost to instrument reset, sci data lost ------------------------------------------------------------------------ 15-07-01 CTH TRANSFER_ Ceres Transfer to HAMO Phase TO_HAMO ------------------------------------------------------------------------ No science observation in this phase ------------------------------------------------------------------------ 15-08-17 CSH HAMO Ceres Science HAMO Phase (avg rng ~1950 km) ------------------------------------------------------------------------ 15-08-17 CSH CYCLE1 12 orb pushbroom nadir imaging - 62 obs 15-08-29 CSH CYCLE2 12 orb pushbroom off-nadir imaging - 71 obs 15-09-09 CSH CYCLE3 12 orb pushbroom off-nadir IR-only - 108 obs 15-09-20 CSH CYCLE4 12 orb pushbroom off-nadir imaging - 85 obs 15-10-01 CSH CYCLE5 12 orb pushbroom near nadir IR-only - 84 obs 15-10-12 CSH CYCLE6 12 orb pushbroom off-nadir IR-only - 73 obs ------------------------------------------------------------------------ 15-10-23 CTL TRANSFER_ Ceres Transfer to LAMO Phase TO_LAMO ------------------------------------------------------------------------ No science observation in this phase ------------------------------------------------------------------------ 15-12-16 CSL LAMO Ceres Science LAMO Phase (range ~850 km) ------------------------------------------------------------------------ 15-12-16 CSL CYCLE0 nadir pushbroom imaging IR-only - 2 obs 15-12-18 CSL CYCLE1 nadir pushbroom imaging IR-only - 9 obs 16-01-10 CSL CYCLE2 nadir scan mirror imaging IR-only - 11 obs 16-02-02 CSL CYCLE3 nadir scan mirror imaging IR-only - 15 obs 16-02-25 CSL CYCLE4 nadir scan mirror imaging IR-only - 18 obs 16-03-19 CSL CYCLE5 off-nadir scan mirror IR-only - 34 obs 16-04-11 CSL CYCLE6 off-nadir scan mirror IR-only - 30 obs 16-05-04 CSL CYCLE7 off-nadir scan mirror imaging - 24 obs 16-05-27 CSL CYCLE8 off-nadir scan mirror imaging - 33 obs ------------------------------------------------------------------------ 16-06-19 CXL XMO1 Ceres Extended LAMO Phase (range ~850 km) ------------------------------------------------------------------------ 16-06-19 CXL CYCLE9 off-nadir scan mirror imaging - 40 obs 16-07-18 CXL CYCLE10 off-nadir scan mirror VIS-only - 38 obs 16-08-10 CXL CYCLE11 off-nadir scan mirror imaging - 29 obs ------------------------------------------------------------------------ 16-09-02 CTJ TRANSFER_ Ceres Transfer to Juling Phase TO_JULING ------------------------------------------------------------------------ No VIR science observations in this phase ------------------------------------------------------------------------ 16-10-10 CXJ XMO2 Ceres Extended Juling Phase (range ~1950 km) ------------------------------------------------------------------------ 16-10-10 CXJ CYCLE1 off-nadir imaging - 12 obs 16-10-24 CXJ CYCLE2 off-nadir imaging - 6 obs ------------------------------------------------------------------------ 16-11-03 CTG TRANSFER_ Ceres Transfer to GRaND Phase TO_GRAND ------------------------------------------------------------------------ No VIR science observations in this phase ------------------------------------------------------------------------ 16-12-14 CXG XMO3 Ceres Extended GRaND Phase (range ~8000- 9500 km) ------------------------------------------------------------------------ 16-12-14 CXG CYCLE1 No science observations 17-01-21 CXG CYCLE2 off-nadir pushbroom imaging VIS-only - 5 obs 17-02-17 CXG CYCLE3 No science observations ------------------------------------------------------------------------ 17-02-23 CTO TRANSFER_ Ceres Transfer to Opposition Phase TO_OPPOSITION ------------------------------------------------------------------------ No VIR science observations in this phase ------------------------------------------------------------------------ 17-04-28 CXO XMO4 Ceres Extended Opposition Phase (range 14-55E3 km) ------------------------------------------------------------------------ 17-04-29 CXO Opposition off-nadir scann mirror imaging - 7 obs Processing ========== The data in this data set are raw, CODMAC Level 2 data. As such, no processes have been applied to the data other than decompression and reformatting as cubes. Data ==== The data are in PDS format. A detailed description of the data format is given in the VIR SIS document located in the DOCUMENT directory of this data set. Ancillary Data ============== No ancillary data included in this data set. Coordinate System ================= The geometry items SC_SUN_POSITION_VECTOR, SC_TARGET_POSITION_VECTOR and SC_TARGET_VELOCITY_VECTOR provided in the label of the data product are relative to the Earth Mean Equator frame of J2000. SUB_SPACECRAFT_LATITUDE, SUB_SPACECRAFT_LONGITUDE are given in the PLANETOCENTRIC coordinate system. These parameters are corrected for planetary and stellar aberrations. Distances are given in km, angles in degrees. " CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview ========================= Data confidence is nominal, meaning that all data have been validated by the VIR team and found as expected. Any exceptions are noted by the DATA_QUALITY field in the label files. Following the loss of the 2nd reaction wheel during Vesta departure, Dawn had to rely on the RCS thrusters, rather than reaction wheels, to maintain pointing. While the Dawn system does not employ true dead-banding, the net result of the thruster firings is to introduce pointing offsets of up to +/- 0.64 degrees in +X and +Y, and rates of up to 0.01 degrees/second (or ~ 0.7 VIR pixels/second). The combination of long VIR integration times with large pointing and pointing rate errors complicates interpreting the data acquired as normal spectral cubes. When Dawn is near to Ceres, the timing of the thruster firings is moderately predicable with the most common attitude near one of the deadband limits. When Dawn is far from its selected target the thruster firing is more random and the impact of not being pointed at Ceres nadir is amplified. This is especially apparent in the VIR cubes since each frame of the cube effectively has its own pointing. During Approach and RC3, Ceres is highly distorted in the raw data cubes and care must taken to properly correct the geometry when calibrating and interpreting these data. Review ====== These are the same data files that were utilized by the Dawn Science Team. Any errors or deficiencies reported by the Science Team were corrected by the VIR team. Note, however, that the geometry information provided in the PDS labels was updated to reflect the IAU coordinate system updated to Dawn derived pole right ascension and declination values. A full PDS peer review was conducted of all products in this data set. Data Coverage and Quality ========================= Data coverage is good unless otherwise noted by the DATA_QUALITY keyword. Dropouts that may be observed in some images are due to instrument saturation. The spectral range in which these dropouts occur varies depending upon exposure duration, target topography, and incidence angle. The spacecraft safed as it entered the RC3 mission phase. As a result, the cubes in the first rotation of the RC3 Equatorial Limb 001 (South) high phase observations were lost. The VIR instrument reset in Survey Cycles 4 and 8 before any science data were discharged to spacecraft memory so only the cal lamp cubes were preserved. Prior to and during the first few orbits of the Survey mission phase, the VIR cryocooler began showing signs of aging. As a result, Survey Cycles 5 and 7 were acquired in VIS-only mode with the cryocooler turned off to preserve it for use during the HAMO mission phase. In Cycle 6 both IR and VIS data were collected, however, the VIS spectra had integration times near zero. As a result the VIS data for Survey Cycle 6 are not useful for science and have been omitted from the L-1B (RDR) data volume. During the HAMO mission phase, the cryocooler set point was raised from 75 deg Kelvin to 80 deg Kelvin to reduce the strain on the cooler. There is a slight decrease in the signal to noise ratio as a result of running the cooler at a warmer temperature. Cycles 3 and 5 of HAMO were acquired in IR-only mode in order to increase the number of IR frames that could be acquired. Orbit 6 of HAMO cycle 1 was also an IR-only orbit. After HAMO sequences were initially built and delivered to the Dawn project, the team decided to reduce the repetition time between frames in each cube. This reduced the size of the gaps between frames within cubes but increased the gaps between cubes. In LAMO Cycle 5, the cryocooler began to exhibit signs of further deterioration. In Cycle 6, IR cubes were acquired with set points of 80, 83, and 87 deg K. After examination of the signal to noise ratio, the instrument team determined that the set point could be raised to 85 deg K with minimal impact. Summary of Data Acquisition[1] Plan and Losses ======================================================================== Mission IR IR IR VIS VIS VIS Phase Cubes Cubes Frames Cubes Cubes Frames Activity Plan Lost Lost Plan Lost Lost Comment ======================================================================== CSA OpNav1 3 0 0 3 0 0 CSA OpNav2 3 0 0 3 0 0 CSA OpNav3 4 0 0 4 0 0 CSA RC1 9 0 0 9 0 0 CSA RC2 7 0 0 7 0 0 CSA OpNav4 2 0 0 2 0 0 CSA OpNav5 3 0 0 3 0 0 Lost cal-lamp cubes CSA OpNav6 2 0 0 2 0 0 Lost to DSN outage CSA OpNav7 2 0 0 2 0 0 ------------------------------------------------------------------------ RC3 HPSouth 20 10 1400 20 10 1400 S/C safing RC3 HPNorth 20 0 0 20 0 0 RC3 North 15 0 0 15 0 0 RC3 Equator 15 0 0 15 0 0 RC3 South 15 0 0 15 0 0 ------------------------------------------------------------------------ CTS OpNav8 6 0 0 7 0 0 CTS OpNav9 6 0 0 7 0 0 ------------------------------------------------------------------------ Survey C1 43 0 0 43 0 0 Survey C2 48 0 0 48 0 0 Survey C3 43 0 0 43 0 0 Survey C4 48 48 2880 48 48 2880 VIR reset, sci data lost Survey C5 0 0 0 50 0 0 VIS-only Survey C6 49 0 0 49 0 0 IR-only Survey C7 0 0 0 48 0 0 VIS-only Survey C8 0 0 0 48 48 2915 VIR reset, sci data lost ------------------------------------------------------------------------ HAMO C1 61 0 0 55 0 0 HAMO C2 72 1 78 72 1 78 HAMO C3 108 1 68 0 0 0 IR-only HAMO C4 84 0 0 70 0 0 HAMO C5 84 1 68 0 0 0 IR-only HAMO C6 72 0 0 0 0 0 IR-only ------------------------------------------------------------------------ LAMO C0 16 0 0 0 0 0 IR only LAMO C1 160 88 4400 0 0 0 IR only, DSN? LAMO C2 88 0 0 0 0 0 IR only, DSN? LAMO C3 120 0 0 0 0 0 IR only LAMO C4 147 2 185 0 0 0 IR only, DSN? LAMO C5 275 0 0 0 0 0 IR only LAMO C6 120 30 1560 0 0 0 IR only, segs. aborted [2] LAMO C7 53 0 0 146 0 0 Minor data loss, DSN? LAMO C8 54 40 2282 254 218 11337 Segments aborted [2] ------------------------------------------------------------------------ CXL C9 51 21 1300 192 12 624 CXL C10 0 0 0 454 0 0 CXL C11 15 0 0 140 0 0 multiple plans [3] ------------------------------------------------------------------------ CXJ C1 36 18 900 0 0 0 CXJ C2 24 6 400 0 0 0 ------------------------------------------------------------------------ CXG C1 0 0 0 0 0 0 CXG C2 0 0 0 58 0 0 VIS only CXG C3 0 0 0 0 0 0 ------------------------------------------------------------------------ CXO Opp 1 0 0 19 0 0 ------------------------------------------------------------------------ [1] Cube and frame counts are for science data only and do not include calibration cubes. [2] Segments which were not expect to acquire the planned targets were aborted. [3] CXL C11: Multiple plans were developed for this phase. Ultimately individual segments were selected and run such that the actual data acquisition did not match any of the plans. ------------------------------------------------------------------------ Limitations =========== No limitations on these data" END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_MISSION MISSION_NAME = "DAWN MISSION TO VESTA AND CERES" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_TARGET TARGET_NAME = "1 CERES" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "DAWN" INSTRUMENT_ID = "VIR" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "DESANCTISETAL2010" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END