Data Set Information
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| DATA_SET_NAME |
LCROSS EARTH/MOON VISIBLE SPECTROMETER 2 RAW V1.0
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| DATA_SET_ID |
LCROSS-E/L-VSP-2-RAW-V1.0
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| NSSDC_DATA_SET_ID |
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| DATA_SET_TERSE_DESCRIPTION |
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| DATA_SET_DESCRIPTION |
Data Set Overview : This data set contains raw spectra from the LCROSS Visible Spectrometer (VSP). This instrument's boresight was parallel to the payload reference boresight (Near Infrared Spectrometer #1). After the centaur impact, the spacecraft kept the impact site within the field of view of this instrument until shortly before its own impact. Each file in this dataset contains a 1024 pixel spectra plus 20 reference pixels in an ascii, single-column, tabular format. Integration time varied and is noted in the labels. The spectrometer's field of view was circular and 1 degree in diameter. The spectra in this dataset have targets named Moon, Earth and Calibration (i.e., not targeted). The time each spectra was captured is encoded in the spectra's filename like this: LCROSS_VSP_RAW_.IMG where : YYYYMMDDHHMMSSmmm and YYYY : the four digit year; MM : the two digit month, DD : the two digit day, and so on through hours, minutes, seconds and milliseconds. The detached label for each spectra has the same filename as the spectra but with the 'LBL' extension. This dataset encompasses all raw spectra collected by the VSP during the mission. Note that the archive's DATA directory is partitioned initially by payload data collection period. The data collection period called 20091009113022_IMPACT contains the data from one minute prior to the Centaur impact through the end of the mission. Other data collection periods periods contain data from various calibration targets. Related Data Sets : The VSP_CAL dataset contains the calibrated versions of the spectra in this dataset. Parameters : Science ------- Integration time varies between spectra and is noted in milliseconds by the EXPOSURE_DURATION attribute in the label files. Housekeeping ------------ Instrument temperature at the data collection time is reported in the label file under: INSTRUMENT_TEMPERATURE and INSTRUMENT_TEMPERATURE_COUNT in degrees Centigrade and raw counts, respectively. This is a single telemetry point most representative of the instrument chassis temperature. The thermoelectric cooler control setpoint and best-estimate detector temperature temperature are noted in degrees centigrade in the LCROSS:TEC_SETPOINT and LCROSS:TEC_TEMPERATURE attributes, respectively. The VSP implemented a 'bracket' exposure mode intended to vary the integration time to compensate for uncertainty about the expected scene. In this mode, the spectrometer captured three spectra in quick succession with short, medium and long integration times. Other than integration time, no other aspect of data collection was changed. This aspect of VSP data collection is visible in the LCROSS:VSP_BRACKET_NUMBER and LCROSS:PACKET_TIMESTAMP attributes, which allow PDS-formatted spectra to be tracked back to the slot in the telemetry packet they were created from. Processing : Each visible and ultraviolet light spectra was digitally transmitted from the spectrometer to the spacecraft with error detection, inserted into a packet uncompressed and downlinked in telemetry. On the ground, the spectra were extracted from telemetry and converted to CSV format. The LCROSS Make Archive program read these files and wrote them as PDS-formatted (.TAB) and label (.LBL) files. Data : The files in this dataset are PDS-formatted, ascii, single-column tables with detached label files. Each table contains one 1024 pixel spectra in its first 1024 rows, followed by 20 reference pixels. File rows [1031,1032] inclusive may be used as dark pixels. They are at the long wavelength end of the spectrometer. Rile rows [1036,1038] inclusive may also be used as dark pixels, and they are at the short wavelength end. All other, non-spectral rows are unused. These indices label the first row of the file as row #1. Coordinate System : TBD Software : The GSEOS Version used to generate these spectra is GSEOS 5.2.407 (Feb 25, 2008), Python 2.2.3 (#37, Nov 28, 2003, 04:20:20), Project Version 6.1.064. The LCROSS.py Python script used with GSEOS is Version Jun 11, 2008. The LCROSS Report Generator used on GSEOS created CCSDS.dat files is version 114. The version of Satellite Toolkit used to prepare geometric information for the labels is 8.1.3. The LCROSS Make Archive program used to assemble the PDS-formatted submission is dated 03/14/2010.
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| DATA_SET_RELEASE_DATE |
2010-03-17T00:00:00.000Z
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| START_TIME |
2009-06-20T02:00:00.000Z
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| STOP_TIME |
2009-10-09T11:36:00.000Z
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| MISSION_NAME |
LUNAR CRATER OBSERVATION AND SENSING SATELLITE
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| MISSION_START_DATE |
2009-04-27T12:00:00.000Z
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| MISSION_STOP_DATE |
2009-10-09T12:00:00.000Z
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| TARGET_NAME |
CALIBRATION
EARTH
MOON
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| TARGET_TYPE |
CALIBRATION
PLANET
SATELLITE
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| INSTRUMENT_HOST_ID |
LCROSS
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| INSTRUMENT_NAME |
VISIBLE SPECTROMETER
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| INSTRUMENT_ID |
VSP
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| INSTRUMENT_TYPE |
VISIBLE SPECTROMETER
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| NODE_NAME |
Geosciences
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| ARCHIVE_STATUS |
LOCALLY_ARCHIVED
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| CONFIDENCE_LEVEL_NOTE |
Confidence Level Overview : The confidence level is unspecified. Review : This LCROSS data set was reviewed internally by the LCROSS science team before delivery to PDS. This data set has passed a PDS peer review. Data Coverage and Quality : This data path from spectrometer to PDS involved no lossy compression and was fully error corrected. No VSP packets were lost in downlink. During the preimpact and impact data collection periods, the VSP was miscommanded due to delays associated with an overloaded science computer (DHU). This resulted in some spectra with integration times different from those intended. Also, in the case of 10 out of 1873 spectra, the reported integration times were incorrect, and these times have been corrected. After correction, the integration times in the label files reflect what actually occurred. Some VSP spectra were saturated. These are flagged in the label files by the LCROSS:SATURATION_FLAG attribute. Limitations : Noted under data coverage and quality. Data Compression : No data compression was used in the datapath from the detector to the formatted files ready for submission to the PDS.
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| CITATION_DESCRIPTION |
Colaprete, A., Lunar Crater Observation and Sensing Satellite Visible Spectrometer Raw Data V1.0, LCROSS-E/L-VSP-2-RAW-V1.0, NASA Planetary Data System, 2010.
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| ABSTRACT_TEXT |
Raw, uncalibrated spectra from the Visible Spectrometer (VSP) aboard the Lunar Crater Observation and Sensing Satellite (LCROSS).
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| PRODUCER_FULL_NAME |
ANTHONY COLAPRETE
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| SEARCH/ACCESS DATA |
LCROSS Analysts Notebook
LCROSS FTP Resource
GEOSCIENCES WEB SERVICES
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