Data Set Information
DATA_SET_NAME MSL MARS ALPHA PARTICLE X-RAY SPECTROMETER 2 EDR V1.0
DATA_SET_ID MSL-M-APXS-2-EDR-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The Alpha-Particle X-Ray Spectrometer (APXS) is a contact instrument that uses X-ray spectroscopy to determine the elemental composition of soils and rocks. Atmosphere argon can also be measured by the APXS. The APXS is deployed on selected targets along the rover traverse to determine the elemental composition of samples. Materials processed by the Sample Acquisition - Sample Processing and Handling (SA/SPaH) system can also be delivered to the observation tray or to the martian surface for analysis by APXS. Elements heavier than Na can be detected by APXS. If present at sufficient levels, the abundances of these elements can also be determined. The instrument consists of a sensor head mounted on the rover's Robotic Arm (RA) component of the MSL SA-SPaH tools suite, and electronics mounted in the Rover Chassis. The APXS has access to an onboard calibration targets for post-landing calibration. The MSL APXS includes a Peltier cooler for the detector chip that can be activated to achieve better performance at daytime ambient temperatures. A total observation time of 2 to 3 hours is necessary for a full analysis; however, it is also possible to perform a quick analysis in about 15 minutes. For those familiar with the Mars Exploration rover (MER) APXS, these MSL observations times are shorter due to the different source-detector geometry. Other significant differences from MER include the cooler which expands daytime operations, and the need to transfer data to the rover computer prior to instrument power down (no memory backup). Similar to operations on MER, the rover may go to sleep to conserve energy once the APXS acquisition has started; however, the rover must be awake to stop the observation and retrieve the data. Processing : APXS EDR data products are considered CODMAC Level 2 or Edited Data (equivalent to NASA level 0) products. The EDR data files are generated from Level 1 or Raw Data, which are the telemetry packets within the project specific Standard Formatted Data Unit (SFDU) record. The APXS EDR data products will be generated by the MIPL (Multimission Image Processing Laboratory) at JPL under the Operations Product Generation System (OPGS). The EDR data products will be raw uncalibrated data reconstructed from telemetry data products in the format described by the APXS EDR SIS. Meta-data collected when the rover prepared the science data for downlink will be provided in PDS label. There will be multiple versions of an APXS EDR. If telemetry data is missing during the initial downlink from the rover memory, partial data sets will be created and the missing data will be filled with zeroes. The data will be reprocessed after all data are received and the original version will be overwritten. There can be up to 2 EDRs created, one with a status of partial and the other with a complete status in the filename. Data : Each APXS EDR will consist of two files. The first file is an ASCII formatted detached PDS label. The second file is a binary data file. The APXS EDR data file is a copy of what was in the APXS memory buffer. That is, the EDR consists of unprocessed experiment data stored in binary format along with additional Rover FSW meta-data. The instrument holds data for the thirteen most recent measurements in memory. When a new measurement begins, the oldest one is discarded. Each spectrum has a unique identifier. There is also a data block containing instrument engineering data. There are 2 types of APXS EDRs: the APXS Science EDR and the APXS CWA (Current Working Area) EDR. The science EDR contains all 13 measurements and the engineering data. The CWA EDR only contains the most recent measurement.
DATA_SET_RELEASE_DATE 2012-03-15T00:00:00.000Z
START_TIME 2012-07-16T12:00:00.000Z
STOP_TIME N/A (ongoing)
MISSION_NAME MARS SCIENCE LABORATORY
MISSION_START_DATE 2003-10-01T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME MARS
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID MSL
INSTRUMENT_NAME ALPHA PARTICLE X-RAY SPECTROMETER
INSTRUMENT_ID APXS
INSTRUMENT_TYPE SPECTROMETER
NODE_NAME Geosciences
ARCHIVE_STATUS IN_LIEN_RESOLUTION
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : The data presented in the APXS EDR is intended to be the least processed, most primitive data set released for APXS. Data presented here are an accurate representation of APXS data as received from the rover. Review : The APXS EDR products are reviewed internally by the APXS team prior to release to the PDS. PDS also performs an external peer review of the APXS EDR. Data Coverage and Quality : Data reported are the minimally processed data received from the orbiter during nominal APXS operations. All data received is reformatted into the EDR data. Data are by definition of good quality, as damaged telemetry packets are sequestered upon receipt from the spacecraft. We do not expect to receive many (if any) damaged data packets. Limitations : The major limitation of this data set is that this is level 0, minimally processed data. The data are received from the spacecraft telemetry and ingested into a database. If gaps exist in the telemetry, data are lost. Data Compression : No data compression is used.
CITATION_DESCRIPTION Gellert, R., Mars Science Laboratory Alpha Particle X-Ray Spectrometer EDR Data V1.0, MSL-M-APXS-2-EDR-V1.0, NASA Planetary Data System, 2012.
ABSTRACT_TEXT Unprocessed experiment data copied from the memory buffer of the APXS instrument aboard the Mars Science Laboratory rover.
PRODUCER_FULL_NAME RALF GELLERT
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