LRO LAMP Experiment Data Record (EDR)

EDR – Experiment Data Record

Instrument: Lyman-Alpha Mapping Project

PDS Data Set ID: LRO-L-LAMP-2-EDR-V1.0DOI: 10.17189/1520199

For more information about LAMP EDR products, see the EDR Product SIS.

For more details on the structure and contents of the LAMP EDR Archive, see the EDR Archive SIS.

The Lyman-Alpha Mapping Project (LAMP) Experiment Data Record (EDR) data products consist of a single FITS formatted file on a one file per orbit basis containing seven types of data: spectral image (aperture door open), spectral image (aperture door closed), acquisition list, raw frame data, calculated count rate, LTS data, and housekeeping data.

  1. Spectral image (aperture door open): This is a reconstructed histogram generated from the pixel list data in the science data file. When housekeeping data are available, only the pixel list data acquired when the aperture door was open are included in this dataset. Otherwise, all pixel list data are included in this histogram. This summary image is used as a “quick-look” check on data quality. [Extension 0 = primary FITS header and data unit (HDU)]

  2. Spectral image (aperture door closed): This is similar to the first dataset, but the reconstructed histogram here is generated from pixel list data acquired when the aperture door was closed. If housekeeping data are available, this dataset will be empty. This summary image is used as a “quick-look” check on data quality. [Extension 1]

  3. Acquisition list: This dataset contains a list of the generated frame acquisitions as determined from the housekeeping data file. The list includes, for each frame, the instrument frame sequence number, start and stop times, mode type, aperture door and other instrument state information. The frame acquisition times and instrument state data contained in this list are used to cross-reference with the pixel list mode data for purposes of selecting data and checking timing consistency. [Extension 2]

  4. Raw frame data: This dataset contains all of the raw data from the science data file except for the file header. [Extension 3]

  5. Calculated count rate: This dataset contains a high-resolution sequence of UV photon count rates computed from the pixel list data for each acquisition (nominally the whole orbit). The resolution of this count rate sequence depends on the commanded “hack time” interval. If no pixel list science data are available, e.g., if data are acquired only in histogram mode, then this dataset will be empty. This sequence will be used to assess the variation in bulk far-UV signal throughout the orbit, and may be especially useful when trending data obtained near the terminator or during exceptional events (e.g., solar flares). [Extension 4]

  6. LTS data: LAMP housekeeping data contain up to 10 values per second of gain and offset corrected measurement values from each of the two LAMP Lunar Terminator Sensors (LTS). This dataset provides the full 10-Hz LTS dataset. These coincident LTS data will be used with the count rate sequence in the calculated count rate to confirm that LAMP is viewing the appropriate day/night/shadow scenes. [Extension 5]

  7. Housekeeping data: This dataset contains the complete housekeeping dataset, both in raw format and, where applicable, in calibrated engineering units. HK data are included here to assist with joint instrument and data quality trending analyses (foreseen and unforeseen). [Extension 6].

The primary data in the LAMP EDR files are contained in the raw data frames in Extension 3 of the FITS files. The data have not been calibrated or located in space. Normally, each LAMP EDR data product contains observational data taken during a single LRO orbit. Thus, using a value of 113 minutes for the orbital period of LRO, LAMP generates approximately 13 data product files per day.

LAMP EDR products have the following file names:

LAMP_ENG_nnnnnnnnnn_vv.FIT (with detached PDS label)

where:

nnnnnnnnnn = 10-digit time stamp value, namely the Spacecraft UT (SCUT) of the start of the file

vv = 2-digit version number to facility unique identification of (possibly reprocessed) EDR data files

In ODE, EDR products have the following product IDs:

LAMP_ENG_NNNNNNNNNN_VV.FIT