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Apollo 12 ALSEP ARCSAV Level 0a Raw Cleaned Binary Digital Files

NSSDCA ID: PSPG-00917

Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1975-04-03 to 1975-07-01

Description

This collection consists of digital binary files of 24-hour raw cleaned Level 0a data collected by the Apollo 12 Lunar Surface Experiment Package (ALSEP) from 3 April 1975 through 1 July 1975 for the Solar Wind Spectrometer (SWS), Passive Seismic Experiment (PSE), Lunar Surface Magnetometer (LSM), Suprathermal Ion Detector Experiment (SIDE), Cold Cathode Ion Gage Experiment (CCIG), and Lunar Dust Detector (DTREM).

Processing:

These Level 0a data files were the result of cleaning the 24-hour raw Level 0 binary files 'as read' [1] from 7-track ALSEP ARCSAV (telemetry) tapes to remove byte shifts caused by missing bytes, combined bytes, split bytes, etc., that resulted from tape-read errors. This correction was necessary before data can be extracted for a specific experiment. Bit errors were corrected only when such an error was obvious, and thus many bit errors still remain. Those bytes suspected to be affected by bit errors are flagged with the most significant bit of the 8-bit byte turned on (set to 1). Also when two or more Level 0 files were available, either the file that clearly has the better quality was used, or more often the better sections from multiple Level 0 files were used. The latter always was the case when JBI prematurely stopped recording.

The computer programs and supplemental inputs used to produce the binary data in this collection are available in this selected reference by Nakamura (2020): https://nssdc.gsfc.nasa.gov/misc/documents/b56522.pdf

File Format:

These data are direct-access binary files of 6400-byte fixed-length records written exactly in the ARCSAV data format as described in ALSEP Archive Tape Description Document, JSC-09652 [2]. Since data from the various experiments are intermeshed in these files, users should refer to this document, which describes the bit organization for extracting the data for the experiment of interest, in conjunction with the Apollo Scientific Experiments Data Handbook [3]. For a discussion of how Level 0 data were extracted from the ARCSAV tapes, see 'Description of ARCSAV files as produced by JBI, DBDS and KDM' [4] and 'ARCSAV Tape versus File Names' [5] which cross-reference the ARCSAV tapes to the Level 0 binary files [1] which are the source for these Level0a data.

Background:

This restoration effort began by extracting data 'as read' [1] from 7-track ALSEP ARCSAV tapes that were recovered from the Washington National Records Center (WNRC) in 2010 [6, 7]. Each tape contains 24-hour, time-edited, raw data (not decommutated) from instruments for the ALSEP station deployed near the Apollo 12 landing site. The NASA Johnson Space Center recorded approximately 5000 ALSEP ARCSAV tapes from April 1973 to February 1975 for Apollo 12, 14, 15, 16, and 17 but so far only 439 of them containing data from April through June 1975 have been found at the WNRC [7].

Users should refer to the 'ALSEP Termination Report' [8] which describes the ALSEP experiments for Apollo 11 through Apollo 17 and gives pertinent operational history for each experiment.

References:

[1] ALSEP Raw Binary Digital Files 'as read' from ARCSAV Tapes (for Apollo 12), NSSDCA Data Collection PSPG-00912, NASA Goddard Space Flight Center, Greenbelt, MD, USA, 2018. (https://nssdc.gsfc.nasa.gov/nmc/datasetDisplay.do?id=PSPG-00912 )

[2] Apollo Lunar Surface Experiments Package Archive Tape Description Document, JSC-09652, NASA Johnson Space Center, Houston, Texas, USA, May 1975. (https://repository.hou.usra.edu/handle/20.500.11753/42 ; also available as NSSDCA document B56514-000A, https://nssdc.gsfc.nasa.gov/misc/documents/b56514.pdf )

[3] Lauderdale, W. W., and W. F. Eichelman, Apollo Scientific Experiments Data Handbook, NASA Technical Memorandum, NASA-TM-X-58131, JSC-09166, Houston, Tex., Aug. 1974, updated Aug. 1976. (https://repository.hou.usra.edu/handle/20.500.11753/17 or https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19760007062.pdf ; also available as NSSDCA document B22807-000A, https://nssdc.gsfc.nasa.gov/misc/documents/b22807.pdf )

[4] Nakamura, Y., Description of Apollo ARCSAV tape files as produced by JBI, DBDS and KDM, with Addendum, Institute for Geophysics, University of Texas, Austin, Texas, 29 Nov. 2016, updated Dec. 2016 and Oct. 2017. (NSSDCA document B56515-000A, https://nssdc.gsfc.nasa.gov/misc/documents/b56515.pdf )

[5] Nakamura, Y., ARCSAV Tape versus File Names, Institute for Geophysics, University of Texas, Apr. 2017. (NSSDCA document B56516-000A, https://nssdc.gsfc.nasa.gov/misc/documents/b56516.pdf )

[6] Nagihara, S. et al., Availability Of Previously Unprocessed ALSEP Raw Instrument Data and Derivative Data and Metadata Products, 47th Lunar and Planetary Science Conference, held March 21-25, 2016 at The Woodlands, Texas, Lunar and Planetary Institute Contribution No. 1904, p. 1194, Mar. 2016. (https://www.hou.usra.edu/meetings/lpsc2016/pdf/1194.pdf )

[7] Nagihara, S., et al., Search and Recovery Efforts for the ALSEP Data Tapes, 42nd Lunar and Planetary Science Conference, held March 7-11, 2011 at The Woodlands, Texas, Lunar and Planetary Institute Contribution No. 1608, p. 1103, Mar. 2011. (https://www.lpi.usra.edu/meetings/lpsc2011/pdf/1103.pdf )

[8] Bates, J. R., et al., ALSEP Termination Report, NASA Reference Publication, NASA-RP-1036, Houston, Tex., Apr. 1979. (https://repository.hou.usra.edu/handle/20.500.11753/16 or https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790014808.pdf ; also available as NSSDCA document B32116-000A, https://nssdc.gsfc.nasa.gov/misc/documents/b32116.pdf )

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Yosio NakamuraGeneral ContactUniversity of Texas, Austinyosio@utig.ig.utexas.edu

Selected References

  • Lauderdale, W. W., and W. F. Eichelman, Apollo scientific experiments data handbook, NASA, TM-X-58131, Houston, Tex., Aug. 1974, updated Aug. 1976.
  • Bates, J. R., et al., ALSEP termination report, NASA, RP-1036, Wash., DC, Apr. 1979.
  • Nakamura, Y., Apollo Lunar Surface Experiment Package Archive Tape Description Document (ARCSAV), NASA Johnson Space Center, JSC-09652, Houston, TX, May 1975.
  • Nakamura, Y., Description of Apollo ARCSAV tape files as produced by JBI, DBDS and KDM, with Addendum, Institute for Geophysics, University of Texas, Austin, Texas, 29 Nov. 2016, updated Dec. 2016 and Oct. 2017.
  • Nakamura, Y., Index of Apollo ARCSAV Tape Versus File Names, Institute for Geophysics, University of Texas, Austin, Texas, Apr. 2017.
  • Nakamura, Y., Apollo ARCSAV Level 0a (Raw Cleaned Binary) File Processing Programs and Supplementary Input Files, Institute for Geophysics, University of Texas, Austin, Texas, Apr. 2020.
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