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Pioneer 11 TRD Cruise Data Archive


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

Time span: 1973-04-16 to 1991-08-31


Thirty minute averages of energetic particle counts, encoded currents, livetimes, ephemeris parameters, and housekeeping information are provided from Trapped Radiation Detector (TRD) operation during interplanetary cruise from launch in UCSD's homogenous summary format. The most useful interplanetary data could be used to calculate counting rates and fluxes for protons above integral thresholds of 80 and 500 MeV. The dataset was packaged in SFDU format with metadata files describing the spacecraft, experiment, data channels, and formats of ASCII fields for dataset parameters. There were 27 separate channels of data, divided between 21 channels of pulse counting data and 6 channels of encoded electrometer data. However, the electrometer data channels are too insensitive to be useful in interplanetary space, and also, the electrometer rate commutator failed one month after launch, so these rates were mixed and could not be used. Counting rates for each pulse channel could be obtained from division of counts per accumulation period by the length of the accumulation period to obtain counting rates for any desired time averaging interval while preserving valid statistical information. Each data record of fixed length 1800 bytes contained 221 formatted ASCII fields for data parameters and field delimiters. Data records were synchronized to begin and end every half hour on the half hour in Spacecraft Event Time (UT). New records were also started whenever the spacecraft bit rate or format changed. The dataset consists of two metadata files followed by separate data files for each consecutive six-month interval. Further information on the TRD interplanetary measurements was published in Axford, W.I., W. Fillius, L.J. Gleeson, and W.-H. Ip, ``Cosmic-Ray Gradients from Pioneer-10 and Pioneer-11,'' Astrophys. J., 210, 603-613, Dec. 1, 1976.

Alternate Names

  • 30 min Interplanetary Data,SFDU
  • 30 minute TRD Interplanetary Data, SFDU


  • Space Physics: Heliospheric Studies


  • 73-019A-05H

Additional Information



Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. R. Walker FilliusGeneral ContactUniversity of California, San
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