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Pioneer 11 Solar Wind Plasma Spectra


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

Time span: 1973-04-06 to 1993-05-26


This data set provides the primary Level 1 archive of telemetry data from the Plasma Analyzer experiment on the Pioneer 11 spacecraft. These 'spectral files' retain most of the original telemetry data provided in EDR (Experimenter Data Record) and REDR (Reduced EDR) format but are now archived in ASCII format. The primary data include raw channel counts for energy/charge distributions in instrument units and coordinates. Each file contains a consecutive series of telemetry data readouts for spectra accumulated in various instrument modes. Numbers of records for individual spectra range from six to more than 18,000, so record and file lengths are variable. The data set documentation describes the further processing steps that are required to prepare these data for higher level processing: (1) conversion from Earth Received Time (ERT) to Spacecraft Ephemeris Time (SCET), (2) transformation of spacecraft attitude information to heliocentric (e.g., RTN) coordinates, (3) conversion of raw instrument counts for channels of each energy/charge (E/Q) spectrum to flux units with application of calibration data, and (4) flagging or elimination of bad data and noise. The spectra can then be processed to recover the actual velocity distributions of the incident solar wind plasma and can also be integrated to obtain solar wind bulk parameters such as velocity, density, and temperature. The instrumentation, measured parameters, format of the spectral files, and data processing procedures are fully defined in the text file B3spectralfile.txt. Sample C++ routines are also included to read the spectral files. The document and software files, and a sample data file, can be accessed on-line at:

Alternate Names

  • P-11, Solar Wind Plasma Spectra


  • Space Physics: Heliospheric Studies


  • 73-019A-13L

Additional Information



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



NameRoleOriginal AffiliationE-mail
Dr. Paul R. GazisGeneral ContactNASA Ames Research
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