NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Pioneer 11 Solar Wind Plasma Data Archive


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

Time span: 1973-04-21 to 1992-05-30


This data set consists of a group of document and data files for the final archive of full (summary) and hourly resolution data from the Pioneer 11 Plasma Analyzer. Spacecraft attitude and trajectory data files are also included, the latter not being considered definitive (refer to NSSDC Dataset 73-019A-00G for definitive ephermeris) but otherwise useful for heliospheric studies. The plasma bulk parameters (bulk velocity, proton number density, proton temperature, and flow angles) were obtained using one of three processing schemes described in the data set documentation. Hourly averaged data files were created by averaging every valid parameter in each hour, regardless of the processing scheme used to derive it. Individual points in the Summary (high resolution) data set are flagged with a 'data quality index' (BADREC) that indicates the reliability of each point as described in the data set description. All *.DAT files are written in VAX binary format. Version 2.3 of this data set includes data reprocessed by NASA Ames from April 1973 through the most recent data. Earlier data set versions should be discarded. The Pioneer 10 and 11 data production software has been tested by examining its response to a range of simulated plasma distributions. These tests suggest that the plasma parameters measured by Pioneer 10 and 11 may have the following uncertainties: bulk velocity less than five km/sec, proton number density - 20%, proton temperature - 20% for T greater than 10,000 K and 40% for 10,000 K > T > 5,000 K. Flow angle calibration is uncertain but probably less than five degrees prior to 1983 and unreliable at Pioneer 10 after 1983. The data set components are encapsulated in an SFDU structure including the data files in VAX binary format and the following document text files: VOLDESC file for the overall data set, and individual FORMAT files for the four data types (summary plasma, hourly plasma, spacecraft attitude, and spacecraft trajectory). The FORMAT files define the data field formats and also include sample FORTRAN source routines to output selected parameters into ASCII files. The additional files *.FOR and *.EXE include the extracted source files and the executables for each of the four routines. The complete data set is accessible on-line via the COHO.PIONEER11.PLASMA.VERSION23 directory of the anonymous FTP site under VMS at

Alternate Names

  • P-11, Solar Wind Plasma Archive


  • Space Physics: Heliospheric Studies


  • 73-019A-13K

Additional Information



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



NameRoleOriginal AffiliationE-mail
Dr. Aaron BarnesData ProviderNASA Ames Research Center
Dr. Paul R. GazisGeneral ContactNASA Ames Research
[] NASA Logo -