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NASA Space Science Data Coordinated Archive Header



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

Time span: 1977-08-15 to 1979-01-09


These data telemetered from the HEAO A-2 experiment were used to create a primary experiment data base. XRATES, a secondary data base, was created from the primary data base to make scientific data analysis more convenient. The XRATES data base is used primarily to search for possible sources and to examine possible variability of detected sources. Only major frames from the primary data base that are not in engineering format are included. Each XRATES physical record contains data that were accumulated in one major frame except the digital status, which completes a cycle in two major frames, and the analog status, which completes a cycle in eight major frames. Each production XRATES file corresponds to approximately 12 h of data. If no acceptable data exist for a 12-h interval, no XRATES file exists for the interval. Each tape contains about 25 days of XRATES data and no more than 40 files. There are three checks made on the quality of data. A block encoder error indicates a transmission error from the spacecraft to ground. A bit error indicates that one or more bits within a major frame have been improperly received. Fill data indicate that data for that minor frame are missing. This data set consists of magnetic tape blocked by 5048 bytes. Examples of the use of this data base can be found in F.E. Marshall et al., Astrophys. J. Suppl., v. 40, p. 657, 1979; F.E. Marshall et al., Astrophys. J., v. 235, p. 4. 1980.

Alternate Names

  • XRATES Data Base


  • Astronomy: X-Ray


  • 77-075A-02I

Additional Information



Questions and comments about this data collection can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Francis E. MarshallData ProviderNASA Goddard Space Flight
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