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This NRL satellite was one of the SOLRAD series that began in 1960 to provide continuous coverage of solar radiation with a set of standard photometers. SOLRAD 9 was a spin-stabilized satellite oriented with its spin axis perpendicular to the sun-satellite line so that the 14 solar X-ray and UV photometers pointing radially outward from its equatorial belt viewed the sun with each revolution. Data were simultaneously transmitted via FM/AM telemetry and recorded in a core memory that read out its contents on command. Individual scientists and institutions were invited to receive and use the data transmitted on the 136-MHz telemetry band on the standard IRIG channels 3 through 8. For the period July 1971 to June 1973, the core memory data of SOLRAD 10 were used rather than those from SOLRAD 9. The SOLRAD 10 core memory failed June 11, 1973, and SOLRAD 9 was heavily used until February 25, 1974, when the gas supply of the attitude control system was exhausted. Lacking attitude control, SOLRAD 9 was operationally useless and was turned off. For more details, see R. W. Kreplin and D. M. Horan, "The NRL SOLRAD 9 Satellite Solar Explorer B 1968-17A," NRL Report 6800, 1969.

Alternate Names

  • 03141
  • Explorer 37

Facts in Brief

Launch Date: 1968-03-05
Launch Vehicle: Scout
Launch Site: Wallops Island, United States
Mass: 198 kg

Funding Agencies

  • NASA-Office of Space Science Applications (United States)
  • Department of Defense-Department of the Navy (United States)


  • Solar Physics

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Mr. John R. HoltzProgram ManagerNASA Headquarters
Mr. Robert W. KreplinProject ManagerUS Naval Research
Dr. Goetz K. OertelProgram ScientistNASA Headquarters
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