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SOLRAD 11A was one of a pair of identical satellites that were placed in a circular equatorial orbit of 20 earth radii. The satellites, which were oriented towards the sun, provided 100 percent real-time, continuous monitoring of solar X-ray, UV, and energetic particle emissions. Experiments included broadband ion chambers observing solar X rays between 0.1 and 60 a, proportional counters and scintillators observing solar X rays between 2 and 150 keV, and EUV detector covering three bands between 170 and 1000 a, a variable resolution Ebert-Fastie spectrometer covering the wavelength range of 1100 to 1600 a (resolution: 1 to 25 a), a solar wind monitor, solar proton, electron, and Alpha particle monitors, two X-ray polarimeters (one utilizing Bragg scattering and the other utilizing Thompson scattering), a Bragg spectrometer observing magnesium-11 and -12 lines, a large-area auroral X-ray detector, and a passively cooled solid-state X-ray detector to measure background X-ray emissions.

Alternate Names

  • 08748
  • NRL-111
  • SESP NO. NRL-111-0264
  • SESP P74-1C
  • SRD-11A

Facts in Brief

Launch Date: 1976-03-15
Launch Vehicle: Titan III-C
Launch Site: Cape Canaveral, United States
Mass: 102.15 kg

Funding Agency

  • Department of Defense-Department of the Navy (United States)


  • Space Physics
  • Solar Physics
  • Astronomy

Additional Information

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



NameRoleOriginal AffiliationE-mail
Capt Ernest W. PeterkinProject ManagerUS Naval Research Laboratory
Mr. Robert W. KreplinProject ScientistUS Naval Research
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