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The OSO-7 Satellite

photo of OSO-7
Credit: NASA

OSO-7, like the other Orbiting Solar Observatory missions, was primarily a solar observatory designed to point a battery of UV and X-ray telescopes at the Sun from a platform mounted on a cylindrical wheel. The detectors for observing cosmic X-ray sources were the X-ray proportional counters, built by MIT, the hard X-ray telescope by UC San Diego and the Gamma Ray Monitor by the University of New Hampshire.

Mission Characteristics

* Lifetime: 29 September 1971 - 9 July 1974
* Energy Range: 1 keV - 10 MeV
* Payload:
  • 2 banks of Proportional Counters: 1 - 60 keV, FOV 1° & 3°
  • Hard X-ray telescope: 7 - 550 keV, FOV 6.5°, effective area ~64 cm2
  • Gamma ray Monitor: 300 keV - 10 MeV, resolution 7.8% at 662 keV
* Science Highlights:
  • X-ray All-sky survey
  • Discovery of the 9-day periodicity in Vela X-1 which led to its optical identification as a HMXRB.
  • Gamma-ray observations of solar flares
* Archive: No data available at the HEASARC.
NSSDC ( holds the OSO-7 data in their native format.
[About OSO-7] ( [Gallery] ( [Publications] (

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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All material on this site has been created and updated between 1997-2012.

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