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The Small Astronomy Satellite 2 (SAS-2)

photo of SAS-2
Credit: NASA

The second NASA Small Astronomy Satellite (SAS-2) was dedicated to gamma-ray astronomy in the energy range above 35 MeV. SAS-2 was launched on 1972 November 15 and began operations on 1972 November 19. On 1973 June 8, a failure of the low-voltage power supply ended the collection of data.

Mission Characteristics

* Lifetime: 19 November 1972 - 8 June 1973
* Energy Range: 20 MeV - 1 GeV
* Payload:
  • 32-level wire spark-chamber aligned with satellite spin axis (20 MeV-1 GeV), eff. area 540 cm2
* Science Highlights:
  • The first detailed look at the gamma-ray sky.
  • Established the high energy component of diffuse celestial radiation.
  • Correlated the gamma-ray background with galactic structural features.
* Archive: Raw data, image and exposure maps

[About SAS-2] ( [Archive] ( [Gallery] ( [Publications] (

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