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Compton Gamma-Ray Observatory (CGRO)

photo of CGRO being released from the Space Shuttle
Credit: NASA

The Compton Gamma-Ray Observatory was launched on April 5, 1991. The second of NASA's great observatories, CGRO has four instruments that cover an unprecedented six orders of magnitude in energy, from 30 keV to 30 GeV. Over this energy range CGRO has an improved sensitivity over previous missions of a full order of magnitude. It operated for almost 9 years and the mission ended on June 4 2000. Unlikely most satellites, CGRO was too large to burn up entirely in the atmosphere during re-entry. To ensure safety on the Earth's surface, NASA redirected the spacecraft into Earth's atmosphere with a controlled re-entry.

Mission Characteristics

* Lifetime: 5 April 1991 - 4 June 2000
* Energy Range: 30 keV - 30 GeV
* Special Features: First Great Gamma-Ray observatory
* Payload:
  • The Burst and Transient Source Experiment (BATSE)
    an all sky monitor 20-1000 keV
  • The Oriented Scintillation Spectrometer Experiment (OSSE)
    0.05-10 MeV energy range
  • The Compton Telescope (Comptel)
    0.8-30 MeV capable of imaging 1 steradian
  • Energetic Gamma Ray Experiment Telescope (EGRET)
    30 MeV-10 GeV
* Science Highlight:
  • The Discovery of an isotropic distribution of the Gamma-ray burst events
  • Mapping the Milky Way using the 26 Al Gamma-ray line
  • Discovery of Blazar Active Galactic Nuclei as primary source of the highest energy cosmic Gamma-rays
  • Discovery of the "Bursting Pulsar"

* Archive: Catalogs, Other products soon available

[Compton Observatory Science Support Center] (

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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Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

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