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Gamma Ray Observatory, also called Compton gamma-ray observatory


Designation 21225 / 91027B
Launch date 5 Apr 1991
Country of origin United States
Operator NASA
Mission Scientific: Astronomy
Perigee/Apogee 437/462 km
Inclination 28.4°
Period 93.5 min
Launch vehicle STS 37
Mass at launch 15620 kg

The objective of the Compton GRO was to make comprehensive observations of gamma ray sources throughout the Universe. The observatory carried four scientific instruments that made gamma ray energy measurements from 0.1 million electron volts to 30,000 million electron volts.

Orbit reboost maneuver in 1993 extended mission life by 5 years. It recorded over 2600 gamma explosions.

End of life

Out of service Jun 2000
Cause The failure of 1 gyroscope requires the deorbitation of the satellite in order to make sure it will not fall in a populated area. It is too large to completely burn in the atmosphere.
Decay 4 June 2000 06 UT, reentered in the Pacific, approx 4000 km of Hawaii

External resources


sat-index articles

Technical data


Prime contractor TRW
Dimension 7.7 x 5.5 x 4.6 m
Mass at launch 15622 kg
Dry mass 13800 kg
Solar array 21.5 m
Stabilization 3-axis
DC power EOL: 3980 W
Design lifetime 2 years (min)

Realtime acquisition via TDRS (tape recorders have failed).
Telemetry: 2287.5 MHz (realtime: 1/32 kbps, playback: upto 512 kbps)
Command: 2106.4 MHz (1/0.125 kbps)

BATSE (Burst and Transcient Source Experiment)

Payload mass 976 kg
Industrial responsibility Marshall SFC
Gamma-ray energy range 20-600 keV

Equipped with 8 detectors

OSSE (Oriented Scintillation Spectrometer Experiment)

Payload mass 1820 kg
Industrial responsibility Ball Aerospace
Gamma-ray energy range 100 keV-10 MeV

COMTEL (imaging COMpton TELescope)

Payload mass 1460 kg
Industrial responsibility MBB
Gamma-ray energy range 1-30 MeV
Angular resolution 1.7-4.4°

EGRET (Energetic Gamma Ray Experiment Telescope)

Payload mass 1830 kg
Industrial responsibility Goddard SFC
Gamma-ray energy range 20 MeV-30 GeV

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