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🛰️ SATELLITE · HISTORICAL RECORD

Gamma Ray Observatory

Re-entered 7 Apr 1991

Gamma Ray Observatory (NORAD 21225, COSPAR 1991-027B) was a US satellite that re-entered Earth's atmosphere on 7 Apr 1991, launched on 5 Apr 1991 on the OV-104 LEO deploy mission. It was operated by GSFC as part of the Great Obs programme. The spacecraft was built by TRW on the GRO bus, with a mass of 15,622 kg. Like most satellites in low orbits, it was gradually slowed by atmospheric drag until re-entry. Historical record from Orbital Radar's satellite archive, cross-referenced with the live satellite catalogue.

1991
launched
1991
re-entered
0
years on orbit
15,622
kg mass

Lifecycle

Launched5 Apr 1991 · on the OV-104 LEO deploy mission
Operational4 Jun 2000 · entered service
Retired4 Jun 2000 · end of operational service
Re-entered7 Apr 1991 · atmospheric re-entry — object destroyed

Specifications

NORAD ID21225
COSPAR1991-027B
TypeSatellite
OperatorGSFC
Country / StateUS
ManufacturerTRW
BusGRO
Mass15,622 kg (13,891 kg dry)
ProgrammeGreat Obs
CategoryAST
OrbitLEO (LLEO/I)
Altitude441 × 455 km
Inclination28.5°

Frequently asked questions

What happened to Gamma Ray Observatory?

Gamma Ray Observatory re-entered Earth's atmosphere on 7 Apr 1991, ending a mission that began with its launch in 1991. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did Gamma Ray Observatory re-enter the atmosphere?

Gamma Ray Observatory re-entered on 7 Apr 1991, according to Orbital Radar's historical catalogue records.

Who operated and built Gamma Ray Observatory?

Gamma Ray Observatory was operated by GSFC and built by TRW (US).

Launched together

OV-104Re-entered 1991
Historical record from the Orbital Radar satellite archive. Sources & methodology: data sources. Accessed 2026-09-06.