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🛰️ SATELLITE · HISTORICAL RECORD

IMP G

Re-entered 22 Jun 1969

IMP G (NORAD 3990, COSPAR 1969-053A) was a US satellite that re-entered Earth's atmosphere on 22 Jun 1969, launched on 21 Jun 1969 on the IMP G mission. It was operated by GSFC as part of the IMP programme. The spacecraft was built by GSFC on the IMP bus, with a mass of 79 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.

1969
launched
1969
re-entered
0
years on orbit
79
kg mass

Lifecycle

Launched21 Jun 1969 · on the IMP G mission
Operational23 Dec 1972 · entered service
Retired23 Dec 1972 · end of operational service
Re-entered22 Jun 1969 · atmospheric re-entry — object destroyed

Specifications

NORAD ID3990
COSPAR1969-053A
TypeSatellite
OperatorGSFC
Country / StateUS
ManufacturerGSFC
BusIMP
Mass79 kg
ProgrammeIMP
CategorySCI
OrbitLEO (DSO)
Altitude640 × 176,219 km
Inclination87.1°

Frequently asked questions

What happened to IMP G?

IMP G re-entered Earth's atmosphere on 22 Jun 1969, ending a mission that began with its launch in 1969. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did IMP G re-enter the atmosphere?

IMP G re-entered on 22 Jun 1969, according to Orbital Radar's historical catalogue records.

Who operated and built IMP G?

IMP G was operated by GSFC and built by GSFC (US).

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