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🛰️ SATELLITE · HISTORICAL RECORD

IMP I

Re-entered 14 Mar 1971

IMP I (NORAD 5043, COSPAR 1971-019A) was a US satellite that re-entered Earth's atmosphere on 14 Mar 1971, launched on 13 Mar 1971 on the IMP I 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 288 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.

1971
launched
1971
re-entered
0
years on orbit
288
kg mass

Lifecycle

Launched13 Mar 1971 · on the IMP I mission
Operational2 Oct 1974 · entered service
Retired2 Oct 1974 · end of operational service
Re-entered14 Mar 1971 · atmospheric re-entry — object destroyed

Specifications

NORAD ID5043
COSPAR1971-019A
TypeSatellite
OperatorGSFC
Country / StateUS
ManufacturerGSFC
BusIMP
Mass288 kg (276 kg dry)
ProgrammeIMP
CategorySCI
OrbitLEO (DSO)
Altitude1,569 × 203,825 km
Inclination30.2°

Frequently asked questions

What happened to IMP I?

IMP I re-entered Earth's atmosphere on 14 Mar 1971, ending a mission that began with its launch in 1971. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did IMP I re-enter the atmosphere?

IMP I re-entered on 14 Mar 1971, according to Orbital Radar's historical catalogue records.

Who operated and built IMP I?

IMP I 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.