🛰️ SATELLITE · HISTORICAL RECORD
DSP 4
Retired 2018DSP 4 (NORAD 5851, COSPAR 1972-010A) is a retired US satellite, withdrawn from service around 8 Jan 2018, launched on 1 Mar 1972 on the DSP 4 mission. It was operated by SAMSO as part of the DSP I programme. The spacecraft was built by TRW on the DSP bus, with a mass of 903 kg. Historical record from Orbital Radar's satellite archive, cross-referenced with the live satellite catalogue.
1972
launched
2018
retired
54
years on orbit
903
kg mass
Lifecycle
Launched1 Mar 1972 · on the DSP 4 mission
Operational3 Aug 1981 · entered service
Retired8 Jan 2018 · end of operational service
StatusOn orbit (not live-tracked)
Specifications
NORAD ID5851
COSPAR1972-010A
TypeSatellite
OperatorSAMSO
Country / StateUS
ManufacturerTRW
BusDSP
Mass903 kg (860 kg dry)
ProgrammeDSP I
CategoryEW
OrbitGEO (GEO/I)
Altitude35,692 × 35,881 km
Inclination5.7°
Frequently asked questions
What happened to DSP 4?
DSP 4 was retired from service around 8 Jan 2018 after launching in 1972. It is no longer operational but remains catalogued.
How long was DSP 4 operational?
DSP 4 was operational for roughly 36 years, from 3 Aug 1981 to 8 Jan 2018.
Who operated and built DSP 4?
DSP 4 was operated by SAMSO and built by TRW (US).
Historical record from the Orbital Radar satellite archive. Sources & methodology: data sources. Accessed 2026-09-06.