🛰️ ROCKET BODY · HISTORICAL RECORD
Blok-2BL 55-639
Historical recordBlok-2BL 55-639 (NORAD 12311, COSPAR 1981-016E) is a historical SU catalogue entry no longer tracked in the live catalogue, launched on 19 Feb 1981 on the Oko mission. It is catalogued as Blok-2BL No. 71655-639. It was operated by RVSN. The spacecraft was built by NPOE on the Blok-L bus, with a mass of 4,500 kg. Historical record from Orbital Radar's satellite archive, cross-referenced with the live satellite catalogue.
1981
launched
45
years on orbit
4,500
kg mass
Lifecycle
Launched19 Feb 1981 · on the Oko mission
Specifications
NORAD ID12311
COSPAR1981-016E
TypeRocket body
OperatorRVSN
Country / StateSU
ManufacturerNPOE
BusBlok-L
Mass4,500 kg (1,000 kg dry)
OrbitHEO (HEO/M)
Altitude664 × 38,986 km
Inclination63.0°
Frequently asked questions
What happened to Blok-2BL 55-639?
Blok-2BL 55-639 is a historical catalogue entry from a 1981 launch. It is not currently tracked in the live catalogue — typically meaning it has decayed, been retired, or its tracking elements have lapsed.
Who operated and built Blok-2BL 55-639?
Blok-2BL 55-639 was operated by RVSN and built by NPOE (SU).
Launched together
Historical record from the Orbital Radar satellite archive. Sources & methodology: data sources. Accessed 2026-10-15.