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🛰️ SATELLITE · HISTORICAL RECORD

HEOS A1

Re-entered 6 Dec 1968

HEOS A1 (NORAD 3595, COSPAR 1968-109A) was a I-ESRO satellite that re-entered Earth's atmosphere on 6 Dec 1968, launched on 5 Dec 1968 on the HEOS A1 mission. It was operated by ESRO as part of the HEOS programme. The spacecraft was built by JUNK on the HEOS bus, with a mass of 99 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.

1968
launched
1968
re-entered
0
years on orbit
99
kg mass

Lifecycle

Launched5 Dec 1968 · on the HEOS A1 mission
Operational28 Oct 1975 · entered service
Retired28 Oct 1975 · end of operational service
Re-entered6 Dec 1968 · atmospheric re-entry — object destroyed

Specifications

NORAD ID3595
COSPAR1968-109A
TypeSatellite
OperatorESRO
Country / StateI-ESRO
ManufacturerJUNK
BusHEOS
Mass99 kg
ProgrammeHEOS
CategorySCI
OrbitLEO (DSO)
Altitude12,244 × 210,550 km
Inclination52.6°

Frequently asked questions

What happened to HEOS A1?

HEOS A1 re-entered Earth's atmosphere on 6 Dec 1968, ending a mission that began with its launch in 1968. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did HEOS A1 re-enter the atmosphere?

HEOS A1 re-entered on 6 Dec 1968, according to Orbital Radar's historical catalogue records.

Who operated and built HEOS A1?

HEOS A1 was operated by ESRO and built by JUNK (I-ESRO).

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