Solar Mesosphere Explorer

Re-entered 5 Mar 1991

Solar Mesosphere Explorer (NORAD 12887, COSPAR 1981-100A) was a US satellite that re-entered Earth's atmosphere on 5 Mar 1991, launched on 6 Oct 1981 on the Solar Mesosphere Explore mission. It was operated by JPL / CLASP as part of the DeltaEx programme. The spacecraft was built by BALL on the SME bus, with a mass of 437 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.

1981

launched

1991

re-entered

years on orbit

437

kg mass

Lifecycle

Launched6 Oct 1981 · on the Solar Mesosphere Explore mission

Operational15 Dec 1986 · entered service

Retired15 Dec 1986 · end of operational service

Re-entered5 Mar 1991 · atmospheric re-entry — object destroyed

Specifications

NORAD ID12887

COSPAR1981-100A

TypeSatellite

OperatorJPL / CLASP

Country / StateUS

ManufacturerBALL

BusSME

Mass437 kg

ProgrammeDeltaEx

CategoryEOSCI

OrbitLEO (LLEO/S)

Altitude481 × 486 km

Inclination97.7°

Frequently asked questions

What happened to Solar Mesosphere Explorer?

Solar Mesosphere Explorer re-entered Earth's atmosphere on 5 Mar 1991, ending a mission that began with its launch in 1981. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did Solar Mesosphere Explorer re-enter the atmosphere?

Solar Mesosphere Explorer re-entered on 5 Mar 1991, according to Orbital Radar's historical catalogue records.

Who operated and built Solar Mesosphere Explorer?

Solar Mesosphere Explorer was operated by JPL / CLASP and built by BALL (US).

Launched together

UoSAT 1Re-entered 1989

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

Browse the live satellite directory → Re-entered satellites archive → Launch record: Solar Mesosphere Explore → What is space debris? →