3MS No. 170

Re-entered 12 May 1971

3MS No. 170 (NORAD 5221, COSPAR 1971-042A) was a SU satellite that re-entered Earth's atmosphere on 12 May 1971, launched on 10 May 1971 on the 3MS No. 170 mission. It was operated by IKI / BABTS as part of the 3M programme. The spacecraft was built by NPOL on the Mars bus, with a mass of 4,549 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

years on orbit

4,549

kg mass

Lifecycle

Launched10 May 1971 · on the 3MS No. 170 mission

Operational10 May 1971 · entered service

Retired10 May 1971 · end of operational service

Re-entered12 May 1971 · atmospheric re-entry — object destroyed

Specifications

NORAD ID5221

COSPAR1971-042A

TypeSatellite

OperatorIKI / BABTS

Country / StateSU

ManufacturerNPOL

BusMars

Mass4,549 kg (2,164 kg dry)

Programme3M

CategoryPLAN

OrbitLEO (LLEO/I)

Altitude126 × 191 km

Inclination51.5°

Frequently asked questions

What happened to 3MS No. 170?

3MS No. 170 re-entered Earth's atmosphere on 12 May 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 3MS No. 170 re-enter the atmosphere?

3MS No. 170 re-entered on 12 May 1971, according to Orbital Radar's historical catalogue records.

Who operated and built 3MS No. 170?

3MS No. 170 was operated by IKI / BABTS and built by NPOL (SU).

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

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