I2P No. 503

Re-entered 4 Apr 1971

I2P No. 503 (NORAD 5113, COSPAR 1971-027A) was a SU satellite that re-entered Earth's atmosphere on 4 Apr 1971, launched on 4 Apr 1971 on the I2P mission. It was operated by PKO as part of the IS 5V91T programme. The spacecraft was built by TSKBM/KB1 on the IS bus, with a mass of 1,400 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

1,400

kg mass

Lifecycle

Launched4 Apr 1971 · on the I2P mission

Operational4 Apr 1971 · entered service

Retired4 Apr 1971 · end of operational service

Re-entered4 Apr 1971 · atmospheric re-entry — object destroyed

Specifications

NORAD ID5113

COSPAR1971-027A

TypeSatellite

OperatorPKO

Country / StateSU

ManufacturerTSKBM/KB1

BusIS

Mass1,400 kg

ProgrammeIS 5V91T

CategoryWEAPON

OrbitLEO (LEO/I)

Altitude801 × 1,009 km

Inclination65.7°

Frequently asked questions

What happened to I2P No. 503?

I2P No. 503 re-entered Earth's atmosphere on 4 Apr 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 I2P No. 503 re-enter the atmosphere?

I2P No. 503 re-entered on 4 Apr 1971, according to Orbital Radar's historical catalogue records.

Who operated and built I2P No. 503?

I2P No. 503 was operated by PKO and built by TSKBM/KB1 (SU).

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

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