STP S73-5

Re-entered 26 May 1975

STP S73-5 (NORAD 7499, COSPAR 1974-085C) was a US satellite that re-entered Earth's atmosphere on 26 May 1975, launched on 29 Oct 1974 on the HEXAGON SV-9 mission. It was operated by SAMSO as part of the STP1 programme. The spacecraft was built by BOKT on the S3 bus, with a mass of 193 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.

1974

launched

1975

re-entered

year on orbit

193

kg mass

Lifecycle

Launched29 Oct 1974 · on the HEXAGON SV-9 mission

Operational26 May 1975 · entered service

Retired26 May 1975 · end of operational service

Re-entered26 May 1975 · atmospheric re-entry — object destroyed

Specifications

NORAD ID7499

COSPAR1974-085C

TypeSatellite

OperatorSAMSO

Country / StateUS

ManufacturerBOKT

BusS3

Mass193 kg

ProgrammeSTP1

CategorySCI

OrbitLEO (LEO/S)

Altitude149 × 3,483 km

Inclination97.0°

Frequently asked questions

What happened to STP S73-5?

STP S73-5 re-entered Earth's atmosphere on 26 May 1975, ending a mission that began with its launch in 1974. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did STP S73-5 re-enter the atmosphere?

STP S73-5 re-entered on 26 May 1975, according to Orbital Radar's historical catalogue records.

Who operated and built STP S73-5?

STP S73-5 was operated by SAMSO and built by BOKT (US).

Launched together

HEXAGON SV-9Re-entered 1975 P-11 No. 4429Re-entered 1980

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: HEXAGON SV-9 → What is space debris? →