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🛰️ SATELLITE · HISTORICAL RECORD

Explorer 1 Prime Unit 2

Re-entered 30 Jun 2024

Explorer 1 Prime Unit 2 (NORAD 37855, COSPAR 2011-061F) was a US satellite that re-entered Earth's atmosphere on 30 Jun 2024, launched on 28 Oct 2011 on the NPOESS Prep Project mission. It was operated by MSU as part of the MSU programme. The spacecraft was built by MSU on the Cubesat 1U bus, with a mass of 1 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.

2011
launched
2024
re-entered
13
years on orbit
1
kg mass

Lifecycle

Launched28 Oct 2011 · on the NPOESS Prep Project mission
Operational1 Jun 2024 · entered service
Retired1 Jun 2024 · end of operational service
Re-entered30 Jun 2024 · atmospheric re-entry — object destroyed

Specifications

NORAD ID37855
COSPAR2011-061F
TypeSatellite
OperatorMSU
Country / StateUS
ManufacturerMSU
BusCubesat 1U
Mass1 kg
ProgrammeMSU
CategorySCI
OrbitLEO (LEO/S)
Altitude458 × 815 km
Inclination101.7°

Frequently asked questions

What happened to Explorer 1 Prime Unit 2?

Explorer 1 Prime Unit 2 re-entered Earth's atmosphere on 30 Jun 2024, ending a mission that began with its launch in 2011. Objects in low orbits are gradually slowed by atmospheric drag until they fall back and burn up on re-entry.

When did Explorer 1 Prime Unit 2 re-enter the atmosphere?

Explorer 1 Prime Unit 2 re-entered on 30 Jun 2024, according to Orbital Radar's historical catalogue records.

Who operated and built Explorer 1 Prime Unit 2?

Explorer 1 Prime Unit 2 was operated by MSU and built by MSU (US).

Launched together

NPOESS Prep ProjectNORAD 37849DICE-1Re-entered 2024DICE-2Re-entered 2024Radio Aurora ExplorerRe-entered 2024AubieSat-1Re-entered 2024
Historical record from the Orbital Radar satellite archive. Sources & methodology: data sources. Accessed 2026-09-06.