Thursday, Sep 10, 2026 The claims desk. Receipts included. POWERED BY LENZ ↗
IsThis

The 2009 Kosmos 2251–Iridium 33 collision near 790 km created about 2,000 trackable debris fragments.

The Claim

In 2009, the defunct Russian satellite Kosmos 2251 collided with the active U.S. satellite Iridium 33 at an altitude of about 790 km, generating about 2,000 debris fragments, many of which remain in orbit.

Verified by Lenz ·

The Short Version

The core facts are well supported by authoritative space-agency and peer-reviewed sources. Kosmos 2251 and Iridium 33 collided in 2009 at roughly the 780–800 km band, commonly reported near 789–790 km, and the event produced on the order of 2,000 trackable debris fragments. A substantial number remained in orbit for many years afterward.

Caveats

  • Exact altitude varies across reputable sources, with figures ranging from about 776 km to about 790 km.
  • Debris totals depend on when the count was made and what size threshold was tracked; early counts were lower and later catalog totals exceeded 2,000.
  • The number still in orbit changes over time, so current remaining-fragment counts should not be confused with the total produced by the collision.

The Receipts

  1. The Collision of Iridium 33 and Cosmos 2251: The Shape of Things to Come

    NASA Technical Reports Server (NTRS)

  2. About space debris

    European Space Agency (ESA)

  3. Iridium 33/Cosmos 2251 Collision and its Implications for Space Operations

    UNOOSA (United Nations Office for Outer Space Affairs) / NASA

  4. COSMOS 2251

    NASA Goddard Space Flight Center (NSSDC)

  5. Quarterly News, Volume 13, Issue 3 (Iridium 33/Cosmos 2251 collision coverage)

    NASA Orbital Debris Program Office

  6. Analysis of Debris from the Collision of the Cosmos 2251 and the Iridium 33 Satellites

    Science and Global Security (peer‑reviewed journal)

  7. Space Surveillance: Lessons Learned From The Iridium Cosmos Collision

    AGI (Analytical Graphics Inc.) / space-surveillance paper

  8. Frequently Asked Questions - Orbital Debris Program Office

    NASA Orbital Debris Program Office

  9. Analysis of the Iridium 33-Cosmos 2251 Collision

    CelesTrak

  10. Satellites collide in space; debris a risk

    Reuters

+ 14 more sources — see the full list on Lenz

Filed Under

Iridium 33Kosmos 2251Russian EmpireUnited States

More Fact Checks