Atmospheric Entry - Uncontrolled and Unprotected Reentries

Uncontrolled and Unprotected Reentries

Of satellites that reenter, approximately 10-40% of the mass of the object is likely to reach the surface of the Earth. On average, about one catalogued object reenters per day.

Due to the Earth's surface being primarily water, most objects that survive reentry land in one of the world's oceans. The estimated chances that a given person will get hit and injured during his/her lifetime is around 1 in a trillion.

In 1978, Cosmos 954 reentered uncontrolled and crashed near Great Slave Lake in the Northwest Territories of Canada. Cosmos 954 was nuclear powered and left radioactive debris near its impact site.

In 1979, Skylab reentered uncontrolled, spreading debris across the Australian Outback, damaging several buildings and killing a cow. The re-entry was a major media event largely due to the Cosmos 954 incident, but not viewed as much as a potential disaster since it did not carry nuclear fuel. The city of Esperance, Western Australia, issued a fine for littering to the United States, which was finally paid 30 years later (not by NASA, but by a privatelly collected funds from radio listeners). NASA had originally hoped to use a Space Shuttle mission to either extend its life or enable a controlled reentry, but delays in the program combined with unexpectedly high solar activity made this impossible.

On February 7, 1991 Salyut 7 underwent uncontrolled reentry with Kosmos 1686. Reentering over Argentina, scattering much of its debris over the town of Capitan Bermudez.