Iridium Constellation. Note how the orbits cross each other near the poles

Iridium and Cosmos Satellites Collide!

Some of us have been warning about a catastrophic chain reaction of space collisions that could render near Earth orbits unusable for tens or hundreds of years. Unfortunately, it is very likely that we are going to see a key factor in that scenario tested over the next year: would a collision in one orbit seriously affect satellites in similar orbits but with different inclinations? How about different mean anomalies? (Basically the slot in the orbit each satellite is assigned.) The collision between an Iridium satellite and a Cosmos satellite could act as the test we need to examine this possibility. No one is happy, however. Look to these pages for over the next week as more debris is cataloged to see what is happening!

Jonathan McDowell reports on the amateur satellite observers electronic bulletin board that it was Iridium 33 (ID=24946) and Cosmos 2251 (ID=22675) that collided at 16:56 UTC on the 10th of Feb. 2009.

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The collision took place at about 760 km altitude, one of the most populated altitudes!