Thursday, September 22, 2011
So the UARS satellite will reenter Friday. The potential debris zone was announced, unhelpfully as "from Newfoundland to Argentine." Now, your personal chance of getting killed by it are about 1 in 21 trillion. (No one has ever been killed by space debris. Accounts of people killed by natural debris (meteorites) are disputed, although it's probably happened.) This event does highlight the need for better rules about end-of-life/disposal mechanisms on all spacecraft. We have put thousands of tons of stuff in orbit and don't have a good handle on how to clear it out or deorbit it safely, although schemes ranging from deployable cone-shaped Mylar(TM) drag-inducers to microsatellites that will hunt down large spacecraft and use their own thrusters to steer them into the atmosphere or up into disposal orbits have been proposed.