Why we won't have to worry when the Int'l Space Station crashes

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Dec 15, 2012

On Friday, NASA's six-ton Upper Atmosphere Research Satellite (UARS) descended from orbit and broke apart on re-entry, spreading debris across 500 miles. That satellite was about the size of a bus. So what will happen when the football-field-sized International Space Station (ISS) deorbits?

If you're asking that question, you're not the only one: NASA is starting to formulate answers, even though the ISS is still in service and will be until 2020 (perhaps 2028). But the 431-ton structure—which, if you do the math, is over 71 times larger than UARS—needs a great deal of planning to be brought down safely.

But anyone who fears a shower of metal falling down at hundreds of miles per hour should note that UARS was an uncontrolled re-entry; the ISS's descent will be controlled at every step ... as has been the plan since it was placed 240 miles straight up.

Kirk Shireman, deputy manager of NASA's space station program, told MSNBC that the re-entry will be done in stages.

First, the space station, which requires periodic boosts, will be allowed to decay from orbit naturally. Next:

They'll also dock one or more unmanned spacecraft to the station then, to get ready for future deorbit burns. The station is so massive that it'll need some help to make these maneuvers ...

Before the station circles too low, its crew will be evacuated. When the space station gets down to about 115 miles above the Earth, engineers will perform a series of deorbit burns with the docked vehicle(s) to take it even lower, Shireman explained.

One final burn will send the gigantic structure tumbling toward Earth's atmosphere, hopefully over a wide-open stretch of ocean.

This isn't the first time a large structure will have been deorbited: The Russian space station Mir, which weighed in at 250 tons, was brought down in three stages in 2001. The debris fell into the Pacific Ocean outside of Fiji and caused no injury or damage.

On the other hand, the Skylab space station, which was in use from 1973 to 1979, suffered from a calculation error that caused debris to fall near Perth, Australia. (Sidenote: The United States never did pay a littering fine.)

NASA plans to devote an entire year before the ISS will be brought down to the problem of a controlled deorbit, so the chances of being hit by a random space toilet (like what happened to our protagonist George in the show Dead Like Me) are slim.

But let's be honest—being taken out by some random piece of the International Space Station would be an awesome way to go.

(via MSNBC)