NASA Defunct Satellite: Where Did it Really Fall?

Those worried about getting hit by NASA's defunct Upper Atmosphere Research Satellite (UARS) can breathe a sigh of relief. The satellite fell into the Pacific Ocean sometime between 11:23pm Friday and 1:09am Eastern Saturday morning, Sept 23.

The 6-ton satellite was predicted to break apart above Canada or Africa, but recent reports put the derby somewhere in the Pacific Ocean, though NASA scientists aren't exactly sure where.

26 pieces of the satellite were predicted to survive reentry.

Best estimates put the downed wreckage somewhere roughly 1,000 miles north of Honolulu, around the Christmas Island. Though NASA says there are no reports of anyone witnessing the satellite decent into the Earth's atmosphere, according to Nick Johnson, NASA's chief scientist for orbital debris.

Some may wonder why NASA was unable to track the satellite, since it has a global radar system designed to track ballistic missile heading to the U.S. But there are a number of differences between a ballistic missile and a satellite plummeting to Earth.

This was not an easy re-entry to predict because of the natural forces acting on the satellite as its orbit decayed, Johnson said in a NASA statement.

UARS launched in 1991 and was the first multi-instrumented satellite designed to study the chemical composition of Earth's atmosphere. It also provided much data on the amount of light that comes from the sun in the ultraviolet and visible wavelengths. In 2005 the satellite reached the end of its scientific career as it was content to float in Earth's upper atmosphere until last Saturday.

Though the threat of falling space junk has yet to pass. Another dead satellite is due to fall to Earth this coming November. The German Aerospace Center says the decommissioned X-ray observatory, ROSAT, will exit orbit soon. Though it has yet been able to calculate where the 2.4-ton satellite will fall.

Those worried about being struck by space debris should put their fears to rest. NASA puts the chances that someone, anyone, would be harmed by the falling space junk at 1-in-3,200. And the chance that you personally would be hit by a piece of falling satellite is at 1-in-22 trillion, given that there are 7 billion Earthlings.