NASA says the UARS satellite will hurtle toward us at 5 miles per second, and there's no way of telling right now of where it will land.
It was in Sept. 1991 that the space shuttle Discovery took the satellite into orbit to help scientists better understand Earth's climate. 20 years later, it's coming back in a most unhelpful manner.
The doomed spacecraft is a monster, a 6.5-ton chunk of metal the size of a bus, plunging toward Earth.
The UARS could come crashing down as early as next Sunday. NASA says it won't know for sure where it will hit until just before it enters the atmosphere, moving at a speed of 18,000 mph- too fast to give anybody time to get out of the way.
The possible target range is basically everywhere people live, between 57 degrees north, and 57 degrees south.
"Fifty-seven north and 57 south pretty much encompasses the entire populated world," said NASA scientist Dr. Nick Johnson. "There is a small percent live above or below those latitudes. But the vast majority, the 7 billion people on the planet, lives within those latitudes."
NASA says most of the satellite will burn up as it re-enters the atmosphere, but that 26 pieces, totaling more than 1,000 pounds, will make it to the ground somewhere.
The chances of a person getting hit?
"Is on the order of one in 3,200," said Johnson.
Compare that with your chance of being struck by lightning in a given year- about one in a million.
NASA says it will have about two hours to issue warnings of where the satellite debris will likely hit once the satellite enters Earth's atmosphere.
NASA also says that the risk to public safety is very small, and that since the start of the space age in the 1950s there have been no injuries from re-entering space objects.