(NECN: Josh Brogadir, Boston) - The earth is 2/3 ocean, so the chances of the debris coming down somewhere in the water are very likely, but not necessarily the Atlantic Ocean, anywhere close to the coast of Marshfield, MA.
Space junk: it may sound like a punk band, even its name UARS sounds like it could have been a headliner in the 80s.
But the Upper Atmosphere Research Satellite is actually a dead 12,000 pound satellite the size of a bus that had been used to study the ozone layer.
NASA says it has split into a couple dozen huge pieces and that it has slowed down on its descent toward earth.
Thought at first to arrive earlier today, a revised estimate is for arrival from 11pm to 3am, potentially in Africa, Australia, Canada - the only US location, a possibility of Washington state.
But is it a danger to people?
Dr. Susan Heilman of the Museum of Science in Boston says it's extremely improbable.
NASA says it's even unlikely any debris will land in the United States from this largest NASA spacecraft to crash back to Earth, uncontrolled, since 1979.
Still, 26 pieces, the largest of them 300 pounds are expected to hit somewhere - sometime soon.
Dr. Heilman explained that falling space junk has never injured anyone in the space age, so not to worry.
But people we spoke with had it on their minds.
Brian Zolenski told us he thinks there's a concern.
Steve Judkins was at the package store buying "spirits, just in case."
The odds of it hitting anyone?
NASA put the chances at 1-in-3,200.