This artist's conceptual image provided by NASA shows the Upper Atmosphere Research Satellite, or UARS.
This artist's conceptual image provided by NASA shows the Upper Atmosphere Research Satellite, or UARS. NASA
It looks like a giant piece of biscotti covered with gold foil and pipe cleaners. But it's really a decommissioned weather satellite the size of a bus that NASA says will probably fall to Earth by Friday, oh, give or take a day.
Most of the Upper Atmosphere Research Satellite (or UARS) will burn up as the spacecraft plunges into the lower atmosphere, but some pieces may survive and strike the ground nearly anywhere between 57 north latitude and 57 south latitude. That's pretty much anywhere on the continents and oceans. Antarctica appears to be safe.
In its risk assessment, NASA says the possibility of somebody getting hit by something is small, but it estimates 26 "potentially hazardous objects" from the UARS may survive the flaming return, and not all of them will be lightweight.
Washington Post blogger Joel Achebloch says this is the biggest piece of space debris to come back to earth in 30 years and it should create a big light show. If only they knew where to look. This week, NASA will start offering daily briefings on the satellite's position.
The bloggers at Space.com remind everyone that most of the Earth is covered with water, so chances are greater that space debris will plunge into an ocean. It's hard to predict where and when, because the UARS's orbit is falling a lot faster than people expected. Solar activity is blamed. This warms up the atmosphere and increases drag on the satellite, cutting its flight shorter.
NASA says the UARS blasted into space in 1991 aboard the space shuttle Discovery. It aided scientists studying the Earth's ozone layer, and other aspects of the planet's upper atmosphere. (HT: Bill Chappell)