spacetoday.net: UARS expected to reenter late this week

Posted: Tue, Sep 20, 2011, 8:51 AM ET (1251 GMT)
UARS illustration (NASA)

NASA is predicting that a 20-year-old satellite will reenter the Earth's atmosphere on Friday, posing a very small but non-zero risk to the public. The Upper Atmosphere Research Satellite (UARS), launched by the space shuttle in 1991, is in a decaying orbit as atmospheric drag slows down the spacecraft and lowers its orbit at an accelerating rate. As of late Monday NASA predicted the spacecraft would reenter the atmosphere on Friday, give or take a day. The satellite's orbital inclination of 57 degrees means it passes over most populated regions of the Earth. NASA expects that 26 pieces of the satellite, with a combined mass of 532 kilograms, will survive reentry and reach the surface. NASA has estimated that there is a 1-in-3,200 chance that debris from the satellite would injure anyone, with the most likely outcome that the debris falls in the ocean.