(Reuters) - A defunct NASA science satellite is expected to fall back to Earth on Friday, showering debris somewhere on the planet although scientists cannot predict exactly where, officials said.
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The largest chunk of wreckage from UARS is expected to be about 331 pounds (151 kg), says Nicholas Johnson, chief scientist of NASA's Orbital Debris Program office at the Johnson Space Center in Houston.

As of Sunday, UARS was in a 133-mile by 149-mile (215-km by 240-km) high orbit around Earth. Re-entry is expected some time on Friday, although it could happen as early as Thursday or as late as Saturday.

http://www.reuters.com/article/2011/...78I5GE20110919