Plummeting US Satellite to Hit Earth Friday

NASA launched the Upper Atmosphere Research Satellite (UARS) 20 years ago this month. And now that bus-sized satellite is plunging toward Earth.

Mark Matney, an orbital debris scientist at NASA's Johnson Space Center in Texas, says UARS will likely reenter the atmosphere on September 23, 2011. He says scientists will be able to narrow the time frame as it gets closer.