UARS RE-ENTRY

RE-ENTRY ALERT: NASA's UARS satellite is making its final orbits around Earth, tumbling and flashing brightly as it descends toward a Sept. 23rd re-entry. Amateur astronomer Jim Saueressig II caught the bus-sized satellite flying over Burlington, Kansas, on Sept. 20th (image). "It was easily visible in spite of the moonlight and the twilight of the sunrise. The tumble and associated flares were very apparent," he says.

Satellite tracking expert Ted Molczan has used USSTRATCOM's orbital elements of UARS to predict a decay time "late on Sep 23, roughly between 18:00 and 22:00 UTC." Click on the map to view ground tracks corresponding to this interval:

There is still potential for the estimated time of decay to shift somewhat before it begins to narrow down," cautions Molczan.

The disintegration of UARS is expected to produce a fireball that could be visible even in broad daylight. Not all of the spacecraft will burn up in the atmosphere, however; according to a NASA risk assessment, as many as 26 potentially hazardous pieces of debris could be scattered along a ground track some 500 miles long. The same report puts the odds of a human casualty at 1 in 3200.

For last-chance sightings of this brightly flashing satellite, please check the Simple Satellite Tracker or download the Satellite Flybys app for your smartphone.