While the probability is small, it looks like there is the possibility that debris from NASA’s Upper Atmosphere Research Satellite (UARS) could crash to Earth back at its point of origin, the United States. If not there, then another populated part of the Earth’s surface is possible (again a very low probability given how much of the Earth’s surface is water but it is still possible).
According to a fresh update from Harro Zimmer on the seesat-l observers email list, UARS will de-orbit on 24 September at 04:19 UTC +/- 90 minutes (2.19 pm +/- 90 minutes 24 September Australian Eastern Standard Time). According to the prediction made using Mr Zimmers software, UARS at this point will be ascending over 39.55°N, 227.53°E. This will put it over the Pacific, on the way to the United States West Coast then crossing Canada. In his email, he commented that his personal feeling was that it would remain in orbit for one more rotation after that however.
There is a key reason for the change in the likely UARS re-entry time. Solar activity has dropped resulting in the Earth’s upper atmosphere shrinking back to ‘normal’. This has decreased atmospheric drag on UARS, meaning that it will be in orbit for slightly longer than originally expected.
All we can do is watch and wait, plus keep your video cameras handy. Unfortunately, for Australians hoping to see the satellite re-enter there are no upcoming passes of the satellite forecast at all.
