Bad Astronomy

UARS update 3: new predicted re-entry tonight at 03:16 UTC +/- 5 hrs

[UPDATE to the update (22:00 UTC): a new prediction just came out: tonight, September 23/24, at 04:04 UTC (midnight Eastern US time). The uncertainty is down to +/- 3 hours, and the location is the middle of the Pacific. Clicking the links below to CORDS or the image itself will take you to the most current prediction.]

The Center for Orbital and Reentry Debris Studies has updated their predicted re-entry time for NASA’s UARS satellite. It is now 9/24 (tonight!) at 03:16 UTC, which puts it over the Sahara:

Note that again this is later than the last estimate. As the satellite has gotten lower, aerodynamic drag – the wind blowing on it, tenuous as it is – has changed its orientation, creating less drag, slowing the descent.

Please note that the time is still uncertain, though now it’s only +/- 5 hours. Still, that’s a wide swath of Earth in that range, so we’re still not sure where it’ll burn up.

Check the Related posts links below for more info on the satellite, why it’s coming down, and how to read that map. Again, the danger from this is pretty minimal. You may note that the three predictions we’ve had have put re-entry over the ocean or otherwise largely uninhabited areas, and that’s not a coincidence: most of the Earth is like that! That’s why the odds of someone getting hit are so low.

I’m sure we’ll get another update or two in the next few hours, so stay tuned. You can also check the CORDS site for updates, and the NASA page as well.

Related posts:

- UARS update 2: new predicted re-entry at 00:58 UTC
- Update: satellite *might* fall on Friday at 22:00 UTC +/- 9 hours
- NASA satellite due to burn up some time in the next few days