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NASA is providing very brief updates on the reentry of the UARS satellite. They also published an extensive study of the Re-entry and risk assessment for the NASA Upper Atmosphere Research Satellite (UARS)

The Planetary Society Blog has some nice coverage and a graph of altitude over time: Keeping track of UARS' reentry

The well-known satellite tracking site Heavens Above site provides UARS - Visible Passes data which seems relatively up-to-date, but without information on the uncertainty.

What I want is actual tabular historical data, e.g. the changes in the Orbital elements over the last months, weeks or days of its flight, and a characterization of how those elements other than altitude change over time.

Update: The Center for Orbital and Reentry Debris Studies has a prediction and map for UARS orbits.

Update 2: One authoritative source is Space-Track, run by United States Strategic Command (USSTRATCOM), but you need to be an "approved registered user"....

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closed as off topic by Waffle's Crazy Peanut, Manishearth Dec 29 '12 at 8:44

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This would probably be better suited to the Space Exploration proposal, as this isn't a space observing telescope, and even if it was, it has nothing to do with astronomy (heliophysics or ITM, maybe, but when I think prototypical astronomy questions, those aren't in it). This would even be better in the physics site, but even that's pushing it. – Joe Sep 27 '11 at 0:03
And when you're searching for this type of data, the relevent term is 'ephemeris' or 'ephemerides'. You can also try 'spice kernels', which refers to a specific format used by the SPICE toolkit. – Joe Sep 27 '11 at 0:07
@Joe thanks for the link to Space Exploration. It doesn't seem very far along yet, not sure if it will fly. The faq for Astronomy is pretty vague about what is on-topic, and I know there are lots of planetary astronomers and astrophysicists interested in orbit dynamics. Given the stats for this site at, I'd say more relevant questions would really help us get out of beta - we need 15/day, and only have 2/day now. – nealmcb Jan 15 '12 at 16:27

Update 2: I applied for, and quickly received, authorization for an account at Space-Track, as an amateur observer. They let you download up to the 10 most recent TLEs for most satellites, and have alerts for reentries etc.

Update 1: For the Phobos-Grunt re-entry on 2012-01-15, there is a great archive of TLEs and predictions at Phobos Grunt Re Entry Information - SPACEFLIGHT101.

For UARS, the best option I ran across was to watch UARS Orbit Data at and copy/paste from there a few times. The first two lines of each section are the "Two-Line Element Sets" - see Orbital Elements at for an explanation of each number:

1 21701U 91063B   11267.10904230  .15227068  11945-4  11522-3 0  6420
2 21701 056.9313 262.1789 0003645 318.1436 041.9334 16.52554649109189

Epoch (UTC):    02:37:01, Saturday, September 24, 2011
Eccentricity:   0.0003645
Inclination:    56.9313°
Perigee height: 130 km
Apogee height:  135 km
Right Ascension of ascending node:  262.1789°
Argument of perigee:    318.1436°
Revolutions per day:    16.52554649
Mean anomaly at epoch:  41.9334°
Orbit number at epoch:  10918

1 21701U 91063B   11266.92730638  .09135854  11791-4  18500-3 0  6390
2 21701 056.9390 263.1012 0003809 338.0534 022.2824 16.46920535109153

Epoch (UTC):    22:15:19, Friday, September 23, 2011
Eccentricity:   0.0003809
Inclination:    56.939°
Perigee height: 145 km
Apogee height:  150 km
Right Ascension of ascending node:  263.1012°
Argument of perigee:    338.0534°
Revolutions per day:    16.46920535
Mean anomaly at epoch:  22.2824°
Orbit number at epoch:  10915
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