The Upper Atmospheric Research Satellite, deployed Sept. 12 1991 from the Space Shuttle Discovery, was decomissioned today. It's last good battery shorted out in August and planning to end the mission went as planned and concluded today with the shutting down of the satellite. Last week, a several-minute burn lowered the orbit of the satellite.

It is expected to make an uncontrolled reentry in 2008 or 2009. UARS opened a wealth of understanding on the upper and lower atmospheric layers including monitoring the ozone layer.

Always sad to see a great spacecraft come to the end of it's life, but it's an opportunity to reflect on all that it has taught us.

Doug

The Earth Radiation Budget Satellite -- launched by Shuttle in 1984 -- is also finally about to be turned off. It's a measure of how difficult it is to study global warming without satellites that, until ERBS, we were in the dark about even such a fundamental question as whether Earth's current cloud cover is warming or cooling the planet! (The answer, provided by a few years of ERBS observations, is that it is significantly cooling us.)

At least the GERB instrument on the first MSG ( made right here in Leicester ) can take up from ERB.

Is the sort of data that UARS was taking being filled in for by the A-Train?

Doug

I believe so (although I'd have to review my documents on the A-Train). Certainly the "Aura" satellite is supposed to make improved versions of most of UARS' observations, and I believe all of them.

What a nice is that virtual UARS.

Rodolfo

Actually, according to the final weekly report, both remaining "good" batteries were performing acceptably up to the end. One must presume that the passivation of the system was driven by the gradual decline in available power and other failures, and the availability of science data from instruments on other birds.

UARS re-entry is expected during the last week of September 2011.

NASA and U.S. Strategic Command will give updates here: http://www.nasa.gov/mission_pages/uars/index.html

Thanks for the update. It looks like UARS stayed aloft a lot longer than originally predicted after they passivated it in 2005. Typical behavior, though, for a satellite that stretched its "eighteen month" minimum design life into 14 years of valuable reporting on our planet's upper atmosphere.

Prepare for UFO and fireball reports!

This will be an uncontrolled reentry, so could occur anywhere from 57 degrees N to 57 degrees South latitude.

Latest estimate is Sept 23 +/- 1 day

The risk assessment is interesting reading:

http://www.nasa.gov/pdf/585584main_UARS_Status.pdf

Total dry mass at start 5668 kg

– Number of potentially hazardous objects expected to survive: 26
– Total mass of objects expected to survive: 532 kg
– Estimated human casualty risk (updated to 2011): ~ 1 in 3200

• No NASA or USG human casualty reentry risk limits existed when UARS
was designed, built, and launched.

• NASA, the USG, and some foreign space agencies now seek to limit human
casualty risks from reentering space objects to less than 1 in 10,000.

• UARS is a moderate-sized space object. Uncontrolled reentries of objects
more massive than UARS are not frequent, but neither are they unusual.
– Combined Dragon mockup and Falcon 9 second stage reentry in June 2010 was more
massive.

• Since the beginning of the space age, there has been no confirmed report
of an injury resulting from reentering space objects.

• NASA, DoD, and the IADC will be monitoring the decay and reentry of UARS
carefully.

Thierry Legault shot a video of the tumbling UARS: http://legault.perso.sfr.fr/uars_110915.html

Re-entry still expected by Sept. 23 +- a day.

As of Sept. 20, 2011, the orbit of UARS was 127 mi by 140 mi (205 km by 225 km). Re-entry is expected Sept. 23, plus or minus a day. It is still too early to predict the time and location of re-entry. Predictions will become more refined over the next two days.
http://www.nasa.gov/mission_pages/uars/index.html

As of 1000 UTC today, the orbit is down to 195 x 209 km (121 x 130 mi) falling at a rate of 8 (perigee) and 11 (apogee) nper day.

This has not yet been incorporated into the reentry time forecast, that's still based on yesterday's orbit update, which predicted Sept 23 20:36 UTC +/- 20 hours:

http://reentrynews.aero.org/1991063b.html

When it get down to about 120 km, the atmosphere grabs it, and it falls during that orbit.

MW/SSR

North America has just been ruled out of the strike zone.

Dang, and I was planning a walk in O'Brien park.

By who? The latest map has a stripe across north americas two orbits after the center time of the reentry window, as well as the following 2.

Orbit is now 184 x 195 km, deccreasing at 9 and 13 km per day. The end is near

Map:

http://reentrynews.aero.org/1991063b.html

...from the site cited in the last post:

Reentry Prediction:
Predicted Reentry Time: 23 SEP 2011 @ 22:07 UTC ± 9 hours

± 9 hours means 6 orbits
where are the perigee points? They are the most likely places where UARS starts to sink into the atmosphere

( that may be why (maybe) North America has been ruled out? (by whom?) )

Personal Plea: Please make these interminable clouds go away!

I would assume (and it's just an assumption) that it's at the the point of most likely reentry as shown on the map.

Here is one source ...

Space.com

Best to only read the story and ignore the comments.

Well that's certainly far different than the map that I posted... We shall see.

BTW, the map has been updated with the latest orbital elements. It is now sept 24, on an orbit that crosses the US 20 minutes later.

Sept 24 0058 UTC +/- 7 hours (5 orbits). That's about 9PM EDT

http://reentrynews.aero.org/1991063b.html

That is 9pm EDT on the 23rd (in US and Pacific target) 1 am 24th in UK. Time zones

Yeah thanx, I should have mentioned it's the 23rd evening in the US.

Last info I read said it would NOT be over the USA......

South Pacific now:
http://reentrynews.aero.org/1991063b.html

(not too far from Mir back in 2001)

That's the same map I posted 6 hours earlier, it hasn't ben updated since. Besides the time is +/- 7 hours, so I wouldn't focus of any particular orbit yet.

BTW, I see a NOTAM has been issued...

Over the Sahara now. Still mostly empty areas.

http://reentrynews.aero.org/1991063b.html

the reentry point is now in Africa

it like 3 Card Monty !

I don't know if aero.org does any independent analysis or just works off of http://www.nasa.gov/mission_pages/uars/index.html. Unfortunately they have not updated from report #10 at 10:45 am EDT this morning. Maybe they are waiting until one orbit left to post...

First post !

The latest info -
145 x 150 km, 56.9° (Epoch Sep 23)
Reentry expected in the next 2-4 hours!

Just some more details...

Latest update as of 2215 UTC, demise is ~ 7 hours away (3 hours now), and the US is finally off the table.

Orbit at that time (about 4 hours ago) was 145 x 150 km (90 x 93 mi). Down 17 and 20 km in the preceeding 12 hours.

Estimated crash time is 0510 UTC Sept 24 +/- 2 hours, over the very south Pacific west of Australia, although the earlier and later orbits include Canada, Africa and Australia of the landmasses.

MW

It should be down by now, or very soon.

UNCONFIRMED reports (from twitter) that it may have come down over Quebec 40 minutes ago.

Also, earlier lights reported over Edmonton would make sense as the first pieces started to come off. Pretty certain this is accurate.

Northern Quebec's pretty empty (but not so empty that pieces can't be recovered). Can't wait till morning!

Hope no one wakes up with a headache or a new skylight!

Several independent reports coming in from southern Alberta about a debris trail in the sky moving rapidly.

now saying the pacific

NASA Statement:

Update #15
‎Today, ‎September ‎24, ‎2011, ‏‎3 hours ago
NASA’s decommissioned Upper Atmosphere Research Satellite fell back to Earth between 11:23 p.m. EDT Friday, Sept. 23 and 1:09 a.m. EDT Sept. 24. The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite penetrated the atmosphere over the Pacific Ocean. The precise re-entry time and location are not yet known with certainty

That is a rather long window for splashing in the Pacific. I was up in the night so followed the activities on Twitter. IamUARS was great fun. Really expected more from NASA; NASA_Watch; and other sites, but alas little real information has yet been released.

If it did indeed come down over the Pacific, there aren't a lot of eyes out there...of any kind.

Of course the breathless reports are coming in all over from what were probably common meteors. Due to the media storm, people who have never looked at the sky before were peering upward, and for last night, everything wasn't a UFO, it was a UARS

That's because little information exists. What do you want NASA to do - make stuff up?

They reported all the info they had as quickly as can be expected.

millions of fishes and other creatures disagree...

True, but most don't communicate with Space Command or NASA

I wasn't trying to give NASA a hard time, just thought other US agencies who track space objects and threats would have passed NASA some information. We have spy satellites that would have picke up the IR signal of reentry etc. It will probably just take a while for this information to get declassified and released.

Update #16
‎Today, ‎September ‎24, ‎2011, ‏‎37 minutes ago
NASA’s decommissioned Upper Atmosphere Research Satellite fell back to Earth between 11:23 p.m. EDT Friday, Sept. 23 and 1:09 a.m. EDT Sept. 24. The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite entered the atmosphere over the North Pacific Ocean, off the west coast of the United States. The precise re-entry time and location of any debris impacts are still being determined. NASA is not aware of any reports of injury or property damage.

This is your source for official information on the re-entry of UARS. All information posted here has been verified with a government agency or law enforcement.

NASA will conduct a media telecon at 2 p.m. ET to discuss the re-entry. The telecon will be streamed live at www.nasa.gov/newsaudio.

Map of Final orbit with most likely point where center of debris track would be at 10 km height.

http://www.nasa.gov/pdf/591662main_UARS%20Map.pdf

Also at the peak of the re-entry time, the tracking website was overloaded...as always happens during "events".
Also I cannot believe the US DOD don't know EXACTLY where the debris splashed/impacted.....

It's conceivable. You'd have to conclude they know where Mars 96 is, too. That's tinfoil hat territory.

USSTRATCOM is now quoting decay time as 0400 GMT plus or minus one minute.

That's even further out in the Pacific then...

Apparently a very good outcome: remote area of S. Pacific:

http://news.yahoo.com/nasa-satellite-fell-...-201709293.html