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Rest In Peace Uars
BPCooper
post Dec 14 2005, 11:51 PM
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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.


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djellison
post Dec 14 2005, 11:58 PM
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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
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Guest_BruceMoomaw_*
post Dec 15 2005, 03:17 AM
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Guests






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.)
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djellison
post Dec 15 2005, 08:44 AM
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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
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Guest_BruceMoomaw_*
post Dec 15 2005, 11:13 AM
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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.
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RNeuhaus
post Dec 15 2005, 02:00 PM
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QUOTE (djellison @ Dec 14 2005, 06:58 PM)
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.

What a nice is that virtual UARS.

Rodolfo
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happypete
post Jan 27 2006, 09:10 PM
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QUOTE (BPCooper @ Dec 14 2005, 07:51 PM)
It's last good battery shorted out in August


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.
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Spin0
post Sep 12 2011, 06:43 PM
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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
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happypete
post Sep 14 2011, 01:41 PM
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QUOTE (Spin0 @ Sep 12 2011, 01:43 PM) *
UARS re-entry is expected during the last week of September 2011.


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.

smile.gif
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SolarSystemRubbl...
post Sep 19 2011, 11:25 AM
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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.
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Spin0
post Sep 20 2011, 09:47 PM
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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
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SolarSystemRubbl...
post Sep 21 2011, 02:10 PM
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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
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Holder of the Tw...
post Sep 22 2011, 06:19 PM
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North America has just been ruled out of the strike zone.

Dang, and I was planning a walk in O'Brien park.
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SolarSystemRubbl...
post Sep 22 2011, 06:44 PM
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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
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PDP8E
post Sep 22 2011, 08:18 PM
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...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!


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