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Old 09-23-2011, 01:20 PM   #106
agentgonzo
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Predicted Decay Time: 2011-09-24 00:42:00 GMT +/- 15 Hours
Predicted Decay Location (altitude 10 km) : 46.1 S, 112.7 E
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Originally Posted by orb View Post
 It's in ocean.
Interesting that they give the decay time +/- 15 hours, but give the location as if it were exact, when a decay time of +10 minutes can equal thousands of miles... I say it could still land anywhere between 57N and 57S
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Old 09-23-2011, 02:58 PM   #107
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Originally Posted by agentgonzo View Post
 Interesting that they give the decay time +/- 15 hours, but give the location as if it were exact, when a decay time of +10 minutes can equal thousands of miles... I say it could still land anywhere between 57N and 57S
It's called periapsis. Or perigee, if you like.
And uncertainty is in the number of orbits.
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Old 09-23-2011, 03:52 PM   #108
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It isn't periapsis actually. It is the calculated point with simplified atmospheric model, in which the spacecraft would cross the 10 km altitude mark. It is almost falling straight down at that point.

Still, 15 hours are about 10 orbits and the ground track covers about 150 longitude of Earth in that time. +/- 15 hours means it can impact literally everywhere except in a small part of Earth that is 60 wide. You can exclude it reentering on its apoapsis passage, so luckily the zone is only half as big as it could be.
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Old 09-23-2011, 04:19 PM   #109
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Originally Posted by N_Molson View Post
 Please de-orbit your debris !! (in a controlled fashion)


I'm sorry, I just had to.
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Old 09-23-2011, 04:21 PM   #110
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Originally Posted by Urwumpe View Post
 You can exclude it reentering on its apoapsis passage, so luckily the zone is only half as big as it could be.
Not really, as the orbit will change so drastically during the last two-or-so orbits that what is currently its apogee is largely irrelevant to its trajectory in its final orbit. It could reenter anywhere on its current ground track.
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Old 09-23-2011, 04:31 PM   #111
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Originally Posted by agentgonzo View Post
 Not really, as the orbit will change so drastically during the last two-or-so orbits that what is currently its apogee is largely irrelevant to its trajectory in its final orbit. It could reenter anywhere on its current ground track.
Not really, the argument of periapsis simply changes strongly in that phase, but the periapsis passage remains the only candidate there.
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Old 09-23-2011, 04:39 PM   #112
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Originally Posted by N_Molson View Post
 Please de-orbit your debris !! (in a controlled fashion)
LOL

It was actually planned to be retrieved during a shuttle mission, until the Columbia disaster.

Can't remember if anyone posted this yet in the thread...
http://www.usatoday.com/tech/science...val/50529710/1
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Old 09-23-2011, 04:52 PM   #114
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As of 10:30 a.m. EDT on Sept. 23, 2011, the orbit of UARS was 100 miles by 105 miles (160 km by 170 km). Re-entry is expected late Friday, Sept. 23, or early Saturday, Sept. 24, Eastern Daylight Time. Solar activity is no longer the major factor in the satellite’s rate of descent. The satellite’s orientation or configuration apparently has changed, and that is now slowing its descent. There is a low probability any debris that survives re-entry will land in the United States, but the possibility cannot be discounted because of this changing rate of descent. It is still too early to predict the time and location of re-entry with any certainty, but predictions will become more refined in the next 12 to 18 hours.
From NASA's UARS section.
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Old 09-23-2011, 04:57 PM   #115
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Originally Posted by agentgonzo View Post
 Get inside a telephone box. Those things can stop a russian tank!
And they're bigger inside.
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Old 09-23-2011, 05:03 PM   #116
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Spaceflight Now: UARS Re-entry Updates

NASA: Solar Activity Can Affect Re-Entry of UARS Satellite
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Old 09-23-2011, 05:18 PM   #117
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Originally Posted by Ghostrider View Post
 And they're bigger inside.
No! Those aren't your usual telephone boxes, those are the police boxes.

Which are now apparently an anachronism.
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Old 09-23-2011, 07:19 PM   #118
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http://www.bbc.co.uk/news/science-environment-15034073

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UARS satellite return expected later
You wait all day for a falling satellite, and it turns up late!

N.
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Old 09-23-2011, 07:27 PM   #119
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It's coming Tuesday.
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Old 09-23-2011, 07:59 PM   #120
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No touchy, it's got sharp edges
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