[Omah]

By Paul Rincon

Science editor, BBC News website

http://www.bbc.co.uk/news/science-environment-15009337

An amateur astronomer has recorded images of the out-of-control US satellite as it tumbles back to Earth.

Theirry Legault, from Paris, captured the video as the satellite passed over northern France on 15 September.

The six-tonne, 20-year-old spacecraft has fallen out of orbit and is expected to crash somewhere on Earth on or around 24 September.

The US space agency says the risk to life from the Upper Atmosphere Research Satellite (UARS) is 1 in 3,200.

Mr Legault, an engineer, used a specially designed camera to record the tumbling satellite through his 14-inch telescope, posting the footage on his Astrophotography website.

UARS could land anywhere between 57 degrees north and 57 degrees south of the equator - most of the populated world.

Nasa says that most of the satellite will break or burn up before reaching Earth.

But scientists have identified 26 separate pieces that could survive the fall through the atmosphere. This debris could rain across an area 400-500km (250-310 miles) wide.

Robust, spherical satellite components such as fuel tanks are often most likely to survive the fiery plunge to Earth, say space experts.

The "productive scientific life" of UARS ended in 2005 when it ran out of fuel
Nasa said scientists would only be able to make more accurate predictions about where the satellite might land two hours before it enters the Earth's atmosphere.

Amazing footage .....

[GypsyGoth]

It's just a blurry light

[Omah]

Originally Posted by GypsyGoth

It's just a blurry light

That's because it's "far away", probably over 50 miles "high", and moving at several thousand miles per hour .....

[lostalex]

It's pretty.

[Omah]

http://www.bbc.co.uk/news/magazine-15023115

Fragments from a satellite falling to Earth are expected to land on Friday. So is it possible to take evasive action?

A six-tonne satellite is expected to crash land in the next 24 hours, scattering debris over an area of the planet's surface up to 500km (310 miles) wide.

Nasa, which owns the Upper Atmosphere Research Satellite (UARS), estimates it will break into about 26 parts, the heaviest weighing about 158kg, which is equivalent to a very large person.

The debris will include three batteries, four wheel rims and four fuel tanks, and their speed when they hit the ground or the ocean will vary.

The rims, for example, could reach speeds of 107 metres per second (240mph), which is faster than one of France's high-speed TGV trains and 10 times quicker than Usain Bolt.

So is it possible for humans to ensure they don't get hit?

"Potentially, you could get out of the way," says Richard Crowther of the UK Space Agency, which is a member of a global network of agencies that monitors space debris.

"But if you're going to spend all the time looking up then you're at greater risk of an accident bumping into something than something coming down on you."

Equally, if you want to avoid the risk of being hit completely, he says, then you need to go beyond 57 degrees latitude north (Scotland or Quebec) or south (further south than the southern tip of Argentina).

"But travelling there will involve a greater risk than the risk of being hit by this."

Do you feel lucky ?

[Benjamin]

I just saw a a couple of shooting stars about twenty minutes ago. Reckon it could be any pieces of this?

[Benjamin]

Originally Posted by Omah

http://www.bbc.co.uk/news/magazine-15023115



Do you feel lucky ?

Imagine if you were the unlucky one. Just happily going about your day, in the shop deciding what chocolate bar to buy and then BAM!... hit by a fuel tank from the satellite.


I shouldn't laugh, it'll be me now...


-looks up-

[Kerry]

Just seen a snippet on the news. Had no idea


*looks up too*

[Omah]

http://www.bbc.co.uk/news/science-environment-15034073

US officials now say the fall to Earth of Nasa's six-tonne UARS satellite could occur early on Saturday (GMT).

Estimates of where debris might fall will be narrowed hours before impact.

And a UK team studying the trajectory says the most likely time for re-entry could be after 23:00 GMT Friday, and as late as 03:00 GMT on Saturday.

Most of the decommissioned and now unpowered spacecraft should simply burn up, but modelling work suggests perhaps 500kg could survive to the surface.

UARS is the largest American space agency satellite to return uncontrolled into the atmosphere in about 30 years.

As of 15:30 GMT on Friday, the satellite was orbiting at an altitude between 160km and 170km (100 miles by 105 miles).

If the estimates for its re-entry are correct, it means the spacecraft will not come in over North America.

"The spacecraft orbits the Earth in 90 minutes, so even if we're off by a few minutes in the prediction - that's thousands of kilometres down range," said Mark Matney, an orbital debris scientist from Nasa's Johnson Space Center.

"We'll be able to know generally a few hours before, but we'll only get a final report after it re-enters. Even then, we won't know where the pieces fall because they'll be scattered over a 500-mile path," he told BBC News.

The Upper Atmosphere Research Satellite (UARS) will start to tumble rapidly when it engages the top of the atmosphere, about 80km up.

Mechanical forces will rip off less robust structures such as the solar array and antennas.

The heating that the satellite then experiences as it plunges deeper into the atmosphere will start to deform and melt low-temperature materials and then vaporise them.

Components expected to survive are made from high-temperature metals such as stainless steel, titanium and beryllium.

Some 26 items have been suggested as impactors. The largest is one of UARS' instrument tables and weighs over 150kg.

With more than 70% of the Earth's surface covered by water, the chances are that any debris will fall into the ocean.

But if the re-entry does occur over populated areas of land, it should make for a spectacular streak across the sky, even in daylight.

[Shardlake]

You would think that with all their supposed technology and 'experts' they could give us a better time frame than ' the most likely time for re-entry could be after 23:00 GMT Friday, and as late as 03:00 GMT on Saturday.'

[Omah]

Originally Posted by Shardlake

You would think that with all their supposed technology and 'experts' they could give us a better time frame than ' the most likely time for re-entry could be after 23:00 GMT Friday, and as late as 03:00 GMT on Saturday.'

http://www.bbc.co.uk/news/science-environment-15021323

Satellite and space expert Dr Stuart Eves stressed the large uncertainties involved in tracking the "decay" of satellite orbits (their slow fall back into the Earth's atmosphere).

Using the most recent determination of UARS' orbit - taken in the early hours of this morning - Dr Eves and a colleague have come up with their own projections of the satellite's final descent. But he explained that a spacecraft's orbit lifetime could only be estimated to about 10% accuracy.

This translates to a six-hour window either side of the expected decay which is based on a range of probabilities. Calculations using the data available on Thursday afternoon suggested a splash down in the Southern Ocean. But this is likely to change as tracking specialists get a better fix closer to Friday evening.

Given the 10% accuracy figure, and the fact that UARS takes about one-and-a-half hours to complete an orbit of Earth, the satellite could come down during one of four possible orbits of Earth on Friday evening/Saturday morning.

And a number of different estimates could be produced depending what software is used to model the satellite's decay, explained Dr Eves, who is lead mission concept engineer at Surrey Satellite Technology Limited (SSTL).

Satellite decays can be affected by a number of different factors, such as the shape of the spacecraft and its unpredictable tumbling, as well as heating of the Earth's atmosphere by ultraviolet radiation from the Sun.

This can make the atmosphere expand, causing UARS to fall to Earth faster than expected.

But other conditions could see the satellite stay in space for longer than anticipated.

[Omah]

http://www.nasa.gov/mission_pages/uars/index.html

Update #10
Fri, 23 Sep 2011 03:45:08 PM UTC+0100

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.

[Ramsay]

Im scared

[Omah]

Update #11
Sat, 24 Sep 2011 12:30:46 AM UTC+0100

As of 7 p.m. EDT on Sept. 23, 2011, the orbit of UARS was 90 miles by 95 miles (145 km by 150 km). Re-entry is expected between 11 p.m. Friday, Sept. 23, and 3 a.m., Sept. 24, Eastern Daylight Time (3 a.m. to 7 a.m. GMT). During that time period, the satellite will be passing over Canada, Africa and Australia, as well as vast areas of the Pacific, Atlantic and Indian oceans. The risk to public safety is very remote.

[Ninastar]

aww i want to see it

[Novo]

It's going to hit Locke square on the forehead and knock him into the middle of the next millenium

[Benjamin]

I wonder if anyone will get killed by it?

[Kerry]

Slightly amusing on the news right now they are announcing that NASA are asking people to report sightings

I say amusing........

[lostalex]

Originally Posted by ukturtle

I wonder if anyone will get killed by it?

They said on the news that the chances of it hitting a person are 1 in 22 TRILLION. lol

So if it does, he or she must be VERY unlucky.

[Omah]

Update #15
Sat, 24 Sep 2011 08:46:42 AM UTC+0100

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.

[Omah]

Update #16
Sat, 24 Sep 2011 04:37:25 PM UTC+0100

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.

[Beastie]

Phew. That's good. I thought I was going to get hit.

What if they hit a boat with a full of people on it in the Pacific Ocean?

[Omah]

Originally Posted by Beastie

Phew. That's good. I thought I was going to get hit.

What if they hit a boat with a full of people on it in the Pacific Ocean?

I would win £1,000,000,000,001.00 at the bookies .....

[Niall]

It was ridiculous the way they hyped it up omfg.

[Marc]

A massive shard of metal hit me yesterday.

That footage is pretty, I wouldn't know what to do if I saw it. I'd think the world was ending or something