http://news.uk.msn.com/Article.aspx?...mentid=7482800
If half of it does survive re-entry, 2500lbs on your head is bound to hurt.
Dead spy satellite set to hit Earth
A dead US spy satellite in a deteriorating orbit is expected to hit the Earth during the first week of March.
Where the satellite will hit is not known. Officials familiar with the situation say about half of the 5,000lb spacecraft is expected to survive its blazing descent through the atmosphere and will scatter debris, some potentially hazardous, over several hundred miles.
The satellite has thrusters, small engines used to position it in space, that contain the toxic rocket fuel hydrazine. Hydrazine can cause harm to anyone who comes into contact.
The satellite, known by its military designation US193, was launched in December 2006. It lost power and its central computer failed almost immediately afterwards, leaving it uncontrollable. It carried a complex and secret imaging sensor.
US officials do not want the equipment to be recovered by people who should not have control of it.
"The Chinese and the Russians spend an enormous amount of time trying to steal American technology," said John Pike, a defence and intelligence expert.
"To have our most sophisticated radar intelligence satellite - have big pieces of it fall into their hands - would not be our preferred outcome."
Where it lands will be difficult to predict until the satellite descends to about 59 miles above Earth and enters the atmosphere. It will then begin to burn up, with flares visible from the ground, says Ted Molczan, a Canadian satellite tracker. From that point on, he said, it will take about 30 minutes to fall.
In the past 50 years about 17,000 man-made objects have re-entered the Earth's atmosphere. The largest uncontrolled re-entry by a Nasa spacecraft was Skylab, a 78-ton abandoned space station that fell from orbit in 1979. Its debris dropped harmlessly into the Indian Ocean and across a remote section of western Australia.
In 2000, Nasa engineers directed a safe de-orbit of the 17-ton Compton Gamma Ray Observatory, using rockets aboard the satellite to bring it down in a remote part of the Pacific Ocean.
A dead US spy satellite in a deteriorating orbit is expected to hit the Earth during the first week of March.
Where the satellite will hit is not known. Officials familiar with the situation say about half of the 5,000lb spacecraft is expected to survive its blazing descent through the atmosphere and will scatter debris, some potentially hazardous, over several hundred miles.
The satellite has thrusters, small engines used to position it in space, that contain the toxic rocket fuel hydrazine. Hydrazine can cause harm to anyone who comes into contact.
The satellite, known by its military designation US193, was launched in December 2006. It lost power and its central computer failed almost immediately afterwards, leaving it uncontrollable. It carried a complex and secret imaging sensor.
US officials do not want the equipment to be recovered by people who should not have control of it.
"The Chinese and the Russians spend an enormous amount of time trying to steal American technology," said John Pike, a defence and intelligence expert.
"To have our most sophisticated radar intelligence satellite - have big pieces of it fall into their hands - would not be our preferred outcome."
Where it lands will be difficult to predict until the satellite descends to about 59 miles above Earth and enters the atmosphere. It will then begin to burn up, with flares visible from the ground, says Ted Molczan, a Canadian satellite tracker. From that point on, he said, it will take about 30 minutes to fall.
In the past 50 years about 17,000 man-made objects have re-entered the Earth's atmosphere. The largest uncontrolled re-entry by a Nasa spacecraft was Skylab, a 78-ton abandoned space station that fell from orbit in 1979. Its debris dropped harmlessly into the Indian Ocean and across a remote section of western Australia.
In 2000, Nasa engineers directed a safe de-orbit of the 17-ton Compton Gamma Ray Observatory, using rockets aboard the satellite to bring it down in a remote part of the Pacific Ocean.
If half of it does survive re-entry, 2500lbs on your head is bound to hurt.
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