Nasa satellite the size of bus 'could land almost anywhere'
08:29AM Thu 22 Sep, 2011
A 20-year-old Nasa satellite the size of a bus is heading for Earth and expected to hit on Friday.
Nasa and the US Department of Defense are tracking the 35ft spacecraft, the Upper Atmosphere Research Satellite, or (UARS), as it heads towards the planet at five miles per second.
Experts say there is a one-in-3,200 risk of the space junk, which weighs six tons, hitting someone.
However, its speed means that there will only be a 20-minute warning before it strikes.
Debris is expected to scatter across a 500-mile area, with the biggest chunk weighing 300lb, the weight of a large refrigerator.
The anticipated landing area spans cities as far north as Edinburgh and as far south as Cape Horn, on the southern coast of South America.
NASA spokespeople have stressed that the risk to human life and property from UARS is small.
They cite the statistic that in 50 years of space exploration no one has ever been hurt by falling space junk, while they claimed that people were much more likely to be fatally struck by lightning.
Mark Matney, an orbital debris scientist at NASA, said: "We know it is going to hit somewhere between 57 north latitude and 57 south latitude, which covers most of the inhabited world unfortunately."
The biggest piece of space debris to fall from orbit was America's 75-ton Skylab which hit Earth in 1979.
UARS was launched in 1991 to measure the ozone layer, wind and temperature. It was officially decommissioned in 2005.
It is the biggest NASA spacecraft to "come back" in three decades, after Skylab fell in western Australia but Mr Matney said similar-sized pieces of spent rocket and satellite debris fall to Earth about once per year.
US Strategic Command's Joint Space Operations Center is "keeping everyone - not just NASA but all the federal agencies that deal with public safety issues - informed about where it is and predictions of where it's coming," a spokeswoman said.
NASA has warned people not to touch the debris if they come across it because it is likely to have sharp edges.
source: The Telegraph
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