Can You Dodge a Falling Satellite?

The UARS was launched in 1991 by the Space Shuttle Discovery.

 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).

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.  You could dodge a fragment if it's daytime, you get a clear view and you see it in time.But some pieces will travel at high speeds. And experts will only know where the debris will land minutes beforehand.
Some pieces could injure a person or damage property,but the chance of it hitting a person is put at one in 3,200. "But if you're going to spend all the time looking up then you're at greater risk of 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."

Even if it is coming to your neighbourhood, you won't get much notice. Nasa is tracking the object in orbit and said on Thursday that it was expected to re-enter the atmosphere on Friday afternoon on the US east coast.  But Nasa doesn't know exactly where it will land, partly due to continuous changes in the atmosphere caused by the Sun. And the uncertainty surrounding the satellite's final destination will continue until its final minutes.


In 1979, when the Skylab space station fell to Earth, it missed the expected landing in South Africa and crashed in Western Australia. So good luck and duck.