Barometer | 24 September 2011
From our UK edition
Objects in space — The six tonne US Upper Atmosphere Research Satellite was due to fall to Earth, with Nasa calculating that it has a one in 3,200 risk of striking a human. It poses less of a risk, however, than the 75 tonne Skylab did when it re-entered the Earth’s atmosphere in 1979. In the event, it fell on an uninhabited region of Western Australia. — There is plenty more potential danger from space junk, with an estimated 19,000 pieces of man-made material greater than 100mm across orbiting the Earth, including a glove and a camera dropped by astronauts. Most will burn up in space when they re-enter, but one which could cause problems is Vanguard 1, a satellite launched in 1958 which is expected to fall to Earth in 240 years’ time.