Rocket to map `space junk'

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The Independent Online
FEARS THAT "space junk" orbiting Earth could damage satellites and injure astronauts on the space station have become so intense that the US Air Force has launched a rocket to study the problem.

The rapid growth of drifting debris, left as old satellites break up or collide, is contributing to a problem that has planners at the US space agency, Nasa, worried for future safety. Now a satellite, launched yesterday from Vandenburg Air Force base, California, will map the proliferation and density of the pieces of debris, travelling around the Earth at 17,000mph.

The particles range in size from pebbles to sand grains to microscopic motes. Yet their speed, relative to objects rising from Earth, means they can pack a terrible punch - enough to puncture or disrupt sensitive equipment. The Hubble space telescope and the space shuttle have been hit, though not seriously, by space junk. In the shuttle's case, an orbiting fleck of paint left a pit in one of its windows.

The problem is worsening too because collisions between pieces of junk produce more potentially lethal missiles.

"Many of these particles are produced by collisions between larger debris objects, and so information about these particles is important for understanding the whole debris population in Earth orbit," said Bruce McKibben, senior scientist at the University of Chicago's laboratory for astrophysics and space research. His team designed the instrument that will search for the debris.

The satellite will also try to distinguish between the amount of space junk left behind since Russia put Sputnik into space in 1956 and cometary dust and rocks left by celestial objects.