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| 6/21/2003 |
Space junk endangers our planet
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10:04:07 AM
Moscow, June 21 - The first collisions and explosions have already happened and the alarm bells are ringing: Our planet is slowly walling itself in with a dangerous mass of speeding space junk.
Russian space debris experts and their US colleagues at Nasa count up to 10,000 objects over 10 centimetres in diameter that circle the earth, a silent armada of mankind's mess - spent rocket stages and satellites, pieces of exploded and lost space equipment.
Then there are more than 100,000 objects between 1 to 10 cm, too small to be tracked by radar like the first category but potentially just as dangerous. These include nuts, bolts and other remnants.
Moving with an average relative velocity of about 10 kilometres a second they can wreck a satellite or, in the worst case scenario, rip into a manned spacecraft or even the International Space Station (ISS).
Even a tiny particle of a few millimetres will pierce an astronaut's space suit like a sniper's bullet if he is working outside.
"You essentially play the odds in this question of space debris -it's part of the mission you have no control over," said William Johnson, an American radar designer and participant in NASA missions.
"Debris isn't an issue in interplanetary missions but in earth missions it is, especially on manned ones. What you worry about is paint flakes - if one of those hits you, it'll make your day!"
Russian experts point out that for the time being, the odds are on our side, although freak incidents are occurring more often.
"For the most populated orbits the average probability is that a serious incident may happen once in 15 to 20 years, so the risk can still be considered acceptable," said Sergey Kulik, debris specialist at the Rosaviakosmos Aerospace Agency in Moscow.
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