Orbital Clash With Trash

Scripps Howard News Service:

The aerospace community knew a collision was inevitable and that, in turn, signaled a potentially worsening hazard for the space station, shuttle, orbiting telescopes and other satellites.

For the first time since man began the space age, with Sputnik in 1957, two fully intact satellites have collided, creating two large fields of orbiting debris. The statistical likelihood of this stuff colliding with something is small, but at orbital speeds of around 17,500 miles per hour it doesn't take much.

One satellite, belonging to the U.S. company Irridium, relayed phone calls; the other was a defunct Russian military Cosmos satellite. The American-owned satellite was launched in 1997, the Cosmos in 1993, and is believed to have been out of service for a decade. Occurring almost 500 miles over Siberia, it must have been quite a collision: The Cosmos weighed over a ton, the relay satellite 1,235 pounds.

An estimated 6,600 satellites have been launched in the last 51 years, and about 1,000 of those are operational. With China and now Iran launching satellites, there is going to be a lot of metal whizzing around Earth. The U.S. military and NASA now monitor something like 18,000 separate pieces of space debris, some of them quite small.

The space station and the shuttles can be moved if a threat is detected, and most commercial satellites can be repositioned. For whatever reason, the system failed with the defunct Cosmos, and scientists are now trying to find out why.

There have been space collisions before, but it has generally been debris that strikes other debris. This is the first time a fully functioning satellite has been taken out in a collision.

There does seem to be a need for stepped-up monitoring of space debris and perhaps an international convention on disposing of old satellites or parking them in orbits where they're not a threat. It says something that the most enduring aspect of humanity's reach for the stars is litter.

[출처 : 코리아타임스]