投稿者 gaattc 日時 2000 年 8 月 18 日 02:03:00:
Thursday, 17 August, 2000, 11:55 GMT 12:55 UK
Laser guard for space station
By Toby Murcott of BBC Science
The US space agency Nasa is to test a laser "broom" that is designed to sweep debris in space away from the path of the International Space Station.
The laser will target space junk between one and 10 centimetres in diameter. Nasa says that unless this debris is removed, there is the chance a stray piece of it might punch a hole in the station within a few years.
There are millions of bits of space junk circling our planet - the result of decades of blasting satellites into orbit.
Most are relatively harmless specks of dust, and a few are large chunks which, although potentially lethal were they to collide with the International Space Station, are easy to track and avoid.
But there are some fragments about the size of a tennis ball which are big enough to pierce a spacecraft but too small to monitor easily.
These intermediate bits of space junk are the target of Nasa's new laser space broom. This is a ground-based system that can locate and destroy or divert these fragments.
Trials of the system are due to start in 2003. The US space shuttle will launch dummy targets of a similar size, and a laser back on Earth will attempt to lock on to them.
These trials will not involve lasers with sufficient power to affect the debris, as there are concerns that such high power devices might contravene the international weapons treaty banning laser weapons in space.