Near-Earth orbit has become a more dangerous place, after the People's Republic of China became the third nation to test an anti-satellite weapon.

While Beijing has been silent on the matter, US intelligence sources say a medium-range ballistic missile was launched from China's Xichang space centre in Sichuan province on 11 January. The weapon is believed to have had a hardened warhead, which smashed into and ripped apart a defunct Chinese weather satellite flying at an altitude of 850 kilometres.

David Wright, a space weapons specialist at the Union of Concerned Scientists in Washington DC, says the 750-kilogram spacecraft would have fragmented into "millions of pieces" of fast-moving debris that could threaten both civil and military satellites.

China is not the first to destroy a satellite. In 1982, the Soviet Union was thought to have deployed a satellite that would rendezvous with a target spacecraft and then explode. And in 1985, the US destroyed a defunct science satellite with a ballistic missile.

Despite protests from the Bush administration over China's action, analysts point out that the US has consistently refused to discuss a new UN treaty on the peaceful uses of outer space. Instead, it will this year spend at least $1 billion on anti-satellite laser weapon research (New Scientist, 15 April 2006, p 30). "China and other countries have long called for discussions to develop a legal framework for space conduct, but the US has been unwilling to join them. As a result, China's anti-satellite test was legal," says Wright.

From issue 2588 of New Scientist magazine, 27 January 2007, page 23