Warning system will be out of this world
- Earth should welcome China’s proposal to build largest system of radars to identify threats from space, such as asteroids, as well as monitor satellites
It’s the kind of prestige project that China has always found hard to resist. It boosts international credibility, offers a genuine service to humanity and provides another opportunity to get the better of the United States.
The world has so far relied on the US for such monitoring. But the American efforts are falling behind. One key radar, at the Arecibo Observatory in Puerto Rico, collapsed in December because of hurricane damage, ageing, and lack of repair and maintenance from insufficient funding. This leaves only the Goldstone Solar System Radar in a Californian desert.
More than 400,000 asteroids have so far been identified in the solar system. One of them, an 18-metre wide asteroid, exploded 30km above Chelyabinsk, in the Russian Urals, in February 2013, injuring more than 1,000 people. The energy released by the explosion was estimated to be up to 30 times that of the Hiroshima atomic bomb. Clearly, the celestial threat, while small, is not negligible. And if it does happen, it could end in catastrophe.
The proposed system may involve up to five 35-metre diameter radars in Kashgar, Xinjiang, to send powerful beams into space. The returned signals would be picked up by large antennas across China. The detection range of the system is expected to exceed 0.1 astronomical unit, equivalent to a tenth of the mean distance between Earth and the sun.
The Chinese plan will fit nicely in an existing global advance warning system. The United Nations operates an international asteroid detection network that issues global warnings if one such body greater than 50 metres in diameter may hit Earth with a likelihood greater than 1 per cent in 50 years. However, it relies on the system maintained by the Americans, whose commitment is unclear. Undoubtedly, a second and more advanced warning system is warranted; all the better that China is willing to pick up the bill.
