This article was taken from the January issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online
Astronomers are on tenterhooks over the prospect of an asteroid colliding with Earth. Nasa has recently spotted two space rocks passing within 80,000km of the planet, as well as a 549m-wide asteroid that could hit us in 2182. Massimiliano Vasile, a lecturer in space research at the University of Glasgow, explains our options for saving the world.
Go nuclear "Unless you have [several years], the most effective way of dealing with an asteroid is a nuclear explosion," Vasile advises. "But there are issues." The first is getting to the asteroid, which could be hundreds of thousands of kilometres away. Controlling the explosion is the other problem. "If it doesn't go as planned, you may end up with several asteroids instead of one."
Gravity tractor This involves flying very close to an asteroid and using the gravity traction between the spaceship and the space rock as a kind of "rope" to pull it along. Then, a low-thrust engine moves the spacecraft away, pulling the asteroid and drawing it off course. "A relatively small spacecraft can [effect] a few hundred kilometres of deflection over seven years or more."
Lasers Or you can mount solar-powered lasers to a fleet of spaceships and direct the beams at the asteroid's surface until it vaporises, creating a plume of gas to drive it off course. "It would take three or four years to divert an asteroid one kilometre in diameter. Add training, building the spacecraft and deployment, and [the process] would take six to ten years."
This article was originally published by WIRED UK
