London, Feb 27 : Scientists have unveiled the design of a spacecraft that would assess the trajectory of a 300-metre wide asteroid, which has a tiny chance of striking Earth in 2036.
According to a report in Nature News, the mission would orbit an Earth-threatening asteroid known as Apophis.
Planetary Society advocates have said that the mission to the asteroid would not only assess its trajectory better than ground-based telescopes, it would also gather information about the asteroid's composition, shape and spin - crucial if engineers wanted to knock it off a path bound for Earth.
"We wanted to raise awareness of the near-Earth object threat and encourage deep thinking about a not-well-studied niche," said Bruce Betts, director of projects for the Planetary Society in Pasadena, California, which sponsored the competition for the perfect design of the spacecraft.
The winner of the 25,000 dollars first prize was SpaceWorks Engineering of Atlanta, Georgia, which proposed a simple spacecraft built largely from off-the-shelf components. ubbed "Foresight", it would orbit Apophis and send back radio signals to Earth even as it mapped the asteroid with a camera and laser rangefinder.
Ground-based telescopes - particularly those equipped with radar - are very good at tracking threatening asteroids, but only when they're close enough to spot, usually within about 15 million kilometres of Earth.
In 2013, Apophis will swing that close, and astronomers will have a better idea of the probability of a 2036 impact.
That would be confirmed in 2029, during another near-Earth pass that brings the asteroid closer than some satellites. But by then it could be too late to mount a serious Earth defence.
"If the object is on a collision course, we need a lot more lead time," said Steve Ostro, a radar astronomer at NASA's Jet Propulsion Laboratory in Pasadena. "A 2029 knowledge of a hit is way too late," he added.
Thus, a tracking mission would allow scientists to confirm an Earth-bound trajectory early on, and give aerospace engineers more time to plan to divert it.