Scientists hope Japan probe will return space dust

Scientists hope that a battered Japanese probe which touched down on an asteroid will bring back a big enough sample to provide valuable insights into outer space, Nasa said yesterday.

A canister containing asteroid dust ejected from the Hayabusa, or Falcon, is due to land in Australia's remote desert outback just before midnight on Sunday, ending a seven-year, five-billion-kilometre odyssey to a distant space rock.

Australian authorities have been tracking the Hayabusa since its launch in May 2003 and will help Japan's space agency, JAXA, recover the canister from its touchdown site in an off-limits military rocket-testing range.

Hayabusa's mission was beset with technical troubles. It lost communication with Earth for seven weeks, delaying its return for three years until the asteroid, Itokawa, and Earth again aligned.

But Nasa scientist Michael Zolensky said he was confident that the car-sized probe would send back enough of a sample to provide researchers with valuable clues on how the solar system has developed.

"It probably is going to return less than a gram of sample, at the most a couple of grams, possibly much less than that," Mr Zolensky told reporters in Australia.

"Even if the sampler did not work... as it was planned to do, there is good reason to expect that just the process of landing on the asteroid would have coated the inside of the spacecraft with dust," he added.

"When we open it up, I think it is not going to be empty."

Even a "microscopic grain" of an asteroid could be divided with a diamond knife into 100 samples or more, Mr Zolenky said.

Though Japan would have exclusive rights to it for the first year, he said anyone the world over would be entitled to study it after that.