Space invader on target for Australia after 4 billion kilometre trip
Deborah Smith, Science Editor
ITS arrival will be a triumph of ingenuity and perseverance over adversity. Crippled, out of fuel, and three years late, the first spacecraft to land on an asteroid and return to Earth is about to touch down in the Australian outback.
The unmanned Japanese probe, Hayabusa, or Falcon, is set to release its cargo capsule over the Woomera Prohibited Area in South Australia on Sunday night, at the end of a 4billion-kilometre journey. Even if the capsule does not contain any soil from the asteroid as hoped, its landing about 11.30pm will be a great achievement and tribute to the tenaciousness of the Japanese space agency, said Glen Nagle, the spokesman for the Canberra Deep Space Communication Complex at Tidbinbilla.
The seven-year mission to Itokawa, a small asteroid just 540 metres long, has had to overcome fuel leakages, malfunctioning engines, and repeated loss of communication with Earth. ''What has been achieved in getting this spacecraft back is nothing short of remarkable,'' Mr Nagle said.
The CSIRO-managed NASA tracking station has been following Hayabusa since its launch in May 2003. When it gets close to Woomera the 500-kilogram spacecraft will be moving so fast it will have to be tracked from California. A Japanese and NASA team in a chase aeroplane with thermal imaging equipment will help pinpoint its landing position during its final descent, so the capsule can be recovered and returned to Japan, where its contents will be analysed by researchers including Professor Trevor Ireland of the Australian National University.
A year into its journey, Hayabusa swung by the Earth, using its gravity to accelerate towards the asteroid, a lump of debris left over from the birth of the planets 4.5 billion years ago. It arrived at the asteroid, about 300 million kilometres from Earth, in November 2005 and took photographs and remote sensing measurements which revealed it was a pile of loosely packed rubble. A small robot, named Minerva, was to have hopped across the surface of the asteroid, but its release was flawed and it drifted off into space. Although Hayabusa touched down on the asteroid twice, a system to fire a metal ball to kick up soil for collection did not operate properly and it is unclear whether any material was obtained. The spacecraft's chemical fuel leaked out, and three of its four electronic ion propulsion engines broke down. But the Japanese team was able to combine the parts on the crippled craft that still worked to bring it home.