A team of scientists are flying across the Australian Outback this afternoon to recover a Japanese space capsule they hope contains the first-ever asteroid samples that could provide clues into the creation of the solar system.
The Hayabusa explorer returned to Earth overnight after a seven-year, 4-billion mile journey, burning apart on re-entry in a spectacular fireball just after jettisoning the capsule. It was the first time a spacecraft successfully landed on an asteroid and returned to Earth.
Nasa scientist Scott Sandford said it was a relief to watch the re-entry and see the capsule had successfully detached and parachuted to Earth.
"During a mission critical event like a re-entry, there's a whole series of things you've got to get right to make it work, and they all seemed to have come off without a hitch," said Sandford, an astrophysicist and one of the team members who will research the samples. "It's a great testament to the design and operation of the spacecraft."
Two helicopters were taking scientists to the capsule's landing site in the Woomera Prohibited Area, a remote military zone in South Australia 500km northwest of Adelaide.
It could take many hours to retrieve the capsule and collect samples, which will then be taken to Japan for study, he said.
Considering the problems that have plagued the Japanese space probe Hayabusa during unmanned mission, it was remarkable that it returned home at all, never mind in quite so spectacular a fashion.
Launched by the Japan Aerospace Exploration Agency in 2003, the spacecraft had the mission of collecting samples from an ancient asteroid, Itokawa, about a billion miles away, beyond Mars. It landed there in 2005, but a litany of problems delayed its return by three years.
The probe's sampling collection device failed, but scientists believe it must have picked up microscopic grains of dust while landing on Itokawa. Even one grain can be "sliced into more than 100 pieces and farmed around the world for testing and research", according to Michael Zolensky, one of two Nasa scientists involved in the project.
Researchers hope to study how and when the asteroid was formed, its physical properties, and what other celestial bodies it may have been in contact with. The aim is to gain fresh insight into the origin and evolution of the solar system, and also to reduce the threat of an asteroid colliding with Earth.
During the US$200m mission, Hayabusa - which means "falcon" in Japanese - suffered fuel leaks, engine problems and malfunctioning of its stabilising wheels and electricity-storing batteries. The car-sized probe also lost communication for seven weeks. Some dubbed it the "robotic equivalent of Apollo 13", which was beset by technical problems but managed to limp home after aborting a lunar landing.
Stretches of South Australia's main north-south highway, as well its transcontinental train line, were closed in anticipation of the capsule's landing in the Woomera rocket test range, a military zone.
Aboriginal elders were planning to accompany scientists retrieving the capsule - before it is flown to Japan - to make sure it had not damaged any sacred sites.
The first spacecraft to complete a round-trip journey to an asteroid, Hayabusa is only the fourth to bring home space material. Samples were collected on the Moon; during Nasa's Genesis mission in 2004, which picked up particles of solar wind; and during the 2006 Stardust mission, which returned with samples of a comet.
Trevor Ireland, a geochemist at the Australian National University and a member of the team, said: "There's absolutely nothing like going to the source. Hayabusa has sampled an asteroid in situ and soon we will have in hand an actual asteroid. Any sample coming back from Itokawa will be a major scientific prize for us."
Dr Zolensky said even one grain could shed light on the asteroid's chemical and mineralogical characteristics. "You can do incredible things with a sample that small." On the question of an asteroid colliding with Earth, he said: "If you want to mitigate that hazard, you have to know about the physical properties of asteroids."
As well as bringing dust home from Itokawa, the probe left a souvenir of Earth on the asteroid: an aluminium plate bearing the names of 880,000 people from 149 countries, including the US film-maker Steven Spielberg and the British science fiction writer Arthur C Clarke.
- INDEPENDENT, AP