November 29, 2005

Asteroid Probe’s Return Journey in Doubt

TOKYO -- The future of a Japanese space probe carrying the world's first samples from an asteroid was in doubt on Tuesday, after it suffered problems with its chemical thrusters and temporarily lost contact with ground control.

Scientists at the Japan Aerospace Exploration Agency (JAXA) were triumphant at the weekend when Hayabusa, whose name means "falcon" in Japanese, appeared to succeed in landing on Itokawa and scooping up a rock sample after an epic two and a half year voyage.

But the unmanned probe was later found to be suffering a fuel leak from one of its two sets of chemical thrusters and a problem with the other set, which was possibly frozen, JAXA said.

"If we cannot revive the thrusters, of course a return journey is impossible," project leader Junichiro Kawaguchi told a news conference in Tokyo.

JAXA was picking up a beacon signal from Hayabusa on Tuesday, after having lost touch with the craft completely the previous day.

But the orientation of the probe was such that scientists were having difficulty sending commands and collecting data.

Kawaguchi said he did not have enough data to say whether the probe could be spun around to the desired orientation, or if it retained enough fuel after the leak to complete the return journey.

He said Hayabusa likely remained within several tens of kilometers of the asteroid, but was unable to pinpoint its exact location.

Asteroids, unlike larger space bodies, are believed to contain rocks that have remained largely unchanged since the early days of the solar system and can thus offer valuable information about its origins.

Information about their structure could also be vital if an asteroid were found to be on a collision course with the earth.

The probe had taken two and a half years to travel to Itokawa, about 300 million km (186.4 million miles) from earth, where it eventually landed twice. The asteroid is named after pioneering Japanese rocket scientist Hideo Itokawa.

Scientists cannot be absolutely sure the probe picked up a rock sample from the asteroid until the capsule containing the sample is dropped into the Australian outback - a procedure at present planned for June 2007.