Japan's asteroid touchdown fails

The probe captured its shadow on the surface of the asteroid

An unmanned Japanese space probe sent to collect what would be the world's first samples from an asteroid has failed to touch down on its target.

The Japanese space agency said the Hayabusa probe had got to within 17m (56ft) of the asteroid before contact was temporarily lost.

The agency said it hoped to make a second attempt to land the craft.

The mission has had several setbacks. Last week a mini-robot due to collect data from the asteroid disappeared.

Early on Sunday, the probe descended towards the Itokawa asteroid and hovered about 17m from the surface without completing a touchdown. Contact was then lost with the probe for about three hours.

Stephen Lowry of Queen's University, Belfast, told the BBC News website: "After they regained contact with the probe, there was a lot of data sent back. They are now in the process of analysing that data."

Scientists were unclear as to whether the probe had developed a technical problem or an automatic failsafe device had prevented the landing.

"From an engineering point of view, we see this as a success. We definitely want to try again," project leader Junichiro Kawaguchi said.

No easy job

Hayabusa (Japanese for "falcon") had been scheduled to touch down on the asteroid's surface for just one second - long enough for the probe to fire a metal pellet into the asteroid and collect a sample of the material stirred up by the impact.

The craft successfully released a 10cm-wide metal ball to serve as a landing marker.

This target marker contains on two aluminum sheets the names of 880,000 people from 149 countries, including those of science fiction writer Arthur C Clarke, film director Steven Spielberg and manga artist Reiji Matsumoto.

The asteroid is named after Hideo Itokawa, a father of Japan's space programme Enlarge Image

Hayabusa was launched in May 2003 and has until early December before it must leave the asteroid's orbit and begin the 290-million-km (180 million mile) journey back to Earth.

It is expected to arrive in 2007.

The mission has encountered a number of difficulties.

The Minerva miniature robot disappeared while attempting to land on the asteroid's surface last week.

The 600g (1.3lbs) cylindrical probe was to have photographed the asteroid's surface and recorded temperatures there.

A previous "dress rehearsal" had to be aborted on 4 November. The spacecraft was within a few hundred metres of the asteroid when the operation was called off.

The spacecraft lost one of its three stabilising reaction wheels on 31 July, forcing it into an alternative flight mode. The second wheel failed on 3 October although these problems have now been rectified.