Asteroid encounter postponed

Hayabusa is designed to gather space dust for return to Earth

The planned touchdown on an asteroid by a space probe has been postponed.

The Japanese Aerospace Exploration Agency said it had received an "anomalous signal" from the craft shortly before it was due to make its descent.

The Hayabusa spacecraft was launched in May 2003 on a mission to find out more about the raw materials that made up the early Solar System.

On Friday, it was due to land a robot on the surface of asteroid Itokawa.

Robot passenger

The 10cm-tall Minerva robot is designed to bounce across the surface of the asteroid, collecting temperature readings and images.

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

Friday's planned descent was designed to survey the landing site ahead of two attempts to gather samples of space dust for return to Earth.

The Hayabusa probe has been stationed over the giant space rock some 300 million km from Earth since September.

It 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.

Mission managers said that they had altered flight parameters so that the craft still had enough fuel onboard to make the landing attempts.

Hayabusa is due to begin its return voyage to Earth in December and is expected to arrive in June 2007. If successful, it will be the first spacecraft to return samples from an asteroid.