The space agency said it could not confirm that its Hayabusa spacecraft dropped a small metal ball onto the surface, part of the project to collect material from an asteroid for the first time.

The ball was to mark the point where the spacecraft would gather rock and sand -- and leave an aluminum plate bearing the names of US filmmaker Steven Spielberg and British science fiction author Arthur Clarke among 880,000 people from 149 countries.

The spacecraft released the ball 40 meters (yards) away from Itokawa asteroid at 5:30 am (2030 GMT) as planned and then moved to 17 meters from the surface, an official of the Japan Aerospace Exploration Agency said.

Shortly after that, however, Hayabusa suffered a glitch and was not able to confirm its altitude, temporarily losing contact with the Earth.

The spacecraft resumed its signal transmission at 9:30 am (0030 GMT), but the agency could not confirm its position, the official said.

"We don't know whether the target marker landed on the surface," the official said, referring to the ball. "But we believe it did because Hayabusa moved to the 17-meter point from Itokawa after the release."

"We don't know yet whether Hayabusa touched down on Itokawa or extracted samples," he said.

The spacecraft is scheduled to try another touch-down on Friday and take samples from the asteroid.

Last Saturday, the agency lost contact with a micro rover released from Hayabusa after the small robot failed to land on the asteroid.

The lander, called Minerva and weighing less than 600 grams (21 ounces), was designed to investigate the surface of the asteroid with three small color cameras.

Hayabusa, the first spacecraft to bring home raw material from an asteroid if all goes well, was launched in May 2003 with a budget of 12.7 billion yen (just over 100 million dollars) and is scheduled to return to Earth in June

Japan's space program has been eyeing more ambitious projects after the humiliating failure in November 2003 to launch a spy satellite.

In February, Japan sent a weather satellite into space, its first launch since the 2003 failure when the satellite had to be destroyed 10 seconds after liftoff.

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