Japan's space agency has lost contact with a wayward probe that botched an attempted rehearsal landing in a mission to collect surface samples from an asteroid and return to Earth, an official said Monday.

The coffee can-sized Minerva robotic lander has been drifting above the asteroid since Saturday, when it was deployed from the mother probe Hayabusa, which is scheduled to attempt its own landings later this month.

Mission controllers can no longer contact Minerva nor control its movements, and are hoping the solar wind will guide the probe back to the potato-shaped asteroid Itokawa for a possible landing, space agency spokesman Kiyotaka Yashiro said.

"It didn't touch down and we're not sure where it will go," Yashiro said.

The loss is the latest glitch in Japan's attempt to complete the world's first two-way trip to an asteroid. A similar rehearsal touch down was aborted earlier this month when the spacecraft had trouble finding a landing spot.

JAXA, Japan's space agency, said the main probe was still on track for its own landings to collect surface material from Itokawa on Nov. 19 and Nov. 25.

It is hoped that examining asteroid samples will help unlock the secrets of how celestial bodies formed because their surfaces are believed to have remained relatively unchanged over the eons, unlike those of larger bodies such the planets or moons, JAXA said.

In preparation for Hayabusa's landings, Minerva had been expected to hop around on the asteroid's surface, collecting data with three small color cameras. Its loss does not seriously affect plans to land Hayabusa, Yashiro said.

Hayabusa was launched in May 2003 and has until early December before it must begin its 180 million mile journey home. It is expected to return to Earth in June 2007.

The asteroid is named after Hideo Itokawa, the father of rocket science in Japan, and is orbiting the sun between Earth and Mars. It is 2,300 feet long and 1,000 feet wide.

A NASA probe collected data for two weeks from the Manhattan-sized asteroid Eros in 2001, but did not return with samples.