TOKYO, Japan (Reuters) -- A Japanese space probe apparently succeeded in landing Saturday on an asteroid and collecting surface samples in an unprecedented mission to bring the extraterrestrial material back to Earth, but afterwards showed signs of trouble, Japan's space agency said.The probe, now hovering about 5 kilometers (3.1 miles) from the asteroid, appeared to be shaking vertically due to problems with its thruster, according to spokesman Atsushi Akoh of Japan's space agency JAXA. The agency would put the probe into "safety mode" to investigate, Akoh said. The Hayabusa appeared to have touched down for a few seconds on the asteroid -- floating 290 million kilometers (180 million miles) from Earth -- to collect powder from its surface before lifting off again to transmit data to mission controllers, according to spokesman Kiyotaka Yashiro of Japan's space agency, JAXA. More data confirming the mission's success is expected later in the day after scientists have examined additional transmissions from the probe, Yashiro said. But JAXA will not know for sure if Hayabusa collected surface samples until it returns to Earth. It is expected to land in the Australian Outback in June 2007.If all goes well, it will be the first time a probe returns to Earth with samples from an asteroid, according to JAXA. A NASA probe collected data for two weeks from the asteroid Eros in 2001, but did not return with samples. Saturday's landing on the asteroid was Hayabusa's second, following a faulty touchdown Sunday. JAXA lost contact with the probe during that attempt and did not even realize it had landed until days later -- long after Hayabusa had lifted off into orbit. The space agency hopes 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 larger bodies such the planets or moons. Hayabusa fired a metal projectile shortly before 8 a.m. Japan time (11 p.m. GMT), suggesting that the asteroid had landed and collected the dust that was kicked up. The whole procedure was over in a matter of seconds, as planned. "It is only a very small amount of material, powder really," Yashiro said. The landing could compensate for a series of glitches in Japan's attempt to complete the world's first two-way trip to an asteroid. Two rehearsal touchdowns were botched, one when the spacecraft had trouble finding a landing spot, and one when a small robot rover was lost in space. Hayabusa also had a problem with one of its three gyroscopes. Hayabusa was launched in May 2003 and has until early December before it must begin its journey home. On top of recovering samples from the Itokawa asteroid, the probe is also testing a new type of ion engine that uses an electric field to accelerate positive ions to a high velocity. It swung by Earth for a gravity assist that propelled the probe toward Itokawa, JAXA said on its Web site. JAXA hopes to use the fuel-saving technology in missions further into outer space, the Web site said. The potato-shaped asteroid is named after Hideo Itokawa, the father of rocket science in Japan, and is orbiting the sun between Earth and Mars. It is 690 meters (2,300 feet) long and 300 meters (1,000 feet) wide. Copyright 2005 Reuters. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.