TOKYO (AP) -- Japan's space agency said Tuesday it had re-established partial contact with a problem-plagued probe sent to collect samples from an asteroid, but a fuel leak could cut communications again.

The Japan Aerospace Exploration Agency said it had established sufficient contact with the Hayabusa probe to assess its condition and position.

JAXA has been gradually restoring communications with Hayabusa since January, after a thruster malfunction the previous month put the probe into a spin that caused a break in contact, the agency said in a statement.

It said it now has learned that a fuel leak that also occurred in early December apparently caused Hayabusa to lose most of the fuel for the chemical engine controlling its positioning.

The agency plans to use solar batteries to charge up an ion engine in order to control the probe's attitude and keep it properly oriented to maintain communications with Earth, but contact could be lost again if the operation fails, it said.

Launched in May 2003, Hayabusa's mission was to land on the asteroid Itokawa and collect samples to bring back to Earth. However, JAXA experienced a series of problems with the probe as it neared its destination.

JAXA lost contact with Hayabusa during a faulty touchdown in November and did not even realize the probe had landed until days later -- long after it lifted off the asteroid.

Hayabusa made a second landing days later but experienced trouble with its thruster after takeoff, forcing JAXA to shut down the probe's engines.

In addition, data from the probe did not show that it had fired a metal projectile onto the asteroid's surface during landing, as previously believed. The probe was to have collected dust particles shot up by the projectile's impact.

If Hayabusa does return to Earth with extraterrestrial material, it would be the first successful mission to bring back asteroid samples from space, JAXA said. A 2001 NASA probe of the asteroid Eros did not collect surface samples.

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