Bringing Japan's most complex space mission near its climax, a probe is within 12 miles of an asteroid almost 180 million miles from Earth in an unprecedented rendezvous designed to retrieve rocks from its surface.
The Hayabusa probe, launched in May 2003, will hover around the asteroid for about three months before making its brief landing to recover the samples in early November. The asteroid is located between Earth and Mars.
"The mission is going very smoothly and proceeding as planned," Atsushi Wako, a spokesman for JAXA, Japan's space agency, said Tuesday.
The asteroid, informally named Itokawa, after Hideo Itokawa, the father of rocket science in Japan, is only 2,300 feet long and 1,000 feet wide, and has a gravitational pull one-one-hundred-thousandth of Earth's.
Though it took two years to get there, the asteroid is among the closest neighbors to Earth other than the moon.
The probe's first mission will be to survey the asteroid with cameras and infrared imaging gear. It has already begun sending back images, Wako said.
When Hayabusa moves in for the rendezvous, expected to be over in a matter of seconds, it will pull up close enough to fire a small bullet into the asteroid and collect the ejected fragments in a funnel-like device. It won't be coming back with much -- the amount of material planners hope to capture wouldn't even fill a teaspoon.
JAXA officials say Hayabusa would be the world's first two-way trip to an asteroid. A NASA probe collected data for two weeks from the surface of the Manhattan-sized asteroid Eros in 2001, but it did not return with physical samples. No samples have been brought back to Earth from a space mission since the U.S. Apollo moon project in the 1970s.
Despite a glitch with one of Hayabusa's three gyroscopes, the mission has been largely mishap-free. Wako said the probe is set to return to Earth and land in the Australian outback in June 2007.
The success of the mission so far is a major coup for JAXA.
Japan was the fourth country to launch a satellite, in 1972, and this spring announced a major project to send its first astronauts into space and set up a base on the moon by 2025.
JAXA already has an unmanned moon survey mission planned. Its SELENE probe -- originally scheduled for launch in 2005, but since delayed -- is designed to orbit the moon, releasing two small satellites that will measure the moon's magnetic and gravitational field and conduct other tests for clues about the moon's origin.
It had to abandon a mission to Mars two years ago, however, after the probe moved off course. The explosion of a domestically designed H-2A rocket, the centerpiece of the country's space program, in November 2003 also marked a major setback for JAXA's plans. Controllers had to detonate that rocket and its payload of two spy satellites after a booster failed to detach.
The failed launch came just one month after China successfully put its first astronaut into orbit. Beijing has since announced it is aiming for the moon.
Japan returned to space in February with a successful H-2A launch, after 15 months on the ground.