Spacecraft Gets 1st Peek at ‘Rubble Pile’

The Japanese spacecraft Hayabusa has found the first example of a “rubble pile” asteroid about 180 million miles from Earth.

The findings, published in the current issue of the journal Science, show that the asteroid Itokawa is a floating pile of loosely packed rock and dust shaped like a sea otter.

Rubble pile asteroids -- loose accretions of dust and rock broken up by collisions with other objects in space -- are thought to be the most common type in the near-Earth environment. Until now, though, only solid rock asteroids had been found.

“Although it is still unknown why these other asteroids do not show a rubble pile structure, at least now we have the first example of a rubble pile asteroid,” said Akira Fujiwara of the Japanese Aerospace Exploration Agency, or JAXA.

Hayabusa, which means “falcon” in Japanese, was launched in May 2003 on a nearly three-year journey to rendezvous with Itokawa, which is about 1,640 feet long.

Problems plagued the mission, the primary goal of which was to do a “touch-and-go” landing on the asteroid to collect dust from its surface and return to Earth. First, two of three gyroscopes failed. Then, the craft apparently failed to fire a small metal projectile into the surface of the rubble pile to kick up dust during its two brief landings.

Japanese scientists said they hoped enough dust was stirred up for collection.

“We just won’t know until Hayabusa comes back to Earth and we open it up,” JAXA spokesman Seiji Oyama said in December.

The craft is due to return in 2010.