Scientists Eager To See if Hayabusa Returned Asteroid Sample


NEW YORK — The June 13 landing of a Japanese space capsule that visited an asteroid and returned to Earth despite near-overwhelming malfunctions now has scientists around the world asking one question: Did it actually capture a piece of the asteroid Itokawa?

“First, the sample container will be inspected, and then the content will be extracted,” Keiji Tachikawa, president of the Japan Aerospace Exploration Agency (JAXA), said in a statement Monday. “We hope to find the Itokawa’s surface material in the capsule, and contribute to understanding the origin and evolution of the solar system.”

Japan’s 510-kilogram Hayabusa asteroid probe lit up the night sky as it re-entered the atmosphere above the remote Woomera Prohibited Area in the Australian Outback.

The spacecraft’s sample return capsule, which separated as planned three hours before re-entry, appeared as a bright light leading the main fireball created by the demise of its mother ship.

The dazzling spectacle was a fiery finale for the Hayabusa probe, but just the beginning for scientists on Earth.

Hayabusa’s sample return capsule, a 40-centimeter container about the size of a basketball, survived re-entry using a heat shield and successfully parachuted to the Earth’s surface. It has since been recovered by JAXA scientists.

But it is unclear if Hayabusa’s sample capsule contains traces of the asteroid Itokawa.

“The hope is that there will be at least some dust particles inside the space capsule,” said Don Yeomans, the U.S. project scientist for the Hayabusa mission.

Japan launched the $200 million Hayabusa mission in 2003, and it reached the asteroid Itokawa in 2005, landing multiple times in attempts to capture samples. But the probe’s projectile device designed to kick up samples so they could be collected failed to work properly.

Yeomans said that scientists know Hayabusa’s target asteroid Itokawa is a silicon-rich space rock with the consistency of a rubble pile. But actual samples, however small, will give researchers concrete evidence of the fundamental characteristics for such asteroids.

“Even if only a couple of particles much smaller than a grain of sand were collected, we would be able to get more information,” Yeomans said.

For now, scientists will have to wait until the Hayabusa sample capsule makes one last journey from the Australian Outback to JAXA’s Sagamihara Campus in Kanagawa, Japan. Only then will the capsule be opened in a clean room to reveal if it captured the first sample of an asteroid.

In addition to its asteroid mission, Hayabusa has already contributed to a different branch of space science.

An international team caught the spacecraft’s re-entry on video from a NASA chase plane as part of an experiment to study how spacecraft heat shields perform during re-entry. Hayabusa’s heat shield, too, was later recovered.

“It was incredibly fortuitous to see the capsule and bus so well separated. We got data on both phenomena,” said Peter Jenniskens, a researcher from the SETI Institute in Mountain View, Calif., who led a NASA-sponsored observation campaign. “For years to come, this video will serve as a demonstration of why we build thermal protection systems, as it shows the capsule surviving the entry and the unprotected rest of the spacecraft being torn apart by thermal and mechanical stresses.”