Returning Asteroid Probe Could Pave the Way for Manned Missions
Earth return of Japan's Hayabusa asteroid probe and release of its sample capsule.
Credit: C. Waste and T. Thompson (NASA/JPL-Caltech)

A piece of asteroid may be returned to Earth by a spacecraft for the first time when Japan's Hayabusa asteroid probe lands Sunday. Only after mission specialists get their hands on the craft will they know if the effort succeeded, however.

If the craft is packing some space-rock bits, the mission could help NASA figure out what to expect when it sends humans to an asteroid - a goal of President Barack Obama's new plan for NASA.

President Obama announced this vision while visiting NASA's Kennedy Space Center in Florida in April.

"By 2025, we expect new spacecraft designed for long journeys to allow us to begin the first-ever crewed missions beyond the Moon into deep space," ?President Obama said. "We?ll start by sending astronauts to an asteroid for the first time in history."

If Hayabusa manages to deliver a piece of asteroid rubble to Earth, that goal could be a step closer.

The Japanese probe is set to complete its seven-year mission Sunday when its sample-return canister lands in the Woomera Prohibited Area of South Australia. [Graphic:? How Japan's Hayabusa Asteroid Mission Worked]

The spacecraft visited the Itokawa asteroid in September? 2005. The probe landed and attempted to dig up a rock sample to take back to Earth. Though the procedure didn't go as planned, scientists still hope it was able to snag at least some asteroid dust in its sealed sampling chamber.

If it was successful, the material would be the first bit of asteroid that's ever been brought back to Earth by a robotic mission.

"A sample that you can bring into the lab can provide such a wealth of data that's very hard to get with robotic missions [that don't return to Earth]," said Peter Jenniskens of the SETI Institute in Mountain View, Calif. "The instruments on Earth in the lab are so much more refined."

Jenniskens is principal investigator of a NASA project to observe the spacecraft's plummet down to Earth from the vantage point of a Douglas DC-8 aircraft to study how well its heat shield protects it from the fiery heat of reentry.

Asteroids are interesting for a number of reasons. Studying them could tell us more about how the solar system formed and evolved, and might even shed light on how life got started on Earth, since some of the ingredients for life are thought to have been deposited on our planet by meteorites (which are asteroids that land on Earth).

In addition to providing a wealth of new science, a human mission to an asteroid could be a good practice ground for an even more ambitious manned spaceflight.

"The whole point of the current Obama program is to get to Mars with humans, and near-Earth asteroids are thought to be a stepping stone," said NASA's Don Yeomans, the U.S. project scientist for the Hayabusa mission.

Finally, asteroids might have reserves of water locked up in their rock. This would be interesting scientifically, since if life exists anywhere else in the universe, it would likely require water to survive. Moreover, a known source of water in space could be useful for breaking down into components for fuel for space missions.

"These could be the watering holes and fueling stations for future interplanetary travel," Yeomans told SPACE.com.

While helping to pave the way for a manned trip wasn't a primary goal of the Hayabusa mission, it might be an especially beneficial result.

"Hayabusa wasn?t sent out there to be a stepping stone type object for human exploration, but it certainly is going to provide a lot of characterization and information," Yeomans said.

However, that will all depend on just what exactly the spacecraft managed to pick up during its jaunt to Itokawa. Scientists are trying not to get their hopes up for an intact piece of the asteroid, since "it's not altogether clear that there will be a sample," Yeomans explained. "The hope is that there will at least be some dust particles inside."

Editor's Note: This article was corrected to reflect the fact that if Hayabusa succeeds, the material it brings back would be the first from an asteroid, not the first of any sort of rock from space (lunar rocks have been returned to Earth).