Capsule plunges to Earth after historic visit to asteroid
BY STEPHEN CLARK
Posted: June 13, 2010
Updated @ 11:15 a.m. EDT
Updated @ 1:10 p.m. EDT
Cutting across the night sky at more than 27,000 mph, a small Japanese capsule returned to Earth from the surface of an asteroid Sunday and landed in the remote Australian outback.
Streaming video from Australia showed a luminous fireball appear in the sky near the correct position, indicating the Hayabusa craft was on track toward a touchdown in the Woomera Prohibited Area in South Australia around 1411 GMT (10:11 a.m. EDT), or 11:41 p.m. local time.
A fleet of all-terrain vehicles and helicopters were standing by at Woomera, a military installation in the Australian outback. More than 50 representatives of the Japan Aerospace Exploration Agency joined several dozen Australian workers to recover the Hayabusa capsule.
The recovery teams detected the capsule's beacon signal and a helicopter located the downed craft in the expected landing zone at 1456 GMT (10:56 a.m. EDT).
Officials plan to retrieve the capsule by Monday afternoon, Australian time.
The capsule was programmed to dive into the atmosphere at an angle of approximately 10 degrees, braving temperatures of nearly 5,000 degrees Fahrenheit during the moment of peak heating.
A carbon fiber heat shield was designed to protect the craft from the destructive heat.
The capsule was supposed to jettison a portion of its heat shield and backshell once it reached a point 6 miles above Earth, permitting its parachute to unfurl and slow the craft to a more gentle velocity.
Hayabusa's main spacecraft also plummeted back to Earth just a few miles behind the capsule, but it burned up during re-entry as expected.
The Hayabusa mothership spring-ejected the drum-shaped return capsule at 1051 GMT (6:51 a.m. EDT) as the craft traveled more than 25,000 miles above the planet. Hayabusa put the capsule in a slow spinning motion before separation to keep the uncontrolled container stable and thermally condition its battery.
Japanese officials last communicated with the Hayabusa probe at 1328 GMT (9:28 a.m. EDT) as it passed out of range of ground stations. A rush of applause, smiles and handshakes went through the control room around the same time.
Sunday's fiery return to Earth wrapped up a mission lasting seven years and traversing more than a billion miles across the solar system.
Hayabusa launched in May 2003 and reached asteroid Itokawa in September 2005 for three months of research and daring close approaches to the potato-shaped object. The visit ended with a series of attempts to collect samples from the asteroid, but the spacecraft inadvertently landed on the surface for 30 minutes.
Telemetry analysis after two touchdowns on Itokawa showed Hayabusa likely did not fire a projectile into the asteroid's gravely surface, but Japanese scientists are hopeful light amounts of dust could have moved into the funnel leading to the sample container.
Officials won't know for sure until the capsule is flown back to Japan and moved into a special curation facility at the Sagamihara campus on the outskirts of Tokyo. That could occur as early as Tuesday or Wednesday.
Researchers will take their time examining and opening the container.
"Opening the capsule will take place within a few weeks of arrival here," Kawaguchi said in an interview from Sagamihara. "We must take the utmost care to open the capsule. It takes a lot of time to study the samples because they will probably be in fine particles."
Scientists must also distinguish between contamination from Earth and particles from the asteroid, and that could take several months.
Hayabusa missed an opportunity to come home in June 2007, but the probe finally fired its ion propulsion system to begin the journey back to Earth.
The spacecraft was stymied by a major fuel leak, the failure of two-thirds of its attitude control system, the loss of three of its four ion engines, and trouble with its primary battery.
The problems put the mission in doubt many times, and Kawaguchi remained publicly pessimistic about Hayabusa's chances until the final days before re-entry.
"We have been quite lucky in succeeding and continuing this mission," Kawaguchi said last week. "I personally am very proud of the teams, comprised of the engineers and the scientists who continue to do these activities."
"We've just been lucky."