Possible Asteroid Particles Found in Returned Space Probe

Japanese space officials have found intriguing dust-like particles inside the sample capsule from the asteroid probe Hayabusa, but whether they are actually pieces of an asteroid or contamination from Earth remains to be seen, Japan's space agency announced Tuesday.

The tiny particles were discovered after scientists opened the Hayabusa probe's sample container, which returned to Earth on June 13 after a seven-year journey to the asteroid Itokawa. Scientists began opening the capsule on June 24, officials with the Japan Aerospace Exploration Agency (JAXA) said.

"The fact is that the JAXA scientists found some particles in the sample container and the sample catcher," JAXA spokesperson Makoto Miwada told SPACE.com. [Photos of the asteroid probe's particles.]

In a Tuesday statement in English, JAXA officials said scientists are unsure if the particles are asteroid samples or contamination from Earth. The announcement came after earlier Japanese news reports stating that trace gases had also been found inside the capsule.

Japan's Hayabusa mission was an ambitious expedition to return the first-ever samples of an asteroid back to Earth. The robotic spacecraft launched in 2003, but suffered several failures ? including malfunctions with its sample collection devices.

The Hayabusa probe landed on Itokawa twice in 2005 in attempts to collect asteroid samples. Mission scientists hoped that at least some bits of the asteroid Itokawa, a silicon-rich space rock, managed to fly inside the spacecraft's sample capsule for return to Earth. This graphic shows how the Hayabusa asteroid mission worked.

Miwada said the particles found inside the capsule's sample container and sample catcher show up clearly in two photographs released by JAXA.

"We can see some gray particles and some white ones," Miwada said in an e-mail of sample container material. "Scientists believe them as particles or dust that came in during the ground operations or inside the spacecraft, though they are going to analyze the particles carefully comparing with the ground dust samples."

More particles were found inside one of the chambers of Hayabusa's sample catcher, another part of the probe's asteroid sampling system.

Two tiny particles, each just 10 micrometers in size, were discovered inside Chamber A of Hayabusa's sample catcher, Miwada said. The chamber was used during the probe's second landing on asteroid Itokawa.

And these particles are expected to be just the beginning, JAXA officials said.

"Scientists are continuing [the] survey of Chamber A for some weeks, followed by the survey of Chamber B," Miwada said. "So we expect much more particles."

The Hayabusa sample capsule is being studied at a JAXA facility in Sagahimara, Japan, where scientists are cautiously working to open the capsule and search for particles while avoiding any chance of contamination.

"The Japanese are conducting this sample extraction process rather slowly ? as they should," Don Yeomans, NASA's project scientist for the Hayabusa mission, told SPACE.com recently.

Researchers hope that any samples of the asteroid Itokawa inside Hayabusa's sample container could offer new insights into the composition and other characteristics of space rocks throughout the solar system.?

• Photos: Japan Asteroid Probe's Fiery Landing, Video
• Graphic: How Japan's Hayabusa Asteroid Mission Worked
• 5 Reasons to Care About Asteroids