Scientists inside a spotless clean room near Tokyo are carefully opening the drum-shaped capsule from the Hayabusa mission, beginning months of tedious evaluations to determine whether the $200 million mission returned dust grains from an asteroid.

Hayabusa is being examined at JAXA's curation facility in Sagamihara, Japan. Credit: JAXA

In a press release issued Thursday, the Japan Aerospace Exploration Agency said it will take about a week to fully open the canister inside the 16-inch-wide re-entry capsule that landed June 13 in the Australian outback.

Assisted by NASA representatives, Japanese scientists are opening the capsule in an ultra-clean curation facility at JAXA's Sagamihara campus near Tokyo.

The craft was flown from Australia to Tokyo, then transported to Sagamihara on June 18.

An X-ray of the canister showed no sample grains larger than 1 millimeter, or about 1/25 of an inch, according to JAXA.

After cleaning the capsule and opening its outer shell, scientists measured a small amount of a trace gas from the cylindrical capsule buried deep inside the re-entry craft.

A diagram of the Hayabusa capsule. Credit: JAXA

Researchers are hopeful the gas came from asteroid Itokawa, the object of Hayabusa's seven-year mission that stretched nearly 4 billion miles across the solar system.

JAXA is analyzing the gas to determine what its made of and if it was picked up at the asteroid.

Hayabusa touched down on Itokawa twice during its survey of the asteroid in late 2005, but its sample collection system failed to activate as planned. The snafu means Hayabusa almost certainly did not gather large bits of rock from Itokawa, but JAXA officials believe some small grains of dust may have been funneled into the sample chamber in the microgravity environment.

Once the capsule is opened, scientists will pull the sample catcher from the craft and move it to an adjacent room in a special apparatus designed to limit the container's exposure to contaminants from Earth.

The Hayabusa re-entry capsule is about 16 inches wide. Credit: JAXA

It could take up to six months to retrieve samples from the canister. Most of the material will be microscopic grains needing extensive analysis to determine if they are from the asteroid or elsewhere.

Scientists plan to use a microscope and spectrometer to gauge the size, origin and chemical make-up of the samples.