EDITORIAL: Hayabusa probe returns

Japan's asteroid probe Hayabusa will return to Earth on June 13 after seven years in space. Although the main body of the probe will be incinerated as it re-enters Earth's atmosphere, the detached capsule is expected to land in the Australian desert.

This should represent a big step for Japan's space technology.

The return of Hayabusa is significant not only for its successful round trip, but also because the capsule is expected to contain samples of an asteroid's surface, a world first. We look forward to the Hayabusa's safe return and the studies on the samples.

The probe was launched in May 2003. After traveling 2 billion kilometers, it reached its destination, the asteroid Itokawa, in autumn 2005. The asteroid is about 500 meters in diameter and is shaped like an elongated peanut with a bumpy surface.

The asteroid is believed to retain substances that helped to form the planets when the solar system was born. The surface samples should provide precious clues about the history of our solar system.

The images photographed by Hayabusa, as well as the survey results of the asteroid's composition, amazed scientists around the world. The U.S. magazine Science even published a special Hayabusa issue.

The American forerunners of planetary survey missions lavished Hayabusa with the highest possible praise. Even if the photos and survey analyses are the only things Hayabusa sent back, those alone would be truly worthy of accolades, they said.

Hayabusa was supposed to have collected the samples by shooting a bullet into the asteroid's surface the moment it landed and capturing the dust particles that floated up. But officials said the bullet did not eject properly. They hope the spacecraft caught the dust that rose upon the impact of the landing.

Hayabusa weighs 510 kilograms. It is a little larger than a standard refrigerator, and contains numerous instruments.

Its mission was not just about observation, but also about testing new engines and the autonomous navigation system for future full-fledged survey missions.

Hayabusa, which can be described as a highly sophisticated robot, could not constantly wait for instructions from Earth because a radiowave takes 40 minutes to complete a round trip between our planet and Itokawa.

Hayabusa had to monitor Itokawa's surface with its camera while autonomously conducting such tasks as observing, approaching and landing.

The probe must have reminded the world that robotics are indeed Japan's stock-in-trade.

But during the long journey, one component after another broke down, leading a specialist to say, "It is a miracle that it moves at all."

At one point, communications were disrupted for seven weeks. It was just one of the many desperate situations involving Hayabusa.

However, the probe team at the Japan Aerospace Exploration Agency dealt with each crisis by creatively using the remaining tools to their utmost capacity. As a result, Hayabusa managed to return home, albeit three years later than scheduled.

The space program requires huge amounts of money, and the array of potential projects is wide.

What would be most effective for Japan's space program? The success of Hayabusa, which used Japan's original techniques and ideas, may well give us a clue.

--The Asahi Shimbun, May 10