The Hayabusa mission

The JAXA/Hayabusa mission was the first asteroid sample return in the world. The target asteroid was (25,143) Itokawa, a small (500 m of size) S-type near-Earth asteroid. Hayabusa, which was launched in May 2003, arrived at Itokawa in September 2005, offering the first opportunity to see a very tiny asteroid in detail. To our surprise, the asteroid surface did not show clear craters, but was covered by a lot of boulders. Hayabusa observed Itokawa by its four scientific instruments and tried to collect surface materials by touchdown twice. However, the touchdown operations were not executed as planned and Hayabusa had serious problems after the second touchdown. Nevertheless, Hayabusa successfully brought thousands of small grains from Itokawa back to the Earth in June 2010. We studied Itokawa in detail by both remote sensing data and returned samples, and we revealed a lot of new information to study its origin and evolution.