Japan’s Hayabusa2 spacecraft has arrived at its target asteroid, Ryugu, after a journey of nearly 2bn miles (3.2bn km), which has taken three and a half years to accomplish. The spacecraft is now tracking the 900-metre-wide asteroid, from about 12 miles above its surface. Following analysis while in orbit, Hayabusa will begin a series of touchdowns on Ryugu this autumn.
During these manoeuvres the spacecraft will collect surface samples. It will also release a German-French rover, the MASCOT, which will hop across the asteroid.
Next year, Hayabusa will release a 4.4lb (2kg) projectile to strike the asteroid at just over a mile a second, forming a crater. The spacecraft will shelter from the impact on the opposite side of the asteroid, the event being recorded via a remote camera.
The images will let scientists witness crater formation firsthand, then allow the spacecraft to collect rock samples from the exposed material.
Built by the Japan Aerospace Exploration Agency (known as JAXA), Hayabusa2 was launched atop a Japanese H-2A rocket on 3 December 2014. It is the follow-up to the partially successful Hayabusa mission, which, in 2010, carried dust fragments from the asteroid Itokawa to Earth.