More than a year, Japan’s Hayabusa2 spacecraft has been hanging around the asteroid Ryugu, dropping off robots, furthermore blasting the surface with metal slugs. The (JAXA) Japanese Space Agency hopes to bring Hayabusa2 and its valuable cargo of asteroid samples home soon, however first, there’s just one more robot to deploy.
Hayabusa2 carried some robots with it to Ryugu, and JAXA confirms the spacecraft launched its final robotic explorer last night. The Minerva-II2 rover started its descent from an altitude of about 1 kilometer (0.6 miles); however, it won’t reach the surface till early next week. After releasing the lander, Hayabusa2 moved again up to a higher orbit to observe the robot’s progress.
The initial round of robotic explorers consisted of Minerva-II1A, including Minerva-II1B; however, they were not quite rovers. These drum-shaped robots had motors that let them hop alongside the surface, taking images and gathering temperature data along the way. This helped JAXA perceive the structure of Ryugu, which was much more uneven than they had anticipated. In late 2018, Hayabusa2 dropped another robot known as MASCOT. This robot used an identical method of moving around the surface; however, it was box-shaped and had no solar panels. It has only 16-hour battery power.
Minerva-II2 is the third distinct kind of robot aboard Hayabusa2. It’s mobile, however calling it a “rover” is a bit misleading. Minerva-II2 is drum-shaped, just like the previous Minerva explorers; however, it’s bigger than they were. The picture above shows the descent module containing Minerva-II2, and below, you can see what the robot’s appearance.
JAXA previously reported possible issues with Minerva-II2’s CPU. That may prevent it from relaying data to the spacecraft; however, there’s no harm in the try at this point. Hayabusa2 has accomplished its primary mission, using tantalum slugs to launch materials from the surface of Ryugu into its sample collection compartment. Even if Minerva-II2 doesn’t work, Hayabusa2 can set course for Earth in the coming weeks with a wealth of data about Ryugu. The sample container should land on Earth in late 2020, permitting scientists to study material from an asteroid that hasn’t been scorched in the atmosphere for the first time.