In 2014, the Japanese Aerospace Exploration Agency (JAXA) launched the Hayabusa 2 spacecraft on a four year journey to Ryugu, an asteroid nearly 200 million miles from Earth. The spacecraft has been in orbit around the asteroid since June and early Friday morning dispatched two rovers to the asteroid’s surface.
The confirmation of these rovers’ safe landing will mark the first time that a maneuverable robot has landed on the surface of an asteroid.
The two JAXA rovers, named MINERVA-II1 A and B, navigate using a “hopping” mechanism. Using a more traditional form of locomotion such as wheels or crawlers was impossible because the gravity on Ryugu is so weak. As soon as the rover with wheels started moving, it would’ve began floating upwards. According to JAXA, when the robots hop, they stay in the air for up to 15 minutes at a time and can move around 40 feet per hop.
The first time a spacecraft landed on the surface of an asteroid was in 2001 when NASA’s NEAR mission touched down on Eros. Since then, several missions have been deployed to asteroids and comets, but none of the landers have had the ability to move once they touched down on the surface.
The two robots have a total of seven cameras between them, which they will use to create a stereo image of Ryugu’s surface. Later in the mission, Hayabusa 2 will dispatch a third MINERVA-II rover to the asteroid’s surface as well as the MASCOT lander developed by Germany and France.
Before Hayabusa 2 departs the asteroid, it will fly close to its surface with a sampling horn and fire a small bullet into the asteroid to collect the particles that are ejected during impact. To get a deeper asteroid sample, the spacecraft will also drop a small explosive charge to the surface and a camera will capture the explosion on video. The spacecraft will have to wait for nearly two weeks for the debris from the explosion to settle, at which point it will descend into the explosion crater, collect a sample and then begin its return journey to Earth. Hayabusa 2 is expected to return to Japan in late 2020.