A few hours ago the Hayabusa 2 space probe was launched on a H-IIA 202 rocket from the Yoshinobu Launch Complex at the Tanegashima center run by JAXA, the Japanese space agency. After almost two hours Hayabusa 2 successfully separated from the rocket’s last stage starting its long voyage towards the asteroid (162173) 1999 JU3.
The Hayabusa 2 mission follows the previous mission Hayabusa, whose name means peregrine falcon, which was launched on 9 May 2003. It reached the NEO (Near-Earth Object) asteroid 25143 Itokawa in September 2005. It came down to the asteroid, not in a real landing but rather touching down to collect some samples to bring back to Earth. The Hayabusa space probe also had a small lander called Minerva that was supposed to make a real landing but the maneuver failed and it escaped the asteroid’s weak gravity.
Various technical problems to the Hayabusa space probe’s gyroscopes and other systems almost derailed the mission. For some time JAXA lost contact with Hayabusa, increasing the risk for a probe in less than optimal conditions during a pioneering mission. Instead, not only JAXA regained control of Hayabusa but in June 2010 the capsule containing the asteroid Itokawa’s samples was recovered and the dust was analyzed.
In 2003, when the Hayabusa mission was underway, JAXA obtained the approval for a sequel, which became Hayabusa 2. This space probe is an evolution of the first one with more advanced systems that should increase the chances of its success. After the failure of the lander in the first mission, this time the probe carries three Minerva landers similar to the lost one.
This is still a Japanese mission but in 2013 a collaboration was announced with the space agencies of Germany (DLR) and France (CNES), which designed and built the MASCOT (Mobile Asteroid Surface SCOuT) lander. It’s derived from studies carried out by these agencies while working with ESA on the Philae lander but also from those for the Marco Polo mission, a collaboration between ESA and JAXA to land on an asteroid in a project then abandoned.
The target for the Hayabusa 2 mission is the (162173) 1999 JU3 asteroid, which has an almost spherical shape with a diameter of little more than 900 meters (a little more than 3,000 feet). It belongs to the Apollo class, a group of NEO-type asteroids whose semi-major axis is greater than Earth’s and a perihelion lower than the Earth aphelion. This very technical definition indicates potentially dangerous objects because their orbit crosses that of our planet.
The arrival of the Hayabusa 2 space probe is scheduled for July 2018. It’s planned to spend a year studying the asteroid (162173) 1999 JU3, collect samples from its surface, leave and return to Earth in December 2020.