The Japanese space probe Hayabusa 2 has exposed another exploration robot over the asteroid Ryugu. The drum-shaped device called Minerva-II-2 is to collect data on the density of the celestial body; the probe dropped it a kilometer above the asteroid. Over the next five days, Minerva-II-2 will now circle eight times around Ryugu's equator and then touch down on the surface. This was reported by the Japanese space agency Jaxa.

Tohoku University, the German Aerospace Center (DLR) and the French space agency CNES are involved in the mission. The researchers want to track down the origins of the solar system with the mission to the asteroid, which is currently 250 million kilometers from Earth.

The release of Minerva-II-2 is the last exploration to start from Hayabusa 2. In November and December, the probe is expected to leave the asteroid and return to Earth by the end of next year.

Soil samples from Ryugu

Hayabusa 2 was launched in December 2014 in Japan and had reached its goal at the end of June last year. A few months later, the probe released the first two Minerva II series robots. They landed as a vanguard of the lander Mascot on Ryugu and took pictures of its surface. They were followed by Mascot, who explored Ryugu for several hours.

Minerva-II-2 was also supposed to have explored the surface of Ryugu, but due to technical problems, the scientists had to change the mission. Now the main task of the robot is to collect data on Ryugu's magnetism. In the meantime, the mother probe Hayabusa 2 will take pictures at a distance of eight to ten kilometers above the asteroid.

Hayabusa 2 itself had landed on Ryugu in February and had collected samples from the surface. In July, she started again - this time to take samples from below the surface. That had never happened before.

Scientists suspect that the material contains traces of the time when the solar system was formed some 4.6 billion years ago. It could contain organic molecules as well as water. Asteroids like Ryugu could also have brought water to our planet during impacts on Earth. A predecessor model of Hayabusa 2 had brought soil samples of an asteroid to earth in 2010 for the first time.