Japan's new asteroid probe reaches target after 3.2 billion km journey | Science

SAGAMIHARA, JAPAN-After 3.2 billion kilometers traveled in space, the Japanese satellite Hayabusa2 has officially arrived at the asteroid and will land later in the year to collect soil samples and surface rocks and subsurface and hopefully badyze them. The results should shed light on the materials that existed in the early solar system and the formation and evolution of the planets and their arrangement. They could provide evidence of the theory that asteroids and comets are a source of water from the Earth and its amino acids – the building blocks of life.

The ground crew in Japan confirmed this morning that Hayabusa2, launched in December 2014, has reached its original position 20 kilometers from Ryugu, an asteroid in orbit between Earth and Mars. "I'm really happy," said Yuichi Tsuda, project manager at the Institute of Space Science and Astronautics (ISAS) of the Japan Aerospace Exploration Agency in Sagamihara, during a meeting. a press conference on the ISAS campus. afternoon.

Over the next 18 months, this second edition of Hayabusa, in Japanese for the Peregrine Falcon, will move around the asteroid, while a suite of instruments will map it; measure its mbad, density and gravity; determine its mineral and elemental composition; and locate the landing sites. The first of a series of landings is scheduled for October. In addition to collecting surface soil samples, Hayabusa2 will launch a Franco-German rover called MASCOT that will leap across the surface, using its four instruments to badyze soil samples in situ.

Next spring, Hayabusa2 will blow up a crater in the Ryugu using a 2-kilogram projectile with a hardened copper nose moving at 2000 meters per second. (To avoid the damage caused by the scattering of debris, the spacecraft hides on the opposite side of the asteroid after releasing the projectile and using a camera to document the collision.) The images of the impact should illuminate the formation of craters on the celestial bodies. Hayabusa2 will then return to the site of the explosion to collect samples of rocks that have not been subjected to eons of space, hopefully giving a glimpse of the material as it is. He was during the formation of the solar system. The gear is expected to return its samples to Earth by the end of 2020.

Seiichiro Watanabe, a project scientist at Nagoya University in Japan, said, "The preliminary observations are really exciting. The diamond-shaped asteroid is about 900 meters in diameter and rotates around its own axis every 7.5 hours or so, more slowly than other similarly sized asteroids for reasons that are not yet clear, says Watanabe. The surface is dotted with rocks larger than what one would expect to have accumulated on an asteroid of its size, which sparked a debate among planetary scientists. One line of thought is that Ryugu was originally part of a larger asteroid that broke up. But others claim that the rocks could have landed with time or could have been hard mbades incorporated into the asteroid at its formation and exposed later as softer eroded materials. "It's a strange phenomenon," says Watanabe.

This is ISAS 'second mission to recover samples from an asteroid. The original Hayabusa, launched in 2003 to explore an asteroid named Itokawa, "was a stunning success," the global scientist Erik Asphaug at the University of California, Santa Cruz, wrote in a commentary on Science In June 2006, despite engine failures, an impressive array of mechanical failures, fuel and solar losses, and communications failures over a seven-year, six-billion-kilometer odyssey. The return sample capsule, which landed in the Australian outback in June 2010, was carrying 1500 particles of asteroid dust, despite problems with the sample collection mechanism. And even before Hayabusa landed on Itokawa, he had returned enough data for scientists to publish a Science, including a conclusion that the asteroid was a loose agglomeration of rubble rather than a solid rock.

Hayabusa2 will provide complementary data, especially because it lands on a C-type asteroid or carbonaceous; Itokawa is an asteroid of type S or siliceous. The C-type asteroids populate the outer regions of the asteroid belt that extends between the orbits of Mars and Jupiter, where the distance from the sun might have retained water as well as amino acids . S-type asteroids are usually closer to where high temperatures would have burned out of the water. Additional data on the C-type asteroids will come from NASA's OSIRIS-REx satellite, currently en route to the asteroid Bennu, where it will collect samples and bring them back to Earth in 2023. The two teams will exchange some of their samples. "It has been an international collaboration since the beginning of development," says Tsuda.