A Japanese spacecraft is zooming in on a precious stone asteroid

It's been nearly four years since the Japanese spacecraft Hayabusa-2 took off, heading for a small asteroid that was then known only as 1999 JU3.

At the time, we did not have many details about 1999 JU3 – not even a good picture of the subject. But JAXA, the Japanese space agency, was still planning to visit it with Hayabusa-2, using explosives to blow up debris, pick up the dust of fresh asteroids and bring back its cargo to Earth, after depositing some mini-rovers on the floor. surface of the asteroid, of course.

The asteroid needed a better name. Finally, he reborn under the name of Ryugu, the name of the underwater palace of the dragon god in Japanese mythology. The hero of a Japanese legend visits Ryugu and returns with a precious cargo, a trajectory that the creators of Hayabusa-2 hope to emulate with greater success than the original mission of Hayabusa. While this mission back sample to an asteroid has managed to bring back a very small Asteroid dust sample in 2010, the mission encountered a host of obstacles and malfunctions.

Hayabusa-2 began its final approach towards Ryugu on June 3rd and the asteroid begins to focus. But it takes time to get a clear picture. In this image, taken on June 10 1,500 miles away, Ryugu is a blob of only 5 or 6 pixels in diameter.

On June 14, Hayabusa-2 was 700 km away and JAXA researchers were finally able to see the rotation of the asteroid, which is rotating retrograde in the opposite direction relative to the orbit of the planets around the Sun. It also revolved around its vertical axis.

As the spacecraft gets closer, more details emerge. The researchers found that Ryugu made a complete rotation every 7.5 hours, and found that its conical shape looked like a top. The director of the mission, Makoto Yoshikawa wrote: "When I saw these images, I was surprised that Ryugu looks a lot like the destination of the US OSIRIS-REx mission, to the asteroid Bennu and the target of the MarcoPolo-R mission by Europe, 2008 asteroid EV5. "Yoshikawa writes. "Until now, the asteroids that we explored were of different shapes, so Ryugu and Bennu could be the first time that two similarly shaped asteroids were examined.It will be interesting to clarify exactly what this similarity means scientifically. . "

NASA's OSIRIS-REx mission is expected to begin its approach to the asteroid Bennu in August of this year. Although they are on two separate calendars (OSIRIS-REx launched in 2016, and will spend a year studying the asteroid), a primary goal of both missions is to return a sample of an asteroid to Earth, a project scientists from each mission work closely together to share information.

In the most recent photo (seen at the top of this post), an even more detailed image is emerging, an angular shape in pocketed rotation of craters. Project leader Yuichi Tsuda compares the shape to the crystalline form of fluorite, which he says is known in Japanese as "firefly". The resemblance is rather strange.

Ryugu is technically classified as a potentially dangerous asteroid, but that does not mean you have to worry about it. As Ryan Mandelbaum points out in Gizmodo the designation "potentially dangerous" does not mean that an asteroid is likely to hit the Earth anytime soon. It could, may be at some point in the distant future, but it is followed and watched closely, so we would have a lot of warning if his way ended up crossing our own.

Researchers are interested in Ryugu because it is a class C asteroid, one of the most common types of asteroids. By analyzing materials from the space rock, scientists hope to better understand how the bodies of the solar system, from asteroids to planets, have developed.

Hayabusa-2 is expected to arrive in Ryugu on June 27, remaining about 20 km above the surface of the asteroid. If all goes well, he will gather his first sample between September and October.