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Japanese Mission Becomes First to Land Rovers on Asteroid

Twin probes from Hayabusa2 mission have sent back their first pictures from Ryugu’s surface

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Japan’s asteroid mission Hayabusa2 has become the first to land moving rovers on the surface of an asteroid.

On 22 September, the Japan Aerospace Exploration Agency (JAXA) tweeted that it had confirmed the mission’s twin rovers, called MINERVA-II 1A and 1B, had landed safely on the space rock Ryugu, and were moving on the surface.

The Hayabusa2 mothership deployed the small probes late last week as it dropped to just 55 metres above the surface, later pulling up to a higher orbit.


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Mission controllers at the Japan Aerospace Exploration Agency (JAXA) lost communication with the MINERVA rovers in the hours after deployment. The team said the silence was probably down to the landers being on the far side of the asteroid, as seen from the orbiter.

But the hexagonal rovers have now sent back their first, slightly blurry, colour images of their surface and made their first ‘hop’—their primary means of movement on the rock’s surface. The probes use rotating motors to make jumps, each lasting some 15 minutes owing to the body’s low gravity.

As well as taking images of the asteroid, the landers are designed to measure its temperature.

Before it leaves Ryugu next year, the Hayabusa2 mothership will release two more landers and, in late October, touch the surface itself to collect a sample to bring back to Earth.

Scientists hope that studying the 1-kilometre-wide-asteroid, which is made up of primitive material from the early Solar System, will help them to understand the origins and evolution of Earth and other planets.

This is not the first time scientists have explored an asteroid. In 2005, the mission’s predecessor, Hayabusa, landed on the surface of a smaller asteroid, called Itokawa, and collected a sample that it later returned to Earth. But this is the first time a lander has moved on an asteroid’s surface.

JAXA scientists reported their joy at the rovers’ success. “I cannot find words to express how happy I am,” said Yuichi Tsuda, project manager for the Hayabusa2 mission, in a statement.

This article is reproduced with permission and was first published on September 21, 2018.

Elizabeth Gibney is a senior physics reporter for Nature magazine.

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