Japan’s Hayabusa 2 probe began the climactic phase of its mission overnight by sending out its first two rovers as it hovered less than 200 feet over an half-mile-wide asteroid, more than 180 million miles from Earth.
During the drop-off, the 18-foot-wide spacecraft even took a picture of its own shadow, spread out on the asteroid Ryugu’s rocky surface like a black-and-white copy of the Canadian flag.
The release of Hayabusa 2’s MINERVA-II-1 rovers occurred at 9:06 p.m. PT Thursday, mission controllers at the Japan Aerospace Exploration Agency reported in a tweet. Hayabusa 2 dipped as low as 55 meters (180 feet) for the release, then retreated back from the asteroid.
Hayabusa 2 was launched nearly four years ago and made its rendezvous with Ryugu in June. The goal of the $260 million mission is to study the asteroid in depth, from space and from the surface, and bring samples back to Earth in late 2020. Such samples could shed additional light on the solar system’s formation and life’s chemical building blocks.
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This mission follows up on the first Hayabusa odyssey, which touched down on the asteroid Itokawa in 2005 and returned a smattering of samples in 2010.
Hayabusa 1 had a similar lander experiment, known as MINERVA (which stands for “Micro Nano Experimental Robot Vehicle for Asteroid”), but the drum-sized rover container missed making its landing and sailed off into interplanetary space instead.
If MINERVA-II-1’s container follows its proper course, two 7-inch-wide rovers will touch down on Ryugu’s surface, hop around and take pictures. Stereo images from Rover-1A and Rover-1B would be sent up to the Hayabusa 2 mothership, and then relayed back to Earth.
Ryugu’s gravity is so weak that it could take up to 15 minutes for a rover to make a slow, single hop from one spot to another spot up to 50 feet (15 meters) away.
MINERVA-II-1 is just the first surface sortie for Hayabusa 2. A larger, instrument-laden lander, provided by the German and French space agencies and known as MASCOT (“Mobile Asteroid Surface Scout”), will be dropped off next month. Another rover package, MINERVA-II-2, is due to be deployed next year.
The main spacecraft itself is also scheduled to descend to the surface in 2019 and collect samples for the return trip.
This is a big year for studying small solar system bodies: NASA’s OSIRIS-REx spacecraft is expected to rendezvous with the asteroid Bennu in December and begin an observational campaign aimed at collecting its own set of surface samples for return to Earth in 2023.
Meanwhile, the New Horizons spacecraft is closing in on a New https://www.asteroidmission.org/Year’s flyby past an icy celestial body nicknamed Ultima Thule, and NASA is winding up its Dawn mission at Ceres, the biggest known asteroid and the smallest known dwarf planet.