Japanese mini-rovers send back their first images as they hop around an asteroid
An image from the Hayabusa 2 mission’s Rover-1A shows the surface of the asteroid Ryugu at left. The bright white region is due to sunlight. The image, captured at about 11:44 a.m. JST Sept. 22 (7:44 p.m. PT Sept. 21), is blurry because it was taken while the mini-rover was in the middle of a hop over the surface. (JAXA Photo)
Two mini-rovers have sent their first pictures back from the surface of the asteroid Ryugu, a day after they were dropped off by Japan’s Hayabusa 2 spacecraft.
The pictures are blurry because they were taken while the rovers were falling and hopping around the half-mile-wide asteroid, more than 180 million miles from Earth.
As fuzzy as they are, the photos represent a huge victory for the $150 million Hayabusa 2 mission, which was launched nearly four years ago to get an unprecedented look at the surface of an asteroid.
The Japan Aerospace Exploration Agency first tried to put a rover on the surface of an asteroid more than a decade ago, during a mission to a space rock called Itokawa. That part of the mission fizzled, however, when the MINERVA rover carrier missed the mark and sailed off into interplanetary space.
Hayabusa 2, in contrast, dropped its MINERVA-II-1 carrier right on target. The carrier deployed two 7-inch-wide, disk-shaped rovers that touched down on Ryugu’s rock-strewn terrain.
It took a while to get the pictures back to Earth because they had to be uploaded from the rovers to the mothership — and then relayed back to Earth for processing.
The first snapshot, taken during Rover-1A’s descent, shows Hayabusa 2 as a bright smudge in the black sky above and the surface of Ryugu as a bright smear below. Hayabusa’s solar panels, which account for most of the spacecraft’s 18-foot width, can be made out as fuzzy blue rectangles.
“Although I was disappointed with the blurred image that first came from the rover, it was good to be able to capture this shot as it was recorded by the rover, as the Hayabusa2 spacecraft is shown,” JAXA’s Tetsuo Yoshimitsu, a team leader for MINERVA-II-1, said today in a statement.
This image was captured by Rover-1A at about 1:08 p.m. JST Sept. 21 (9:08 p.m. PT Sept. 20), just after separation from the Hayabusa 2 spacecraft. Hayabusa 2 is at the top of the image, and Ryugu is at the bottom. The photo is blurry because it was taken while the rover was rotating. (JAXA Photo)
This image was captured by Rover-1B immediately after separation from the Hayabusa 2 spacecraft, at about 1:07 p.m. JST Sept. 21 (9:07 p.m. PT Sept. 20). The surface of Ryugu is at lower right. The colorful blur at upper left is due to the reflection of sunlight when the image was taken. (JAXA Photo)
An image taken by Rover-1B shows Ryugu’s rocks more clearly.
The rovers are built to spring up from the surface repeatedly and hop as far as 50 feet at a time. A follow-up image from Rover-1A showed the asteroid’s sun-illuminated surface from above during a hop. Yoshimitsu said that picture allowed him to “confirm the effectiveness of this movement mechanism on the small celestial body and see the result of many years of research.”
Hayabusa 2 project team spokesman Takashi Kubota seconded Yoshimitsu’s sentiment, saying that seeing the pictures taken in mid-hop “allowed me to relax as a dream of many years came true.”
“I felt awed by what we had achieved in Japan,” Kubota said. “This is just a real charm of deep space exploration.”
The pictures are reminiscent of the attention-grabbing views sent back from the surface of a comet by a European-built lander during the Rosetta mission.
When Makoto Yoshikawa looked at the rover pictures, he saw redemption. Yoshikawa served as project scientist for the original Hayabusa mission to Itokawa, and is now the project mission manager for Hayabusa 2’s rendezvous with Ryugu.
“I was so moved to see these small rovers successfully explore an asteroid surface, because we could not achieve this at the time of Hayabusa, 13 years ago,” he said.
The Hayabusa 2 mission team is continuing to acquire data for analysis, and further pictures are likely to be distributed first via the mission’s Twitter account.
A larger MASCOT rover, contributed by the German and French space agencies, is due to be dropped toward the surface next month. Next year, Hayabusa 2 will dispatch yet another mini-rover with its MINERVA-II-2 deployable carrier. The main spacecraft will also descend to the asteroid’s surface to collect samples for return to Earth in late 2020.