Japan’s Hayabusa-2 spacecraft has successfully landed on the asteroid Ryugu for a second time, firing a projectile into the surface in the process and hopefully kicking up material into a collector that will return to Earth.
At 10.06am local time in Japan today, Thursday July 11 (9.06pm Eastern time yesterday, Wednesday July 10), the spacecraft briefly touched the surface of the asteroid using a meter-long sampling arm. Images then showed material swirling up around the arm, indicating the projectile had been fired into the surface.
In a press conference following the landing at mission control in Sagamihara, Takashi Kubota – the research director for the mission – said the landing had been “more than perfect”. Project manager Yuichi Tsuda rated the landing “1,000 points out of 100,” noted the Japan Times.
The entire landing was autonomous, with the mission operations team only learning that the landing had been a success after the data from the spacecraft made the trek of 290 million kilometers back to Earth. It had taken about a day for the spacecraft to gradually lower itself to the asteroid, but the landing itself lasted just minutes after a brief planned hold at an altitude of 30 meters above the surface.
“From the data sent from Hayabusa2, it has been confirmed that the touchdown sequence, including the discharge of a projectile for sampling, was completed successfully,” the Japanese Space Agency (JAXA) said in a brief statement. “Hayabusa2 is functioning normally, and thus the second touchdown ended with success.”
The spacecraft is now returning to its safe home position about 20 kilometers above the asteroid, which it is expected to reach overnight tonight. The spacecraft will continue to send data from the landing back to Earth, including more images that could give a clear indication of how much material was kicked up into the spacecraft’s collector.
Hayabusa-2 lacks any means to know if the collection of material from the surface was a success. It has three chambers to collect material, although only two have been used on the mission. One, chamber B, is thought to have material from the first landing in February 2019. Chamber C, meanwhile, was used for this landing.
However, it will not be until the spacecraft returns to Earth that scientists learn for sure if the spacecraft successfully collected material. If it did, it’s hoped that up to 0.1 grams may be on board, a small amount but enough to work out some key information about the asteroid.
Hayabusa-2’s first landing site was on the surface of the asteroid, collecting material that had been blasted by the Sun’s radiation and cosmic rays since the dawn of the Solar System 4.5 billion years ago. But on this landing, JAXA had previously fired an impactor into the surface of the asteroid in April 2019, forming a small crater.
The spacecraft touched down in a region just above the crater, where it’s believed pristine material that had previously been hidden underground had been spewed onto the surface. If Hayabusa-2 successfully picked up material from this region, it could give us a fascinating look at untouched material from before even Earth was formed, which could, in turn, teach us about the origins of water – and even life – on Earth.
“We’ve collected a part of the Solar System’s history,” JAXA project manager Yuichi Tsuda said at the press conference. “We have never gathered subsurface material from a celestial body further away than the Moon.”
Hayabusa-2 will remain at the asteroid Ryugu until late 2019. Then it will leave and make its journey back to Earth, arriving at the end of 2020 and deploying a capsule containing the two samples from the surface. These will be collected from the landing site in Australia to be studied by eager scientists around the world.
Today’s landing is Japan’s second asteroid landing mission overall, after Hayabusa-2′s predecessor – Hayabusa-1 – touched down on the surface of asteroid Itokawa in 2005, returning a small sample 0.001 grams in size to Earth in 2010.
