Update for 10 p.m. ET: Japan's Hayabusa2 has successfully collected its second sample from the asteroid Ryugu. Read our full story here!
A Japanese spacecraft is aiming to grab the first pristine sample of an asteroid to bring back to Earth tonight (July 10), and you can watch it approach the target now.
Hayabusa2 has been studying the space rock Ryugu for a year now, and has likely already sucked up a sample from its surface. In April, the spacecraft deployed a bullet to create an artificial crater, moving away long-weathered material and exposing fresh rock. The spacecraft spent weeks studying the new crater, and determined that the site is safe to approach for another sampling round. Now, it's approaching the asteroid in a process you can watch from the live images it's beaming back to Earth.
"We confirmed that it was extremely likely that we could safely secure a 2nd touchdown with the current capabilities of the Hayabusa2 team and spacecraft," Hitoshi Kuninaka, director general of the Japan Aerospace Exploration Agency (JAXA)'s Institute of Space and Astronautical Science, said in a statement. "We believe that success in this challenge will be a catalyst for advancing many future space science and exploration programs."
The sampling procedure is scheduled to begin around 9:15 p.m. EDT (0115 GMT or 10:15 a.m. local time at JAXA headquarters on July 11) and to last for about 40 minutes, although that timeline could change as the spacecraft moves through its operation. During the slow approach, Hayabusa2's navigation camera is sending back images of Ryugu in its sights. Those images will stop flowing sometime before touchdown, but JAXA will broadcast live from mission control, with English translation, beginning at 8:30 p.m. EDT (0030 GMT July 12).
Conducting a second touchdown maneuver represents a real risk to the spacecraft and its mission, since the operation is risky. Hayabusa2's first touchdown went smoothly, and Kuninaka confirmed that the agency believes the spacecraft is holding those samples. If something goes wrong, that success could disappear.
"When considering whether or not to perform the 2nd touchdown, it could be said that cancelling the 2nd touchdown and prioritising the return to Earth was the safest option for securing the early successes," Kuninaka said. "On the other hand, if the second touchdown is successful, subsurface material can be collected and scientific results further enhanced. However, this comes with the possibility of serious damage or a crisis that could threaten the return to Earth."
During the evaluation, the appeal of subsurface material won the team over from taking the more conservative approach. Hayabusa2 will now be targeting an area near the crater it created, looking to grab a sample of ejecta, or material thrown aside during the impact.
Scientists on the mission expect this material to be darker in color. That's because, buried below the surface until April, it has been protected from cosmic rays and the solar wind's charged particles passing through space. The second sampling effort will also help scientists to understand whether Ryugu is uniform or has patches of different materials.
Today's sampling is one of Hayabusa2's last major tasks before the spacecraft heads home. All that the spacecraft has left to do is to deploy one more rover, named MINERVA-II2. Around the end of the year, Hayabusa2 will bid farewell to Ryugu for good and ferry its precious cargo back to Earth.
- Watch Japan's Hayabusa2 Grab a Piece of an Asteroid in This Incredible Video!
- Shadow Selfie! Japanese Asteroid Probe Snaps Amazing Post-Landing Pic
- Japan's Hopping Rovers Capture Amazing Views of Asteroid Ryugu (Video)
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Meghan is a senior writer at Space.com and has more than five years' experience as a science journalist based in New York City. She joined Space.com in July 2018, with previous writing published in outlets including Newsweek and Audubon. Meghan earned an MA in science journalism from New York University and a BA in classics from Georgetown University, and in her free time she enjoys reading and visiting museums. Follow her on Twitter at @meghanbartels.