Most of the rocky bodies in the solar system have the scars of past impacts, but scientists can rarely see how those impacts occur in real time, and are about to have that opportunity.
The Japanese mission of Hayabusa2 To the asteroid, Ryugu arrived at his destination prepared to make it possible, through a maneuver called Small Transport Impact Operation. The operation is scheduled for tonight (April 4 in the US, the morning of April 5 at the Japan Aerospace Exploration Agency, or the JAXA headquarters).
You can watch a live broadcast from the control of the mission with English dubbing at Space.com, courtesy of JAXA, or directly through the agency's YouTube channel, starting at 8:30 p.m. EDT (April 5, 0030 GMT).
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The operation is designed to help scientists better understand the interior of the asteroid. Over the course of about 40 minutes, the Small Carry-on Impactor will separate from the main ship Hayabusa2, which will then be hidden from the other side of the asteroid to protect itself from flying debris. Along the way, Hayabusa2 will launch a camera that will observe the impact from a distance of approximately 1 km (1 mile) and send a couple of hours of photographs.
Then, it's show time. The impactor will approach the surface of the asteroid and then deploy explosives on board. The detonation will increase the speed of the impactor to 1.2 miles (2 km) per second in a fraction of a second, creating a new crater in Ryugu.
The deployed camera will photograph the entire event, recording how the debris moves away from the impact. These data will help, in particular, scientists to understand Ryugu's structure, including how much empty space is inside the rock
Once the dust settles, Hayabusa2 will come out from behind Ryugu. And if all goes well, scientists hope to take the main ship to the surface near the fresh crater to see the newly formed feature up close, and maybe even take a sample of the nearby rock.
The operation of Small Carry-on Impactor is one of the last tasks of Hayabusa2 in Ryugu: all that remains for the ship is to deploy a smaller rover, called MINERVA-II 2, which will take place later this summer. Then, it's time to return to Earth, samples on board.