Elizabeth Howell, Space.com Contributor reports: A Japanese sample-return spacecraft just gave its destination asteroid a special close-up. As Hayabusa2 swept to only 1 kilometer (0.6 miles) above the surface of 162173 Ryugu, it spotted boulders, dust and surface features only a few meters or feet across. It’s by far the best view of Ryugu since the spacecraft arrived there about six weeks ago.
Several images from Ryugu show the surface of this space rock, which occasionally crosses the orbit of Earth, as it dipped down toward the asteroid. (Scientists classify Ryugu as a potentially hazardous asteroid, but there is no imminent threat to our planet.) In general, studying the surface of small worlds helps scientists better understand solar system history. Engineers can also use the composition information so that, if Earth is threatened by a large asteroid, they can better pick a deflection or destruction method.
This time around, though, the pictures were not the main reason Hayabusa2 swept so low. Instead, Japanese controllers were interested in better understanding the gravity of Ryugu. To do so, they put the spacecraft into a temporary free fall.
“By monitoring the exact movement of the Hayabusa2, we can see how strong the gravitational attraction is from Ryugu,” officials with the Japan Aerospace Exploration Agency (JAXA) said in a statement today (Aug. 7) … (read more)