OSIRIS-REx is slowly getting ready to go home, where he will set off on May 10, and now he is basically just waiting for this date. Earlier, however, he had once again flown around the asteroid Bennu to look at the Nightingale crater, the place where he flew briefly last year and collected material by suddenly releasing compressed nitrogen. At the same time, it was able to significantly noticeably damage the surface of the asteroid, which is a consequence of three things: landing, collection, and departure.
When looking at photos from the landing site, it is necessary to realize, above all, how big the structures are on it. In the right part, we can identify a large piece of rock that previously posed a potential threat to the probe during its maneuvers. From our point of view, the height is about 10 meters, which means that the boulder, which was thrown by the probe to a distance of more than 10 meters from its original position, has a diameter of at least a meter. However, on an asteroid just over half a kilometer in diameter, there is, of course, a slightly different gravity than we are used to, and the average density of the material that makes up Bennu is only slightly higher than that of water. Even so, it will weigh around one ton, which is not easy to move.
OSIRIS-REx was thus able to significantly disturb the space directly below it, which can be found in the middle of the crater, with strong nitrogen pressure, while the collection basket sank almost 50 cm below the surface. However, the largest clearing was then created by nozzles, with the help of which the probe quickly moved away after collection.
At the same time, NASA had to carefully plan the spacecraft to fly over the landing site so that OSIRIS-REx would be in the right position when the Nightingale was lit, if possible, as it was when taking older photographs. The shadows are slightly different, but the images are well comparable and show that the probe left a darker surface, revealing a weak top layer of rock.
The probe is now only home for more than two years, and according to the plan, the container with the samples is to reach Utah on September 24, 2023.