OSIRIS-REx Shows Bennu Asteroid in Action
The asteroid Bennu is seen shedding material to space. Here’s a look at why its happening, and what it means for NASA’s OSIRIS-REx mission.
The OSIRIS-REx spacecraft recently reported strange activity around the asteroid Bennu — as the asteroid rotates, it is shedding fragments of rock out to space.
Located in the asteroid belt between Mars and Jupiter, Bennu is constantly bombarded by smaller debris. Some of these impacts drive material off the surface. Other pieces appear to be sheared off the body by uneven heating from the Sun as the asteroid rotates. Most of these pieces fall back onto the surface of the asteroid, but a small percentage of them break free of the weak gravitational field surrounding the body, entering interplanetary space.
The OSIRIS-REx space craft has studied Bennu in unprecedented detail since arriving at its target. The first evidence for debris being spread to space was seen when the spacecraft first reached the asteroid in January 2019.
The spacecraft takes periodic pictures of background stars, using their positions to navigate, in much the same way as ancient sailors. Examination of these images showed far more “stars” than researchers were expecting.
“I was looking at the star patterns in these images and thought, ‘huh, I don’t remember that…
