spaceSpace and Physics

NASA Mission Is Leaving Asteroid Bennu And You Can Now See The Mark It Left


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockApr 16 2021, 17:28 UTC
Artist impression of OSIRIS-REx leaving Bennu in May.

Artist impression of OSIRIS-REx leaving Bennu in May. Image Credit: NASA/Goddard/University of Arizona

NASA’s OSIRIS-REx is only a few weeks away from the start of its journey back to Earth leaving asteroid Bennu behind for good. Well, not the whole asteroid. Last October 20, the NASA spacecraft touched briefly on the asteroid surface (Touch-And-Go maneuver or TAG) and collected a sample of soil and this will soon come to Earth.

During TAG the spacecraft sampling head sunk about half a meter (1.6 feet) into the soil releasing a charge of nitrogen gas to lift soil into the collection chamber. On April 7, OSIRIS-REx flew just 3.7 kilometers (2.3 miles) from Bennu, the closest it has been since TAG. And the team took this flyby to have a look at what the effect of TAG was.


"Bennu is rough and rocky, so if you look at it from a different angle or capture it at a time when the sun is not directly overhead, that dramatically changes what the surface looks like," Dathon Golish, a member of the OSIRIS-REx image processing working group, said in a statement. "These images were deliberately taken close to noon, with the Sun shining straight down when there's not as many shadows."

Bennu's surface before and after TAG. Image Credit: NASA/Goddard/University of Arizona

And OSIRIS-REx left a big old mark on Bennu. The surface was disturbed in three ways. By the spacecraft coming down, by the TAG event, and finally by the spacecraft’s retrorockets as it lifted away.

"These observations were not in the original mission plan, so we were excited to go back and document what we did," Golish said. "The team really pulled together for this one last hurrah."


Bennu is about 550 meters (1800 feet) across. OSIRIS-REx will leave the asteroid on May 10. The Sample Return Capsule is expected to delivered to Earth on September 24, 2023.

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