Asteroid NASA’s OSIRIS-REx mission landed on had a surface like a ‘pit of plastic balls’

Nearly two years ago, NASA made history when its OSIRIS-REx spacecraft briefly collected a sample of regolith from the asteroid’s surface. While the mission will not return to Earth, NASA shared new information about the celestial body. In a release released this week (via ) the agency revealed that OSIRIS-REx would have sunk in Bennu if the spacecraft had not fired its thrusters immediately after touching the asteroid’s surface.

“It turns out that the particles that make up Bennu’s exterior are so loosely packed and lightly bound together that if a person stepped on Bennu, they would feel very little resistance, like stepping into a pit full of plastic balls tread which are popular areas for children,” NASA said.

This is not what scientists thought they would find on Bennu. Observing the asteroid from Earth, one would expect its surface to be covered in smooth, sandy beach-like material. Bennu’s reaction to the OSIRIS-REx landing has also confused scientists. After a brief interaction with the asteroid, the spacecraft left a crater 8 meters wide. In lab tests, the pickup method “hardly made a divot.”

After analyzing the spacecraft’s data, they found that it encountered the same resistance that a human on Earth would feel when pressing the plunger of a French coffee pot. “When we fired our thrusters to leave the surface, we still crashed into the asteroid,” said Ron Ballouz, a scientist on the OSIRIS-REx team.

According to NASA, their findings on Bennu could help scientists better interpret long-distance observations of other asteroids. This, in turn, could help the agency design future asteroid missions. “I think we’re just beginning to understand these bodies because they behave in a very counterintuitive way,” said OSIRIS-REx team member Patrick Michel.