“The surface was soft and drained like a liquid.”
The original mission of NASA’s OSIRIS-REx spacecraft was to fly to the asteroid Bennu, where it meant landing briefly on the body’s presumably rocky surface, collecting a small sample, and returning home.
But while most of the mission miraculously went as planned, there was one big surprise along the way.
Amazingly, when OSIRIS-REx attempted to land on Bennu in 2020, it sank into the asteroid’s quicksand-like surface — likened to a “plastic ball pit” for children in a new NASA update — and released one blinding explosion of celestial matter.
Now, the mission’s researchers think they finally know why, as detailed in two new articles published this week.
“We expected the surface to be quite rigid, like landing on a pile of gravel: a bit of dust flies away and a few particles pop up,” Dante Lauretta, lead author of one of the studies and principal investigator on the OSIRIS-RE mission, told Space.com. “But when we brought the pictures back after the event, we were stunned.”
“There was clearly no resistance whatsoever,” she added. “The surface was soft and drained like a liquid.”
In fact, the result was so surprising that the researchers sent the ship back to Bennu six months later. Images collected on the second mission showed that OSIRIS-REx left behind a 65 foot wide impact crater called “Nightingale”.
According to a NASA statement, researchers believe the secret to Bennu’s unexpected fuzz lies in its bulk. The particles that make up the planet’s surface are both loosely packed and lightly bound, meaning that while it looks solid, it’s actually a lot of empty space.
As a result, NASA says stepping on the planet would apparently feel like “stepping into a pit full of plastic balls.” Yes, like the ones at your local Chuck E. Cheese.
The research is exciting, but to be honest it is also a bit nerve-wracking. Because Bennu is held together by so little force, an impact with Earth would likely result in the asteroid shattering in our Pale Blue Dot’s atmosphere, researchers say – a very different type of hazard compared to a collision with a hard celestial body.
CONTINUE READING: Dramatic sampling shows asteroid Bennu is not living up to scientists’ expectations [Space.org]
More on NASA’s advances: Here’s what you can expect from James Webb’s first images