In 2020, NASA’s OSIRIS-REx spacecraft would go to Bennu, an asteroid roughly 200 million miles from Earth, land briefly, gather a small sample, and return home. However, its mission was thwarted not by a Space Force scenario or a black hole anomaly, but by Bennu’s surface, which is more akin to a “plastic ball pit” than a solid surface, according to NASA in a new report.
“The spacecraft would have sunk into Bennu if it hadn’t instantly fired its engines to back away after grabbing dust and rock from the asteroid’s surface,” NASA reported. “It turns out that the particles making up Bennu’s exterior are so loosely packed and lightly bound to each other that if a person were to step onto Bennu they would feel very little resistance, as if stepping into a pit of plastic balls that are popular play areas for kids.”
When the OSIRIS-REx sunk below Bennu’s surface two years ago, it attempted to land. According to two new articles published this week by the mission’s researchers, they now know why.
“We expected the surface to be very stiff, kind of like landing on a gravel pile: a little bit of dust blowing away and a few particles rising up,” Dante Lauretta, a planetary scientist at the University of Arizona and the OSIRIS-REx mission’s main investigator, told Space.com. “However, we were stunned while we were bringing back the photographs after the event.”
We saw a giant wall of debris flying away from the sample side. For spacecraft operators, it was really frightening. We expected the surface to be very stiff, kind of like landing on a gravel pile: a little bit of dust blowing away and a few particles rising up.
Dante Lauretta
She said the surface was “soft and flowed away like a fluid.” I have never wanted to jump into anything more in my entire life, but that probably isn’t a great idea considering that it is in space and I am not an astronaut.
We also don’t know a ton about these kinds of asteroids. Patrick Michel, an OSIRIS-REx scientist and director of research at the Centre National de la Recherche Scientifique at Côte d’Azur Observatory in Nice, France told NASA that “we’re still at the beginning of understanding what these bodies are, because they behave in very counterintuitive ways.” Moreover, looking back at images from the 2020 crash that left a 65-foot-wide impact crater was pretty wild, according to Lauretta.
“We saw a giant wall of debris flying away from the sample side,” Lauretta said, dashing my hopes of sinking into an entire asteroid-size Chuck E. Cheese attraction. “For spacecraft operators, it was really frightening.”
Despite its delicate and fluffy appearance, Space.com describes Bennu as “one of the most deadly asteroids currently known,” because a collision with Earth would inflict “continent-wide damage on our planet.” Fortunately, NASA believes the impact is extremely unlikely – 1 in 2,700 between the years 2175 and 2199, to be exact.
The results were so unexpected that the researchers returned the ship to Bennu six months later. The second mission’s imaging revealed that OSIRIS-REx had left a 65-foot-wide impact crater called “Nightingale” in its aftermath.
According to a NASA statement, the experts believe Bennu’s unexpected fluff is hidden in its mass. The particles that make up the asteroid’s surface are both loosely packed and lightly bonded, which means that while it appears solid, there is a lot of empty space underneath. As a result, NASA claims that getting onto the asteroid is like “stepping into a pit of plastic balls.” Yes, like the ones at Chuck E. Cheese’s.
The research is intriguing, but it’s also a little nerve-racking. According to the researchers, because Bennu is held together by so little force, an impact with Earth would likely cause the asteroid to break within our Pale Blue Dot’s atmosphere – a totally different type of threat than a collision with a hard celestial body.
