Record Amount of Rock Samples Collected to Discover an Asteroid’s Origins

Over 120 grams of pebbles and small rocks have been collected from the asteroid Bennu’s surface, and astrophysicists hope to further their understanding of planetary formation, the origin of water on Earth, and even the building blocks of life itself.

“We are doing a lot of work in Houston, in the curation lab, to understand the nature of that material,” explains Professor Dante Lauretta, the principal investigator for OSIRIS-REX. “Those are the rarer parts of the collection and are scientifically really valuable because you get the whole rock texture at a larger scale. And that’s going to be important for the processes that we want to study.”

NASA‘s OSIRIS-REX hauled a total of 121.6 grams – double the mission goal – from Bennu. In comparison, only grains have been collected from two space rocks, Itokawa and Ryugu. It is the largest haul of asteroid material in the history of humanity. The data obtained from a single gram from Bennu was distributed to research centres in the United States and internationally, generating 58 presentations to be unveiled at the upcoming Lunar and Planetary Science Conference. Scientists follow three lines of evidence to prove that Bennu comes from an ocean world – a much larger body with liquid water – possibly under an icy or rocky exterior like the icy moons of Jupiter or Saturn. The first is the evidence of serpentinite, which forms when hot igneous or metamorphic rocks meet water. The second is the bulk composition of elements soluble in water, like sodium, potassium, uranium, thorium, and barium. The third one is the presence of a phosphate crust on some samples, a coating left behind as water evaporates. Furthermore, Bennu could open a window into the early times of the Solar System and planetary formation.