Scientists find life’s building blocks in asteroid Bennu’s particles. What’s next?

Four years after NASA’s OSIRIS-REx spacecraft collected a sample from the asteroid Bennu, researchers have unveiled the space rock’s unique composition, revealing a notable presence of magnesium phosphate.

This discovery was particularly unexpected, as the white particles found among the asteroid’s darker stones represent a type of mineral seldom encountered in space materials. Jessica Barnes, an assistant professor at the Lunar and Planetary Laboratory, who leads the analysis of the sample’s phosphate content, mentioned at the Lunar and Planetary Science Conference in Texas, that the uniqueness of this mineral on Earth made it initially suspected to be a contaminant due to its rarity or rapid degradation on our planet.

The sample’s detailed examination sheds light on the geological history of Bennu’s parent body, suggesting it underwent various geologic and hydrological events. Notably, the sample contained glycine, the simplest amino acid, along with water-related minerals like magnetite, sulfites, olivine, and carbonates. These findings indicate Bennu’s parent body experienced several episodes involving water before breaking apart to form Bennu.

Moreover, the analysis revealed a significant amount of water-altered compounds called phyllosilicates, alongside a diverse array of other hydrated and organic minerals.

The OSIRIS-REx mission successfully returned the sample to Earth in a secure capsule on September 24, 2023, and it was quickly transported to NASA’s Johnson Space Center in Houston for further study. A specialized team of scientists began examining the leaked material from the spacecraft’s sample collector, discovering a variety of textures and hydrated minerals indicative of space weathering typical for an ancient, airless celestial body.

Sara Russell, a planetary scientist at the Natural History Museum in London, commented on the exceptional quality of the sample, noting its distinctiveness from any meteorite in their collection, underscoring the sample’s scientific value and uniqueness.