Early analysis of the asteroid Bennu sample, returned by NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-Rex) mission, unveils unexpected discoveries. Among the most intriguing findings is the presence of magnesium-sodium phosphate, a mineral not previously detected by the spacecraft’s remote sensing instruments during its time at Bennu.
This phosphate discovery, reported in a recent publication in Meteoritics & Planetary Science, offers new insights into Bennu’s composition and potential history. The mineral’s purity and grain size are unprecedented in meteorite samples, distinguishing it from similar phosphates found in other asteroid samples. https://onlinelibrary.wiley.com/doi/10.1111/maps.14227
The presence of this water-soluble phosphate, along with other elements and compounds, suggests a watery past for Bennu. This finding hints at the possibility that Bennu may have once been part of a larger, wetter celestial body. Beyond the phosphate discovery, the Bennu sample is rich in carbon, nitrogen, and organic compounds – essential components for life as we know it.
These findings underscore the importance of sample return missions in space exploration. By bringing pristine asteroid material back to Earth, scientists can conduct detailed analyses that are impossible with remote sensing alone, potentially unlocking secrets about the formation of our solar system and the origins of life on Earth.
Dozens more labs in the United States and around the world will receive portions of the Bennu sample from NASA’s Johnson Space Center in Houston in the coming months, and many more scientific papers describing analyses of the Bennu sample are expected in the next few years from the OSIRIS-REx Sample Analysis Team.
Picture Source: From Lauretta & Connolly et al. (2024) – Phosphate in a mottled particle (OREX‐803009‐101). (a) Visible light microscopy image of a dark particle with an outer crust of high‐reflectance material. (b–d) SEM images showing progressively zoomed view of a fragment of the particle that split off along a high‐reflectance vein, revealing material similar to the outer crust, with a blocky friable texture and consisting of Na, Mg, and P.