NASA Discovers Life’s Building Blocks in Bennu Sample Analysis

NASA’s OSIRIS-REx mission has confirmed the presence of organic molecules and water-related minerals in rock and dust samples from asteroid Bennu. The findings, detailed in research published in Nature and Nature Astronomy, suggest that key ingredients for life existed in the early solar system.

Initial analysis revealed 14 amino acids essential for protein formation, along with all five nucleobases necessary for DNA and RNA. These discoveries indicate that celestial bodies could have transported fundamental components for life to Earth.

"The clues we are looking for are so minuscule and so easily destroyed or altered by exposure to Earth’s environment. That is why some of these new discoveries would not be possible without a sample-return mission, meticulous contamination-control measures, and careful curation of this material from Bennu," said Danny Glavin, senior sample scientist at NASA's Goddard Space Flight Center.

Scientists also identified high concentrations of ammonia and formaldehyde in the samples. Under the right conditions,these compounds can combine to form more complex molecules, including amino acids.

Researchers detected 11 minerals in the Bennu samples, including calcite, halite, and sylvite, which form when saline water evaporates over long periods. The discovery of trona in an extraterrestrial sample is unprecedented.

"These papers really go hand in hand in trying to explain how life’s ingredients actually came together to make what we see on this aqueously altered asteroid," said Tim McCoy, curator of meteorites, Smithsonian’s National Museum of Natural History.

Similar brines have been observed on celestial bodies like Ceres and Enceladus, supporting the idea that water-rich environments were widespread in the early solar system.

Despite these findings, questions remain. Amino acids found in the Bennu samples exist in both left- and right-handed configurations, whereas life on Earth predominantly utilizes left-handed amino acids. This suggests that prebiotic chemistry may have started with an even distribution before life selected a specific orientation.

"OSIRIS-REx has been a highly successful mission. Data from OSIRIS-REx adds major brushstrokes to a picture of a solar system teeming with the potential for life. Why we, so far, only see life on Earth and not elsewhere, that is the truly tantalizing question," said Jason Dworkin, project scientist, NASA Goddard.

NASA’s OSIRIS-REx spacecraft delivered the Bennu samples to Earth in 2023. The mission, part of NASA’s New Frontiers Program, is managed by the Marshall Space Flight Center. The Johnson Space Center oversees curation, while international collaborations include Canada’s OSIRIS-REx Laser Altimeter and Japan’s Hayabusa2 mission.