Reviewed by Louis CastelFeb 3 2025
Scientists from NASA and other institutions reported the findings of the first in-depth analysis of the minerals and chemicals in the Bennu samples carried to Earth by OSIRIS-REx in 2023, in studies published in the journals Nature and Nature Astronomy.
In this video frame, Jason Dworkin holds up a vial that contains part of the sample from asteroid Bennu delivered to Earth by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) mission in 2023. Dworkin is the mission’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Image Credit: NASA/James Tralie
NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security–Regolith Explorer) spacecraft brought rock and dust samples from the asteroid Bennu to Earth. These samples have shown molecules that are essential to life on Earth, as well as a history of saltwater that may have acted as the “broth” for these compounds to interact and mix.
The results raise the possibility that life could have developed on other planets and moons, even though they do not provide evidence for life itself. They do, however, imply that the conditions required for life’s formation were common throughout the early solar system.
NASA’s OSIRIS-REx mission already is rewriting the textbook on what we understand about the beginnings of our solar system. Asteroids provide a time capsule into our home planet’s history, and Bennu’s samples are pivotal in our understanding of what ingredients in our solar system existed before life started on Earth.
Nicky Fox, Associate Administrator, Science Mission Directorate, NASA
Life on Earth uses nucleobases to store and transmit genetic instructions in more complex terrestrial biomolecules, like DNA and RNA, including how to arrange amino acids into proteins, and amino acids. All of them, as well as 14 of the 20 that life on Earth uses to make proteins, were among the most compelling discoveries made on Bennu.
In the Bennu samples, researchers also reported remarkably high ammonia abundances. Since it may react with formaldehyde, which was also found in the samples, to create complex compounds like amino acids under the correct circumstances, ammonia is significant to biology. Proteins, which power almost every human function, are created when amino acids join together to form lengthy chains.
These life-supporting elements discovered in the Bennu samples had previously been discovered in rocks from other planets. Finding them in a pure sample taken in space, however, lends credence to the theory that objects that originated far from the Sun may have served as a significant supply of the basic building blocks for life as we know it across the solar system.
The clues we’re looking for are so minuscule and so easily destroyed or altered from exposure to Earth’s environment. That’s why some of these new discoveries would not be possible without a sample-return mission, meticulous contamination-control measures, and careful curation and storage of this precious material from Bennu.
Danny Glavin, Senior Sample Scientist, Goddard Space Flight Center, NASA
Their colleagues, led by Sara Russell, a cosmic mineralogist at the Natural History Museum in London, and Tim McCoy, curator of meteorites at the Smithsonian's National Museum of Natural History in Washington, searched for hints about the environment in which these molecules would have formed while Glavin's team examined the Bennu samples for signs of life-related compounds. Scientists further detail evidence of an ancient environment that was ideal for igniting the chemistry of life in a report published in the journal Nature.
Scientists found signs of 11 minerals in the Bennu sample, ranging from calcite to halite and sylvite. These minerals are formed when water containing dissolved salts evaporates over an extended period of time, leaving the salts as solid crystals.
Similar brines have been found or suggested elsewhere in the solar system, such as at Saturn's moon Enceladus and the dwarf planet Ceres.
Although scientists have previously discovered many evaporites in meteorites that fall to Earth's surface, they have yet to find a full set that preserves an evaporation process that could have lasted thousands of years or more. Some minerals identified on Bennu, like trona, were discovered for the first time in extraterrestrial samples.
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.
Tim McCoy, Curator, Meteorites, Smithsonian’s National Museum of Natural History
Several questions remain after reviewing the Bennu sample's answers. Many amino acids can be produced in two mirror-image variants, similar to a pair of left and right hands. Life on Earth nearly exclusively produces left-handed individuals, but the Bennu samples include a balanced mix of both. This implies that on early Earth, amino acids may have started out in an equal combination. The reason life "turned left" rather than right remains a mystery.
“OSIRIS-REx has been a highly successful mission,” added Jason Dworkin, OSIRIS-REx project scientist at NASA Goddard and co-lead author on the Nature Astronomy study.
He added, “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’s the truly tantalizing question.”
OSIRIS-REx's overall mission management, systems engineering, safety, and mission assurance were all provided by NASA Goddard. Dante Lauretta of the University of Arizona in Tucson is the lead investigator. The university oversees the science team, as well as the mission's science observation planning and data processing.
Lockheed Martin Space in Littleton, Colorado, developed the spacecraft and managed its flight operations. NASA Goddard and KinetX Aerospace were in charge of navigating the OSIRIS-REx probe. Curation for OSIRIS-REx takes place at NASA's Johnson Space Center in Houston. This project's international partnerships include the Canadian Space Agency's OSIRIS-REx Laser Altimeter instrument and an asteroid sample science collaboration with JAXA's Hayabusa2 mission.
NASA's Marshall Space Flight Center in Huntsville, Alabama, oversees OSIRIS-REx, the third mission in the agency's New Frontiers Program, on behalf of the Science Mission Directorate in Washington.
Journal References:
Glavin, D. P., et. al. (2025) Abundant ammonia and nitrogen-rich soluble organic matter in samples from asteroid (101955) Bennu. Nature Astronomy. doi.org/10.1038/s41550-024-02472-9
McCoy, T. J., et. al. (2025) An evaporite sequence from ancient brine recorded in Bennu samples. Nature. doi.org/10.1038/s41586-024-08495-6