Bennu asteroid sample found to contain carbon and water

Initial studies of a sample of the 4.5-billion-year-old asteroid Bennu, collected in space and brought to Earth by NASA last month, show evidence of high carbon content and water, which together indicate that the building blocks of life on Earth may be found in the rock.

This finding was announced from NASA’s Johnson Space Center in Houston, following a preliminary assessment by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer) science team. The announcement was made less than 24 hours before the scheduled launch of NASA’s Psyche spacecraft from the Kennedy Space Center in Florida, with its sights set on a mysterious, one-of-a-kind asteroid which it is expected to reach in 2029.

The goal of the OSIRIS-REx sample collection was 60 grams of asteroid material. Curation experts at NASA Johnson, working in new cleanrooms built especially for the mission, have spent 10 days so far carefully disassembling the sample return hardware to obtain a glimpse at the bulk sample within. When the science canister lid was first opened, scientists discovered bonus asteroid material covering the outside of the collector head, canister lid and base. There was so much extra material that it slowed down the process of collecting and containing the primary sample.

Within the first two weeks, scientists performed ‘quick-look’ analyses of that initial material, collecting images from a scanning electron microscope, infrared measurements, X-ray diffraction and chemical element analysis. X-ray computed tomography was also used to produce a 3D computer model of one of the particles, highlighting its diverse interior. This early glimpse provided the evidence of abundant carbon and water in the sample.

“The OSIRIS-REx sample is the biggest carbon-rich asteroid sample ever delivered to Earth and will help scientists investigate the origins of life on our own planet for generations to come,” said NASA Administrator Bill Nelson.

Although more work is needed to understand the nature of the carbon compounds found, the initial discovery bodes well for future analyses of the asteroid sample. The secrets held within the rocks and dust from the asteroid will be studied for decades to come, offering insights into how our solar system was formed, how the precursor materials to life may have been seeded on Earth, and what precautions need to be taken to avoid asteroid collisions with our home planet.

“As we peer into the ancient secrets preserved within the dust and rocks of asteroid Bennu, we are unlocking a time capsule that offers us profound insights into the origins of our solar system,” said Dante Lauretta, OSIRIS-REx principal investigator. “The bounty of carbon-rich material and the abundant presence of water-bearing clay minerals are just the tip of the cosmic iceberg.

“These discoveries, made possible through years of dedicated collaboration and cutting-edge science, propel us on a journey to understand not only our celestial neighbourhood but also the potential for life’s beginnings.”

For the next two years, the mission’s science team will continue characterising the samples and conduct the analysis needed to meet the mission’s science goals. NASA will preserve at least 70% of the sample at Johnson for further research by scientists worldwide, including future generations.

“NASA missions like OSIRIS-REx will improve our understanding of asteroids that could threaten Earth while giving us a glimpse into what lies beyond,” Nelson said. “The sample has made it back to Earth, but there is still so much science to come — science like we’ve never seen before.”

Image caption: A view of the outside of the OSIRIS-REx sample collector. Sample material from asteroid Bennu can be seen on the middle right. Image credit: NASA/Erika Blumenfeld & Joseph Aebersold.