First OSIRIS-REx paper, co-authored by Rowan’s Connolly, suggests asteroid has properties necessary for life

First OSIRIS-REx paper, co-authored by Rowan’s Connolly, suggests asteroid has properties necessary for life

Above: top-down view of OSIRIS-REx material from near-Earth asteroid Bennu. Below right: A microscope image of a dark Bennu particle, about a millimeter long, with a crust of bright phosphate. Credit: NASA; Lauretta & Connolly et al. (2024) Meteoritics & Planetary Science.

The first academic article produced from a historic NASA asteroid sampling mission suggests material returned from space last September contains carbon, nitrogen and organic compounds, all of which are essential for life, as well as magnesium-sodium phosphate, which hints that the asteroid could have splintered off from a long-gone, primitive ocean world.

Co-lead authored by Dr. Harold Connolly Jr., mission sample scientist for the OSIRIS-REx project and chair of Rowan University’s Department of Geology in the School of Earth & Environment, some of the paper’s initial findings into the 4.3 oz return sample from the near-Earth asteroid Bennu surprised scientists evaluating the material.

“The Bennu samples are tantalizingly beautiful extraterrestrial rocks," Connolly said. “Each week, analysis by the OSIRIS-REx Sample Analysis Team provides new and sometimes surprising findings that are helping place important constraints on the origin and evolution of Earth-like planets.”

Published today in the journal Meteoritics & Planetary Science, “Surprising Phosphate Finding in NASA’s OSIRIS-REx Asteroid Sample” provides early analysis into the pristine Bennu sample and suggests it may reveal secrets from the formation of the solar system.

Of key importance, the OSIRIS-REx Sample Analysis Team has found that Bennu contains the original ingredients that formed the solar system. Dominated by clay minerals, particularly serpentine, the sample mirrors the type of rock found at mid-ocean ridges on Earth, where material from the mantle, the layer beneath Earth's crust, encounters water.

This interaction doesn't just result in clay formation; it also gives rise to a variety of minerals like carbonates, iron oxides, and iron sulfides. But the most unexpected discovery is the presence of water-soluble phosphates. These compounds are components of biochemistry for all known life on Earth.

While a similar phosphate was found in the asteroid Ryugu sample delivered by JAXA’s (Japan Aerospace Exploration Agency) Hayabusa2 mission in 2020, the magnesium-sodium phosphate detected in the Bennu sample stands out for the lack of inclusions in the mineral and the size of its grains, unprecedented in any meteorite sample.

The finding of magnesium-sodium phosphates in the Bennu sample raises questions about the geochemical processes that concentrated these elements and provides valuable clues about Bennu's historic conditions.

“The presence and state of phosphates, along with other elements and compounds on Bennu, suggest a watery past for the asteroid,” said Dr. Dante Lauretta, the other co-lead author of the paper and principal investigator for OSIRIS-REx at the University of Arizona, Tucson. "Bennu potentially could have once been part of a wetter world (but) this hypothesis requires further investigation."

From a Young Solar System

Despite its possible history of interaction with water, Bennu remains a chemically primitive asteroid, with elemental proportions closely resembling those of the Sun.

This composition offers a glimpse into the early days of the solar system, over 4.5 billion years ago, with rocks that have retained their original state, having neither melted nor resolidified since their inception, affirming their ancient origins, Lauretta said.

“These findings underscore the importance of collecting and studying material from asteroids like Bennu—especially low-density material that would typically burn up upon entering Earth's atmosphere,” said Lauretta. “This material holds the key to unraveling the intricate processes of solar system formation and the prebiotic chemistry that could have contributed to life emerging 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 are expected in the next few years from the OSIRIS-REx Sample Analysis Team.

Launched on Sept. 8, 2016, the OSIRIS-REx spacecraft traveled to near-Earth asteroid Bennu and collected a sample of rocks and dust from the surface. OSIRIS-REx, the first U.S. mission to collect a sample from an asteroid, delivered the sample to Earth on Sept. 24, 2023.

"OSIRIS-REx gave us exactly what we hoped: a large pristine asteroid sample rich in nitrogen and carbon from a formerly wet world," said Jason Dworkin, a co-author on the paper and the OSIRIS-REx project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.