Precise curation was necessary to discover that the Bennu asteroid sample contains building blocks of life on Earth.
Long before a NASA spacecraft carrying rocks it extracted from the surface of an asteroid millions of miles from Earth touched down in the Utah desert in September 2023, a team of scientists set about figuring out how to keep the rocks pristine for studying.
Central to that team was Kevin Righter, a University of Rochester earth and environmental sciences professor who was the curation lead for the NASA mission known as OSIRIS-REx.
"It was a lot of fun," Righter says of his role in the mission, which included helping to design a clean room at the Johnson Space Center in Houston, Texas, for the space rocks to be analyzed and identifying materials that could potentially contaminate them.
OSIRIS-REx, which stands for Origins, Spectral Interpretation, Resources Identification and Security-Regolith Explorer, has been a major win for NASA, and the space rocks it collected from Bennu, a carbon-rich asteroid hurtling through the solar system at 63,000 miles per hour, have been called a "precious gift from the cosmos" by NASA Johnson director Vanessa Wyche.
The analysis of the Bennu rocks, some results of which were recently published in the journals Nature and Nature Astronomy, revealed they contain chemical building blocks of life on Earth.
The findings support theories that asteroids like Bennu were among the deliverers of water and organic compounds to our planet. Scientists found minerals in the rocks, specifically salts, and the chemical components of proteins and nucleic acids found in DNA and RNA, some with characteristics that have not been found in meteorites that fall to Earth.
Philipp Heck, the senior director of research at the Field Museum of Natural History in Chicago and a member of the team at NASA that analyzed the Bennu sample, said the curation effort was vital to mission's success.
"The exciting discoveries made from the Bennu sample so far really highlight how essential it is to have such a carefully designed and executed curation process," Heck says. "It would not be possible otherwise."
Keeping space rocks pure is no simple task. Materials from outer space (meteorites) that pierce Earth's atmosphere get oxidized, hydrated, and heated to temperatures that can transform their organic compounds and some minerals.
Even air-tight canisters designed to hold precious space rocks, like the one on the OSIRIS-REx spacecraft, contain metals, alloys, and epoxies that could off-gas or have some volatility that could harm the sample.
The concerns do not stop there. Once the sample is safely delivered to Earth, where can it be studied without the threat of becoming tainted by earthly elements?
Key to the curation process was the use of so-called "witness plates"-flat plates made of aluminum and sapphire-that were exposed to all the same conditions as the sample from Bennu, creating a detailed record of potential contaminants.
If a compound found in the Bennu sample wasn't on the witness plate, scientists could confidently identify it as originating from Bennu. This is critical when dealing with organic compounds, where contamination can make it hard to distinguish what is truly extraterrestrial.
"The clues we're looking for are so minuscule and so easily destroyed or altered from exposure to Earth's environment," says Danny Glavin, a senior sample scientist at NASA who was the co-lead author of the Nature Astronomy paper. "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."
Righter, who was with NASA from 2002 until 2024, when he joined Rochester, was tapped for the curation role in the mission in 2011 based on his experience as curator of NASA's collection of Antarctic meteorites. Hundreds of meteorites hit Antarctica annually.
That collection is much larger than the specimen of rocks extracted from Bennu, which weighed about 120 grams, or roughly 4 ounces.
"It sounds like not much, but it's maybe the second largest amount of material the US has returned (since the Apollo moon missions) from another body," Righter says. "It's a lot of sample. To us, a 120 grams was, like, yes!"
He was the lead author of a paper published in Meteoritics & Planetary Science in April 2023 that detailed the work of his team in preparing for the sample, including building upon lessons learned from previous so-called "sample-return" missions, such as Apollo.
Righter led OSIRIS-REx curation efforts until March 2023, when NASA hired a full-time curator for the mission, and he joined the University of Rochester in July 2024.
But signs of work on the mission are close by. Frames on the wall of his office in Hutchison Hall showcase posters and images of the journey to Bennu and back. He says he was drawn to Rochester by the prospect of teaching and devoting more time to research. His future laboratory is currently being built next to his office.
"I've always wanted to teach, to be part of academia," Righter says. "That part of my life when I was in schooling was so rewarding and shaped my life in such a major way that I thought for many years it would be great to come back."
"I feel like I'm more engaged with research again," he says, "and ready to take off in several different directions."
