'Unanticipated discovery': NASA scientists detail findings from asteroid that landed in Utah
by Collin Leonard, KSL.com · KSL.comEstimated read time: 4-5 minutes
SALT LAKE CITY — After examining just 0.06% of a 120-gram material sample from the surface of asteroid Bennu — which returned to Earth in Utah's west desert in September 2023 — a group of scientists has already found a few surprises, publishing a flurry of papers Wednesday.
"I'm sure, like me, you all watched in wonder as we saw that beautiful capsule come down under that amazing red and white parachute in the Utah desert," NASA administrator Nicky Fox said in a press call.
OSIRIS-REx was the first U.S. mission to collect a sample from an asteroid, the nation's first sample return mission since the Apollo era more than 50 years ago. The spacecraft held the record for the smallest orbit around a planetary body, at only 1,227 feet above the surface, Fox said, around the height of the Empire State Building.
For the past year, scientists have been studying it, the largest asteroid sample ever collected from beyond the moon.
"These samples provide a really unique opportunity to explore the prebiotic organic chemistry that occurred in the solar system prior to the emergence of life," Danny Glavin, NASA's senior scientist for sample return, said. His team made what it called "Bennu tea" for their experiments.
"We actually took samples, we boiled them in water and acids to extract the organic compounds to make this, this liquid, this tea, which we then analyzed using several different mass spectrometry techniques to identify the organic molecules," he said.
What did they find? "A really complex soup of organic molecules," according to Galvin, including over 10,000 nitrogen-bearing organic molecules, along with "the building blocks of life."
Scientists found 14 of the 20 amino acids used to build proteins and all five nucleobases, the genetic components of DNA and RNA.
"These molecules have been found before in meteorites," Glavin said. "But what's so significant about the Bennu findings is that those samples are pristine. They were protected from the atmospheric entry heating by the sample return capsule. They were protected from contamination, from terrestrial biology, whereas all meteorites are exposed to some level of contamination."
He added, "The bottom line is, we have a higher confidence that the organic material we're seeing in these samples are extraterrestrial and not contamination. We can trust these results."
Surprises in the dust
"I've been waiting for 20 years to tell you about this work," said Tim McCoy, curator of meteorites at the Smithsonian Natural History Museum.
He said Bennu is "a rubble-pile asteroid, relatively small, about 500 meters across, but it came from an ancestral asteroid of rock and ice that broke apart a billion or two years ago — early in the history of the solar system."
The ice melted with heat from the radioactive decay of elements, McCoy said, and the resulting water reacted with rock to produce minerals that scientists have observed in meteorites and from the 2-year orbit around Bennu.
"There was a surprise," according to McCoy, who said, "That surprise was that we've had a whole set of minerals that are really rich in sodium — carbonates and phosphates and sulfates, chlorides and fluorides."
Four and a half billion years ago, the ancestral asteroid Bennu broke away from had "pockets or veins of fluid, perhaps only a few feet wide under the surface," McCoy said. "Within those cracks evaporation occurred, water was lost to the surface, and these minerals were left behind."
A paper released Wednesday by Japanese researcher Yasuhito Sekine calls these "extremely delicate salts" from an "ancient brine" that have not been observed in extraterrestrial samples but may help scientists establish "the history of water in the early solar system."
Sarah Russell, cosmic mineralogist at the Natural History Museum in London, said, "It was fantastic for us because it was an entirely unanticipated discovery. We weren't just confirming what we thought we already knew about the asteroid, but we were finding out something completely novel."
This data tells a story, where water, organic material and "bio-essential elements" could have traveled on asteroids like Bennu in the early solar system, colliding with Earth and other planets, seeding them with "all the ingredients they needed to kick start life," according to Russell.
No evidence of life
To be clear, there was no evidence found of life on Bennu, despite many of the building blocks.
"We have looked through the Bennu sample at a very fine level, a sort of micron level, a millionth of a meter and less, and we don't see any cellular structures that you might expect if there were fossils in there. We don't see either structural fossils or chemical fossils either," Russell said. "So we have no evidence to suggest that there was life on Bennu."
More than 75% of the sample remains unexplored, OSIRIS-REx project scientist Jason Dworkin says. Pieces are archived at the NASA Johnson Space Center, a lab in Japan and soon, at a Canadian space agency facility. Scientists from across the world have the opportunities to request samples for study.
Another piece of Bennu will be stored at negative 110 degrees Fahrenheit for 50 years, "so that perhaps scientists not yet born using methods not yet invented, can make discoveries we haven't imagined," Dwarkin said. It's "the gift that keeps on giving."
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Collin Leonard
Collin Leonard is a reporter for KSL.com. He covers federal and state courts, northern Utah communities and military news. Collin is a graduate of Duke University.