by Scientists are now examining bits and pieces snagged, bagged and tagged from asteroid Bennu, the cosmic mother lode that delivers NASA’s Origin, Spectral Imaging, Resource Identification and Security – Regolith Explorer mission.
Called OSIRIS-REx in the star-speak acronym, the seven-year journey brought the goods home via a sample return trajectory that came to a complete stop on September 24, 2023, parachuting into a remote Department of Defense field in Utah. . Test and Training Range. These distant specimens are believed to contain what was left of the formation of the solar system 4.5 billion years ago.
Space.com caught up with two leading scientists who are in the process of extracting these dark asteroid particles, as they unravel how these materials exported from Bennu came to be. But also what insights they have into the origins of the world within our solar system, including Earth.
Related: NASA’s 1st asteroid sample rich in carbon and water, discovered by the OSIRIS-REx team
Pristine reservoir
The location is the University of Arizona’s Kuiper-Arizona Laboratory for Astromaterials Analysis. Researchers are then using tools to tell them what OSIRIS-REx is collecting, right down to the atomic scale.
To begin with, University of Arizona scientists obtained 200 milligrams – about seven thousand ounces – of the Bennu asteroid sample for analysis.
“We have over 1,000 particles that are larger than half a millimeter, 28 particles that are larger than a centimeter, and the largest particle is 3.5 centimeters,” said Dante Lauretta of the University of Arizona, the principal investigator for OSIRIS-REx. “So, a great collection full of really big stones.”
The Bennu samples contain a lot of water locked in minerals such as clays and are also rich in carbon, nitrogen, sulfur and phosphorus. The OSIRIS-REx samples represent the largest pristine reservoir of such material in the world.
“We’re going to be busy for a long time,” Lauretta told Space.com. “This is a great example for us,” he said, with specimens of Bennu now also being studied around the globe.
Distinctive and different
The 55th Lunar and Planetary Science Conference to be held in The Woodlands, Texas next month reveals what’s to come. Over 70 abstracts of scientific output have been submitted to that prestigious meeting, Lauretta said. “Starting in March that everything is going to be released to the world. So the team is working furiously,” he said.
One early result is that the asteroid material being probed “looks distinct and isotopically different than anything else in our meteorite collection, which is exciting,” Lauretta said. “There’s a whole area of content that we don’t get access to if we’re just relying on dragnets,” Lauretta added.
Most meteorites are pieces of asteroids that suffer a fiery fall through the Earth’s atmosphere and are recovered. But the space rock from which they came is not easily pinpointed.
phosphate crust
The OSIRIS-REx samples have a phosphate crust never seen before in meteorites, Lauretta said. These high phosphate concentrations have been detected in the world’s extraterrestrial oceans, he said.
For example, Saturn’s moon Enceladus, the main building block of life, contains phosphates at much higher levels than Earth’s oceans.
“Asteroid Bennu could be a fragment of an ancient ocean world. That’s still very speculative. But it’s the best lead I have now to explain the origin of that material,” said Lauretta.
Connect the dots
Unraveling Bennu’s asteroid history is a surreal undertaking, said Thomas Zega, a professor in the university’s Lunar and Planetarium Laboratory and science director at the school’s Kuiper-Arizona Laboratory for Astromaterials Analysis.
Zega points out the years that the OSIRIS-REx mission has reserved, from an improved proposal to the asteroid samples being actually studied in the laboratory.
“Honestly, there’s rarely a day that goes by when I don’t feel lucky to do this for a living,” Zega told Space.com. “I pinch myself. It’s a blessing.”
By any definition the OSIRIS-REx mission has been a resounding success, Zega added, “and now being able to use some of the most sophisticated analytical tools on the planet to measure the samples is really impressive. “
Zega said missions like OSIRIS-REx, in addition to teaching scientists about the origin of Bennu, “really help us connect the dots between the other meteorites in our terrestrial collections,” he said, “and possibly the asteroids from which they come in the asteroid belt between Mars and Jupiter.”
Quick-search
Zega was a member of the “quick look” team that participated in the opening of the OSIRIS-REx sample return capsule after it was delivered to NASA’s Johnson Space Center in Houston, Texas.
What the conservation team experts found was a coating of fine-grained dust from the sampling maneuver at Bennu on the returned avionics deck and on the outside of the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) — the air-filter contraption on. the end of OSIRIS-REx’s robotic arm that overcame most of the Bennu fragments.
One aspect of Zega’s surreal encounter with Bennu is to leave Texas and fly back to Arizona with a small fraction of a sample from the pre-arranged asteroid.
After all, Zega’s express courier duties are due to the University of Arizona being the home base for 20 years of work to transition OSIRIS-REx from propulsion to ballistic entry of asteroid material.
The cover of darkness
“There was no way it was going into checked baggage! It went into my backpack that I carried on the plane. It was a small item, sealed in a bag that was itself sealed in vial that was filled with nitrogen. So it was all protected,” Zega recalled.
Landing in Tucson at night, the first thing Zega did was to push the sample into a dry nitrogen box in the university’s laboratory for protection and preservation.
“And then I went home, had dinner, and went to sleep,” said Zega.
Zega said he was joking that the whole thing was under the cover of darkness. “No one was the wiser that someone had just brought the first sample from NASA’s first asteroid sample return to Tucson,” he said.
Stay tuned
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Last month, on January 10, NASA curators opened the OSIRIS-REx TAGSAM head that is completely filled with bits of Bennu. That last step was slow in coming due to a few troublesome fasteners that prevented a visual inspection of the entire collectible asteroid shipment.
Now on tap a catalog of all the Bennu samples is being released later this year, giving scientists and institutions around the world the ability to submit requests to scrutinize the spacecraft’s Bennu clutches.
Meanwhile, Lauretta and Zega, along with their colleagues, are appraising Bennu’s specimens.
Teams of university students and faculty are using a wide range of capabilities, from optical and electron microscopes to newly acquired instrumentation.
The powerful nanoSIMS tool is up and running and offering a look at isotopes (different variations of atoms) to help interpret how each individual component in the Bennu sample came to be.
“We have a lot of cool things happening in the next few months,” Lauretta said. “So stay tuned.”
