Scientists are currently examining bits and pieces fitted, packaged and labeled from asteroid Bennu, the cosmic mother lode delivered by NASA’s Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer mission.
This seven-year journey, known in astronomical parlance as OSIRIS-REx, brought the goods home via a sample return box that came to a complete halt on September 24, 2023, and parachuted into a remote area of the Department of Defense’s Utah. Testing and Training Range. These remotely retrieved samples are believed to contain remnants from the formation of the solar system 4.5 billion years ago.
Space.com caught up with two leading scientists who are currently busy uncovering what these dark asteroid particles illuminate and unraveling how these materials exported from Bennu came to be. But what insights do they also have into the origin of the worlds in our solar system, including Earth?
Relating to: OSIRIS-REx team finds NASA’s first asteroid sample rich in carbon and water
pristine reservoir
The scene is the University of Arizona’s Kuiper-Arizona Astromaterial Analysis Laboratory. Researchers there are using tools to investigate what the OSIRIS-REx collections tell them down to the atomic scale.
To start, University of Arizona scientists took 200 milligrams (about seven thousandths of an ounce) of a sample of asteroid Bennu for analysis.
“We have more than 1,000 particles larger than half a millimeter, we have 28 particles larger than a centimeter, and the largest particle is 3.5 centimeters,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona. “So it’s a great collection full of really big rocks.”
Bennu samples contain abundant water trapped in minerals such as clay and are also rich in carbon, nitrogen, sulfur and phosphorus. OSIRIS-REx samples represent the largest intact reservoir of such material on Earth.
“We’re going to be busy for a very long time,” Lauretta told Space.com. “This is a huge amount of sample for us,” he said, and samples of Bennu are now being studied around the world.
Different and different
What was found will be detailed next month at the 55th Lunar and Planetary Science Conference in The Woodlands, Texas. More than 70 science outcome summaries were submitted to this prestigious meeting, Lauretta said. “Starting in March, all of this will be announced to the world. That’s why the team is working quickly,” he said.
One of the early findings was that the asteroid material under study “looks isotopically distinct and distinct from everything else in our meteorite collection, which is exciting,” Lauretta said. “There is a realm of material that we will never be able to access if we rely solely on meteors,” Lauretta added.
Most meteors that fieryly fall into Earth’s atmosphere and are recovered are fragments of asteroids. However, it is not easy to locate the space rock from which they originate.
phosphate shell
Lauretta said the OSIRIS-REx samples have a phosphate shell never seen before in meteorites. These high phosphate concentrations have been detected on extraterrestrial ocean worlds, he said.
For example, Saturn’s moon Enceladus contains much higher levels of phosphates, the basic building blocks of life, than Earth’s oceans.
“Asteroid Bennu may be part of an ancient oceanic world. This is still highly speculative, but right now it’s the best clue I have to explain the origin of this material,” Lauretta said.
connect the dots
Unraveling the history of asteroid Bennu is a surreal undertaking, said Thomas Zega, a professor in the university’s Lunar and Planetary Laboratory and scientific director of the school’s Kuiper-Arizona Astromaterial Analysis Laboratory.
Zega highlights the decades devoted to the OSIRIS-REx mission, from a detailed proposal to intensive examination of asteroid samples in the laboratory.
“Honestly, rarely a day goes by where I don’t consider myself incredibly lucky to do this for a living,” Zega told Space.com. “I’m pinching myself. This is a blessing.”
Zega added that by any measure, the OSIRIS-REx mission was a remarkable success, “and to now be able to use some of the most advanced analytical tools on the planet to measure samples is pretty remarkable.”
Zega noted that missions like OSIRIS-REx, in addition to giving scientists information about Bennu’s origins, “have really helped us connect the dots between other meteorites in our terrestrial collection and perhaps the asteroids they came from.” “In the asteroid belt between Mars and Jupiter.”
Quick view
Zega was a member of the “quick look” team that attended the unveiling of the OSIRIS-REx sample return capsule after its delivery to NASA’s Johnson Space Center in Houston, Texas.
What was found by the curation team experts was a coating of fine-grained dust from the sampling maneuver on Bennu on the outside of the returning avionics deck and the Touch and Go Sample Collection Mechanism (TAGSAM) – the air filter-like mechanism. The end of the OSIRIS-REx robotic arm trapping most of the Bennu fragments.
One aspect of Zega’s surreal encounter with Bennu is that it leaves Texas and flies back to Arizona with a small pre-arranged sample piece from the asteroid.
After all, Zega’s express courier missions are due to the University of Arizona being a nearly 20-year operating base for moving OSIRIS-REx from proposal to ballistic entry of asteroid material.
shroud of darkness
“There was no way it was going in checked baggage! It went in my backpack that I carried on the plane. It was a small amount of stuff, in a bag, which itself was sealed in a bottle filled with nitrogen. So it was all protected,” Zega recalled.
The first thing Zega did after landing in Tucson at night was place the sample in a dry nitrogen box at the university laboratory for preservation and preservation.
“Then I went home, had dinner and went to sleep,” Zega recounted.
Zega said he was joking that everything was under darkness. “No one knew that someone had 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, the OSIRIS-REx TAGSAM head filled with Bennu fragments was fully opened by NASA curators. This final step was slow to be achieved due to several problematic fasteners that prevented the total payload of the asteroid collections from being visible to the eye.
It will now release a catalog of all Bennu samples later this year, allowing scientists and institutions worldwide to request the spacecraft to study Bennu bites.
Meanwhile, Lauretta and Zega, along with their colleagues, are intensively evaluating Bennu samples.
Teams of university students and faculty are leveraging a wide range of capabilities, from optical and electron microscopes to a newly acquired instrument.
A powerful nanoSIMS instrument is up and running, providing stunning glimpses of isotopes (different variations of atoms) in the Bennu sample to help interpret how each component emerged.
“A lot of good things are going to happen in the next few months,” Lauretta said. “Then stay tuned.”