On Monday, the scientific community got its first description of that precious, exotic stuff, revealed by the mission’s top scientist, Dante Lauretta, at the fall meeting of the American Geophysical Union in San Francisco.

Lauretta, a planetary scientist at the University of Arizona, showed slides with a long list of intriguing molecules, including carbon-based organics, in the grains and pebbles retrieved from Bennu. They will shine light on the molecular building blocks of the solar system and “maybe — still early phase — maybe insights into the origin of life.”

This analysis has only just started. The team has not yet released a formal scientific paper. In his lecture, Lauretta cited one interesting triangular, light-colored stone, which he said contained something he’d never seen before in a meteorite.

“It’s a head-scratcher right now. What is this material?” he said.

In an interview after the lecture, Lauretta said almost 5 percent of the sample is carbon. “That is a very carbon-rich sample — the richest we have in all our extraterrestrial material. … We’re still unraveling the complex organic chemistry, but it looks promising to really understand: Did these carbon-rich asteroids deliver fundamental molecules that may have gone on to contribute to the origin of life?”

The laboratory analysis is searching for other molecules and compounds important to life on Earth, such as amino acids, lipids, sugars and the bases of the genetic code, Lauretta said, adding that the results so far are exciting. The team is still refining its report, which will be discussed at a scientific meeting early next year, he said.

NASA chose to send a probe to Bennu in part because it is potentially the most dangerous asteroid in the solar system. Its orbit around the sun is similar to that of Earth. Every six years the rock, which is about three-tenths of a mile in diameter (large enough to get your attention, but not nearly big enough to deliver an extinction-level impact) crosses our planet’s orbital path.

A calculation published in 2021 estimated that Bennu has a 1-in-2,700 chance of slamming into Earth in September 2182. That estimate will be refined after the asteroid makes a close pass in 2135.

On the very off chance that earthlings will want to knock the rock off course, they’d definitely like to know precisely what they’re hitting. A telescope doesn’t deliver as much information as a robotic visitor. Hence, OSIRIS-REx (which stands for Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer).

Even before the scientists began analyzing the samples, one thing had been firmly established: Bennu is very, very black.

“It’s super black. It’s so black it’s hard to take a picture of,” project scientist Jason Dworkin said in advance of the meeting. The material includes “all kinds of different shades of black” — plus mysterious glints of yellow and red and pink, he added.

A career’s worth of material

NASA launched the OSIRIS-REx spacecraft in 2016, and it reached Bennu in 2018. In 2020 it performed a series of delicate maneuvers to touch the asteroid with a sampling device on the end of a robotic arm. The arm plunged unexpectedly deep into the asteroid, which turned out to be what scientists call a rubble pile, made of loosely aggregated material held together by gravity.

The spacecraft then returned to the vicinity of Earth and released a capsule containing the sample. On Sept. 24 it landed almost perfectly on target on a military bombing and training range in western Utah. The capsule showed no sign of stress from its long voyage and, indeed, sat upright on the desert floor just a few convenient paces from a road.

The carefully sealed capsule was then transported to NASA’s Johnson Space Center in Houston. Next came the very delicate work of retrieving the material from Bennu. Inside the capsule was a canister that, in turn, held a sampling device. The canister was opened, but the sampling device proved uncooperative. It was sealed by 35 specially designed fasteners, two of which wouldn’t budge.

NASA is designing a new tool that should get the job done in coming weeks. In the meantime, according to a NASA blog post, the sampling device has been transferred to another container and is “surrounded by a sealed Teflon bag to make sure the sample is kept safe in a stable, nitrogen-rich, environment.”

Still, no one panicked: A member of the team realized that it would be possible, using tweezers and scoops, to retrieve some of the trapped material from inside the device. As a result, the team obtained 70 grams of sample, exceeding the official mission requirement of 60 grams.

“This is a career’s worth of material for thousands of researchers all over the world. So we’re ecstatic,” Lauretta said. “I fully expect the cosmochemistry community is going to go to town on this.”

“We’re getting a lot of information from a very small amount of sample,” NASA astrobiologist Danny Glavin said in advance of the meeting.

Bennu is a fragment of a larger object that was shattered during a collision early in the history of the solar system, scientists believe. The parent body, heated by radioactive decay, would have been warm enough for interior water to be in liquid form.

“If you add water, you can do a lot of interesting chemistry,” Glavin said.

It is not prejudicial to say that chemistry gets more interesting when it somehow produces a living thing. Paleobiologists know that life existed on Earth, as bacteria, at least 3.5 billion years ago — relatively soon after the planet survived a long period of violent bombardment from rocks that cluttered the solar system in its youth.

It’s unlikely that Bennu’s parent body had anything alive in it, but it may have cooked up interesting compounds akin to the ones that formed the building blocks of life on Earth, which, as Dworkin put it, “had to have started with chemistry that happens in space.”

Prebiotic chemistry, however, is a long way from a bacterium — “about as far as a bottle of vitamins from Thanksgiving dinner,” Dworkin said.

This space dirt has astrobiological import, though. By looking at prebiotic chemistry on Bennu, scientists will have a better idea what they are looking at if and when they find suspicious molecules elsewhere in the solar system, such as on Mars, Jupiter’s moon Europa or Saturn’s moon Enceladus.

“This is almost the perfect laboratory control from non-biological chemistry,” Glavin said. “This better prepares us for our search for life on Mars, or Europa or Enceladus — places that might have had life at one point.”