The jackpot from a seven-year mission to bring back bits of an asteroid was unveiled on Wednesday.
NASA officials in Houston displayed images of salt-and-pepper chunks of rock and particles of dark space dust that were brought back to Earth from the asteroid, Bennu, and described initial scientific observations about the material. The mission, Osiris-Rex, concluded in September when a capsule full of asteroid was jettisoned through Earth’s atmosphere and recovered in the Utah desert.
The first pieces of materials that leaked outside the container were analyzed using a variety of laboratory techniques, revealing just the earliest findings.
Scientists found water molecules trapped in clay minerals — water from asteroids similar to Bennu could have filled Earth’s oceans.
“The reason that Earth is a habitable world, that we have oceans and lakes and rivers and rain, is because these clay minerals, like minerals, like the ones we’re seeing from Bennu, landed on Earth four billion years ago,” Dante Lauretta, the mission’s principal investigator, said during a NASA event on Wednesday
The materials also contained sulfur, key for many geological transformations in rocks. “It determines how quickly things melt and it is also critical for biology,” said Dr. Lauretta, who displayed microscopic images and 3-D visualizations of the material. The scientists also found magnetite, an iron oxide mineral that can play an important role as a catalyst in organic chemical reactions.
“We’re looking at the kinds of minerals that may have played a central role in the origin of life on Earth,” Dr. Lauretta said.
The samples are also chock-full of carbon, the element that is the building block for life.
“We picked the right asteroid,” said Daniel Glavin, a NASA astrobiologist working on the mission. “And not only that, we brought back the right sample. This stuff is an astrobiologist’s dream.”
The NASA mission that collected the samples was named Osiris-Rex — a shortening of Origins, Spectral Interpretation, Resource Identification and Security, Regolith Explorer. it concluded on Sept. 24 when a capsule containing the bits of Bennu landed under a parachute in the Utah desert. From there, the capsule was taken to the Johnson Space Center in Houston. When technicians there removed the lid of the sample canister, they found dark powder and sand-size particles.
While providing a quick, early look at what’s inside, that material has also slowed the work to get into the main compartment of the sample-collecting tool. “There was so much extra material it slowed down the careful process of collecting and containing the primary sample,” said Francis McCubbin, the astromaterials curator at the Johnson Space Center.
Osiris-Rex launched in 2016 and arrived at Bennu a couple of years later, making observations at a distance.
Bennu, discovered in 1999, is a carbon-rich asteroid that is almost black in color. It is about 1,600 feet wide. That compares to the Empire State Building, which is 1,454 feet tall including the antenna at the top. The carbon-rich materials are intriguing because asteroids like Bennu might have seeded Earth with the building blocks for life.
In October 2020, Osiris-Rex pogo-sticked off the asteroid using its sampling tool, which looks like an automobile air filter at the end of a robotic arm, to pick up the rock samples. A burst of nitrogen gas knocked up rocks and dust into the collection filter, and then Osiris-Rex slowly backed away without landing on Bennu.
The sampling arm got more material than it expected, and a flap on the collection tool was jammed open. The collected rock and dirt started escaping back into space. Mission managers decided to stow the sample as quickly as they could. In May 2021, the spacecraft started heading back to Earth.
Bennu is categorized as a near-Earth asteroid, and scientists say there is a 1-in-1,750 chance it could slam into Earth during a series of very close passes between 2175 and 2199.
Bennu is not large enough to cause planet-wide extinctions. But it would be catastrophic at the point of impact.
While the mission has concluded, the spacecraft’s journey is not over yet. After releasing the return sample capsule, the main spacecraft swerved away from a collision with Earth and is now headed toward Apophis, a 1,000-foot-wide asteroid that will fly within 20,000 miles of Earth in 2029. Soon after that close approach, the spacecraft, now renamed Osiris-Apex — short for Origins, Spectral Interpretation, Resource Identification and Security-Apophis Explorer — will enter orbit around Apophis.