Asteroid Bennu samples suggest space rocks could have helped seed life on Earth

Bits of rock and dust brought back from the distant asteroid Bennu contain some of the chemical building blocks of life, NASA announced Wednesday, a discovery that strengthens the theory that asteroids could have brought ingredients for life to ancient Earth.

The findings don't show evidence for life itself, NASA said, "but they do suggest the conditions necessary for the emergence of life were widespread across the early solar system, increasing the odds life could have formed on other planets and moons."

Read more: Samples are "pathway to life."

The Bennu samples were retrieved by NASA’s OSIRIS-REx spacecraft in 2020. The robotic probe scraped 4.2 ounces of material from the asteroid and dropped them into Utah by parachute in a sealed container in 2023.

The samples are significant because they were obtained in space rather than taken from meteorites that have crashed into Earth. Exposure to the biosphere "complicates interpretation," the Nature Astronomy study said.

The samples have been analyzed by laboratories across the globe, reported the University of Arizona. They were found to contain "more carbon, nitrogen and ammonia than samples from asteroid Ryugu and most meteorites," according to a study by Nature Astronomy.

For example, Nature Astronomy reported that 14 of the 20 amino acids that life on Earth uses to make proteins were found in the Bennu samples.

Researchers also discovered all five nucleobases, which living things use to store and transmit genetic instructions in biomolecules such as DNA and RNA, in the samples, NASA said.

A second study by the journal Nature reported that samples showed Bennu's parent body – a larger asteroid that Bennu was once part of – likely contained brine, or salty, subsurface water.

That suggests brines may have played a part in places where prebiotic molecules, molecules that could have contribute to the origin of life, were formed. "This finding raises questions about whether similar molecules will be found in places like Jupiter’s moon Europa," the study said.

In January 2024, NASA's astromaterials curation team at Johnson Space Center in Houston revealed high-resolution photos of the materials from asteroid Bennu contained within the OSIRIS-REx sampler head. On Jan. 10, 2024, they removed two stubborn fasteners that prevented the team from opening the Touch-and-Go-Sample-Acquisition-Mechanism (TAGSAM) head.

The historic special delivery of the TAGSAM spanned seven years and 4 billion miles. It parachuted into a Utah desert site, and the estimated half-pound of rocks from the distant asteroid was sent to Houston for study.

You can zoom in on photos posted to the NASA website to see more detail.

OSIRIS-REx's van-sized craft visited Bennu, scraped and collected material from the asteroid’s surface and sealed it into a 3-foot-wide container equipped with a heat shield, called the Sample Return Capsule, for delivery to Earth.

The SRC landed within a 306-square-mile site in the Defense Department's Utah Test and Training Range, about 80 miles west of Salt Lake City, at about 11 a.m. EDT.

NASA livestreamed the landing.

What is OSIRIS-REx?

The spacecraft is powered by solar panels. Five science instruments mapped Bennu's chemistry and mineralogy to determine the effect of sunlight on the asteroid's orbit.

Cost of the mission, excluding launch, is $800 million.

OSIRIS-REx is an acronym for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. A timeline of significant events:

• Sept. 8, 2016: Launch.
• Sept. 22, 2017: Earth flyby.
• Dec. 3, 2018: OSIRIS-REx arrives at asteroid Bennu.
• Dec. 31, 2019: OSIRIS-REx begins orbiting Bennu.
• Oct. 20, 2020: Sample collected from Bennu.
• April 7, 2021: Final flyover of Bennu.
• May 10, 2021: OSIRIS-REx begins journey back to Earth.
• Sept. 24, 2023: Sample Return Capsule lands on Earth. OSIRIS-REx is renamed OSIRIS-APEX and sent to Apophis, a 1,100-foot-wide asteroid expected to pass Earth at a distance of 20,000 miles in 2029.
• Jan. 19, 2024: TAGSAM is opened and Bennu samples are photographed.
• April 2029: OSIRIS-APEX is scheduled to arrive at asteroid Apophis.

OSIRIS-REx was carried into space atop an Atlas V rocket from Cape Canaveral, Florida.

Why did OSIRIS-REx go to Bennu?

Bennu was studied to better understand other asteroids and their movements through space. Information gathered by OSIRIS-REx may help in development of future technologies to deflect asteroids that threaten to collide with Earth.

Bennu is considered one of the most potentially hazardous near-Earth asteroids in the solar system. It makes its closest approach to Earth every six years. In 2135 it could pass closer to Earth than the moon, according to NASA.

Bennu was discovered in 1999 and is believed to be part of a larger asteroid that collided with another space rock. It’s about one-third of a mile wide and is roughly the height of the Empire State Building.

Its black surface is packed with boulders and it orbits the sun every 14 months.

Bennu is rich in carbon and is believed to be a leftover fragment from the formation of the solar system, a time capsule of sorts that may help illuminate the origin of life.

After orbiting the sun for a year, OSIRIS-REx passed Earth and used its gravitational field as a boost toward Bennu.

Is this the first time samples have been taken from an asteroid?

Japan gathered microscopic grains from the asteroid Itokawa in 2010 and samples from the asteroid Ryugu in 2019.

A NASA spacecraft with solar wind particles slammed into the Utah desert and shattered in 2004, compromising the samples. A NASA capsule with collected comet dust landed intact in 2006.

Where are the Bennu samples being analyzed?

The samples from Bennu are being studied in a new laboratory at the Astromaterials Research and Exploration Science division, or ARES, at the Johnson Space Center.

Other laboratories are analyzing the samples, including the National History Museum in London, the Smithsonian Institution in Washington, Hokkaido University in Japan, and NASA's Goddard Space Flight Center in Maryland.

Johnson Space Center also contains samples from the moon, meteorites and orbital debris. The new lab will be restricted to Bennu samples to avoid cross-contamination with other collections.

The samples will be stored at Johnson, which holds the most extensive collection of astromaterials on Earth.

How did OSIRIS-REx collect samples?

OSIRIS-REx fired braking rockets to slow its speed to match Bennu's. It orbited the asteroid and began a months-long survey in October 2020. Extensive mapping, from an altitude of about 3 miles, determined where the sample was taken.

The spacecraft did not land on the asteroid. It got close enough to extend an 11-foot robotic arm and touch the surface for about 5 seconds.

A burst of nitrogen stirred up surface elements, which were captured by a screened sampler head – a pad about the size of an automobile air filter – at the end of the arm.

Scientists discovered the surface of Bennu is not solid but loosely packed. Instead of bouncing off the surface, the sampling head sank in with little resistance.

The sample was stowed in the onboard Sample Return Capsule.

OSIRIS-REx released the capsule about 63,000 miles from Earth at about 6:42 a.m. EDT. It plummeted to Earth and landed by parachute at the Utah Test and Training Range.

What's next for OSIRIS-REx?

OSIRIS-REx was renamed and is now traveling to Apophis, another near-Earth asteroid. The spacecraft's name was changed to OSIRIS-APEX for OSIRIS-APophis EXplorer.

CONTRIBUTING Doyle Rice, Paste BN; Rick Neale and Jamie Groh, Florida Today

SOURCE Paste BN Network reporting and research; NASA; Reuters; nature.com; asteroidmission.org, University of Arizona; space.com; planetary.org; spaceflight101.com