NASA's OSIRIS-REx

NASA to Capture Rich Carbon-Dust from a Former Water World

On October 20^th, after several years of patient study of its cryptic target, NASA’s 800$ million spacecraft named OSIRIS-REx (short for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is finally ready to take a flight to the near-Earth asteroid ‘Bennu’ and sweep some dust and pebbles along. The encounter which is about 334 kilometers away from Earth is going to last for about 10 seconds.

Source: NASA

If this mission turns out to be successful, NASA can get up to 1 kg of carbon-rich materials by the time of its return to Earth in 2023. Since OSIRIS-REx’s return in 2018, Bennu has shown a lot of changes, and some of them are quite surprising. The 500-meter-wide asteroid was not smooth, as expected, but scattered with more than 200 large boulders that could upset the sampling maneuver. And often, the asteroid even ejects coin-sized pebbles which are probably driven by meteoroid impact or solar heating. Because of this, the team is forced to target an area just 16 meters across for collecting samples, ten times smaller than originally planned.

Bennu; Source: NASA

"Bennu has not made things easy for us," says Mike Moreau, the mission's deputy project manager at NASA's Goddard Space Flight Center to sciencemag.com

Despite the organized/planned challenge, the boulders contain a prize: veins of carbonate minerals thicker than your hands, the team reports in one of six studies published on 8th in Science and Science Advances. The minerals, which precipitate out of hot water, popped out of data gathered during a close flyby of light-colored boulders near the target site, called Nightingale.

Bennu’s surface; Source: Universe Today

Researchers believe the veins grew in channels of fluid circulating within Bennu's parent body, 4.46 billion years ago soon after the dawn of the Solar System a larger planetesimal is thought to have formed beyond Jupiter's orbit, before being smashed apart in the asteroid belt within the last billion years. Heat from the decay of radioactive elements in its interior presumably drove the churning, and the presence of so much carbonate "suggests large-scale fluid flow, possibly over the entire parent body," says Hannah Kaplan, a planetary scientist at Goddard who led the work.

“This ancient water world is consistent with the idea that objects like Bennu delivered much of Earth's water when they struck the planet billions of years ago,” says Dante Lauretta, the mission's principal investigator and a planetary scientist at the University of Arizona. The veins also suggest watery bodies like Bennu were a cauldron for the organic chemistry that generated the amino acids and other unusual prebiotic compounds found in carbon-rich meteorites.