Images obtained by the OSIRIS-REx spacecraft showed traces of oxygen and hydrogen molecules on Bennu, suggesting that the asteroid possibly was in contact with a body of water.

The mission team, led by researchers at the University of Arizona, presented their key findings at the Annual Fall Meeting of the American Geophysical Union, or AGU, in Washington DC on Dec. 10.

The images were collected using OSIRIS REx's two spectrometers called the Visible and Infrared Spectrometer (OVIRS) and Thermal Emissions Spectrometer.

History Of Water

Oxygen and hydrogen bonds called hydroxyls were found on the asteroid's rocky areas, suggesting that it is likely that the liquid formation is also present globally. The team concluded that its sheer size is scientifically unable to hold water, which led the scientists to believe that the water could have been from Bennu's parent rock.

This discovery opens up new possibilities in understanding the structural composition of the asteroid.

"It is very exciting to see these hydrated minerals distributed across Bennu's surface, because it suggests they are an intrinsic part of Bennu's composition, not just sprinkled on its surface by an impactor," Ellen Howell at the UA's Lunar and Planetary Laboratory said.

Additional data from the OSIRIS-REx Camera Suite confirmed the team's earlier prediction of Bennu's shape. Estimations done by Michael Nolan, the OSIRIS-REx science team chief, were almost exact as the asteroid's actual diameter, inclination, and rotation rate.

The preliminary images were taken on November, and 3D mapping showed features of the asteroid as small as 6 meters. OSIRIS-REx Camera Suite projected that Bennu is approximately 50 meters in height and 55 meters in width.

Ideal Exploration Subject

Bennu is proving itself to be an ideal subject for the mission, as the OSIRIS-REx team has not yet encountered impossible issues with it.

"The spacecraft is healthy and the science instruments are working better than required," said OSIRIS-REx principal investigator Dante Lauretta.

Scientists will be able to further study Bennu when the spacecraft returns from its mission on 2023 with actual samples.

OSIRIS-REx is scheduled for its first orbital flight on Dec. 31 until mid-February 2019. Bennu will be the smallest cosmic body to be orbited by a spacecraft and the closest orbit of a planetary body by a spacecraft at approximately 1.4 kilometers to 1.24 kilometers from the center of Bennu.