NASA Probe Spots Evidence Of Water On The Asteroid Bennu

Water On The Asteroid Bennu
Image source: NASA’s OSIRIS-REx/Twitter

Just a week after NASA’s OSIRIS-REx approached the asteroid Bennu, it has already discovered something of great interest to scientists. The probe found evidence of water on the asteroid Bennu.

The OSIRIS-REx mission launched in 2016 with the goal of exploring the asteroid Bennu, analyzing its properties and chemical composition, and sending back samples of it. Moreover, the mission could help scientists understand the kinds of materials which may have been carried to Earth by asteroids long ago.

NASA believes the make-up of the asteroid Bennu is similar to the asteroids scientists think carried water and organic material to Earth. The mission is currently surveying the asteroid and characterizing its motion in case its path ever crosses Earth’s orbit. Astronomers predicted earlier this year that Earth and Bennu may one day collide, or at least pass close by each other. After the NASA probe determines the asteroid’s trajectory, the probe should begin orbiting Bennu on Dec. 31. The asteroid could also help scientists learn how our solar system looked in its early days. As part of the mission, the spacecraft will take a sample of the asteroid and send it back to Earth via a return capsule.

Now just a week after the probe’s arrival at Bennu, NASA has announced that its OSIRIS-REx spacecraft found evidence of water on the asteroid Bennu. Unfortunately, it’s not the type of water they were hoping to find on an asteroid like Bennu or even anywhere else in the universe, but scientists say it is still a promising sign.

According to NASA, there is no sign of liquid water on the surface of the asteroid. However, the space agency believes Bennu’s surface may have been in contact with water at some point in the past, although the asteroid itself is too small to have ever hosted liquid water.

Currently, OSIRIS-REx is located 12 miles from the 1,600-foot-wide Bennu. The spacecraft is now using its instruments to study the asteroid. Data sets from OSIRIS-REx’s Thermal Emission Spectrometer and Visible and Infrared Spectrometer are enabling scientists to study the composition of the asteroid.

The spacecraft’s instruments detected “hydroxyls,” which are molecules of oxygen and hydrogen bonded together. However, these hydroxyls are bonded to other materials on the asteroid, so they do not consist of  liquid water. NASA believes the space rock interacted with a larger parent asteroid which did contain liquid water on its surface.

“The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” NASA scientist Amy Simon of Goddard Space Flight Center said in a news release. “When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”

Even though those are just hydroxyl groups, they still provide evidence of water on the asteroid Bennu. This discovery represents an early milestone in the OSIRIS-REx mission.