NASA's OSIRIS-REx probe finds evidence of water on its target asteroid Bennu

NASA appears to have picked the right rock for its first-ever asteroid-sampling mission OSIRIS-REx.The probe arrived on asteroid Bennu just last week, and in a period of days, found evidence of water-rich minerals on the asteroid, a NASA statement said.The discovery indicated that water in its liquid form was abundant in the interior of the celestial body Bennu was once part of. Astronomers studying the space rock think that this parent rock was a 100-kilometre-wide member of the main asteroid belt that falls between Mars and Jupiter.One of they key objectives from the mission is to give scientists a window into understanding the early evolution of our solar system and what asteroids like Bennu may have contributed to the presence of primitive life or water on Earth.This makes the newest discovery a big deal for the OSIRIS-REx team.[caption id="attachment_5706841" align="alignnone" width="1280"]

This image of asteroid Bennu is made from 12 PolyCam images collected on 2 December by OSIRIS-REx from a distance of 24 kilometers. Image: University of Arizona[/caption]"We targeted Bennu precisely because we thought it had water-bearing minerals and — by analogy with the carbonaceous chondrite meteorites that we've been studying — organic material," Dante Lauretta, OSIRIS-REx principal investigator form the University of Arizona, was reported to have said by Space.com."That still remains to be seen — we have not detected the organics — but it definitely looks like we've gone to the right place," Lauretta added.The $800-million-OSIRIS-REx mission launched in 2016 and only began its approach towards the asteroid in August this year. Over the weeks since then, OSIRIS-REx's onboard instruments picked up signatures of hydroxyl groups — molecules that have hydrogen and oxygen in them — which are a key indicator of moisture. Researchers think these hydroxyls are abundant on Bennu, locked in the form of clay minerals.

NASA has also released the OSIRIS-REx's best look at Bennu yet, taken just before the spacecraft's arrival at the asteroid. It tells of Bennu's rugged, boulder-laden surface in unprecedented detail.While the nature of Bennu's surface could complicate the sample-grab part of the OSIRIS-REx mission, the scientists are quite sure they will find a suitable sampling site by July 2020, until which the probe is otherwise occupied with collecting science data and measurements from the asteroid."We have an awesome asteroid to explore," Lauretta said. "It's a dream come true, and an honor and a privilege to be able to lead a program like this for NASA and for the United States and, really, for the world."