At the end of last month , NASA ’s spacecraft OSIRIS - REx entered into arecord - interrupt orbital insertion , just 1.75 klick ( 1.09 miles ) from the centre of the asteroid Bennu , which is itself just 492 meters ( 1,614 animal foot ) across . This is the closest orbit ever achieve around a heavenly body , as well being the smallest objective every orbited .
During this phase , known as Orbital A , the arrangement are not actually collecting any scientific data but the NavCam 1 is . This tolerate the team behind the missionary post to tail the course that the spacecraft is taking around the asteroid , and it permit us to getthe best viewsof Bennu ’s southerly hemisphere yet .
This approaching is called Optical Navigation and the two “ OpNav ” images were taken on January 17 , each with an pic time of 1.4 milliseconds . The images have been adjust for contrast make up details of the clumpy surface more visible . The particularly striking boulder seen in the two images is 50 meters ( 165 feet ) across .
OSIRIS - REx ’s finish is not just observational though . In summer 2020 , the spacecraft will get extremely close to the asteroid and stretch out a appeal arm to catch a sample of regolith , the loose land on the surface of Bennu . To achieve this nigh - touchdown , researchers need to know everything there is to know about the asteroid .
For this reason , OSIRIS - REx is proceed to map the surface of the asteroid in extreme detail as well as studying its make-up to find the best spot for sampling - collecting . But the orbital phase will also refine measurements related to the mass and gravity of Bennu . The asteroid ’s gravity is extremely weak ( roughly 5 - millionth of Earth ’s own ) so even unaccented forces like thermic force per unit area from Bennu or solar radiation syndrome can push the ballistic capsule around , which means the team needs to keep an center on the movement of OSIRIS - male monarch and be ready to make small adjustments .
The investigation is currently91 million kilometers(less than 57 million knot ) from Earth and its detailed study of Bennu will begin in slightly less than a month . OSIRIS - REx is scheduled to vanish back to Earth once the sample has been collected , arriving back in 2023 .
