NASA has picked out four likely landing sites for a spacecraft orbiting asteroid Bennu, a third-of-a-mile-wide space rock that has a distant chance of hitting Earth in 2066.
Since its arrival last December, the OSIRIS-REx spacecraft has mapped the entire asteroid to identify a landing site where it can collect a sample.
But the rocky surface of Bennu has made the process more difficult.
The asteroid’s boulder-filled exterior has made it complicated to pick out safe areas containing sample-able material, which must be fine enough – less than 1 inch in diameter – for the spacecraft’s sampling mechanism to ingest it.
Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson, said, ‘We knew that Bennu would surprise us, so we came prepared for whatever we might find.
‘As with any mission of exploration, dealing with the unknown requires flexibility, resources and ingenuity.
‘The OSIRIS-REx team has demonstrated these essential traits for overcoming the unexpected throughout the Bennu encounter.’
Bennu is thought to be rich in organic molecules dating from the start of the solar system.
Scientists believe that asteroids may have delivered the ingredients for life to the young Earth - and hope to analyse samples from Bennu to prove the theory.
They estimate there is a one-in-2,700 chance of the asteroid crashing into Earth 166 years from now.
If Bennu hit our planet, it would explode with more force than all the nuclear weapons detonated in history, and could start fires across an area four times the size of Britain.