Because high resolution snaps show asteroid Bennu is actually made up of rocks, not sand as scientists initially predicted – and this poses a problem for the Osiris lander which is about to touch down on the surface. Indeed, the shocking reveal has stunned the world of science.
NASA’s probe Osiris-REX has mapped the asteroid’s unique surface ahead of next year’s planned landing.
But the ship was loaded with tools to land on sand and collect a “beach-like sand substance” – the hyper rocky terrain has now thrown the scientists.
NASA chief Rich Burns said: “Although Osiris-REX was designed to collect a sample from an asteroid with a ‘beach-like’ area.”
But NASA has been delighted with the Osirs mission so far
Having launched in September 2016, the probe reached the proximity of the asteroid in December 2018.
The 20ft machine can travel up to 19,000mph and bosses are confident the probe will cope with the unexpected terrain.
Mr Burns said: “The extraordinary in-flight performance to date demonstrates that we will be able to meet the challenge that the rugged surface of Bennu presents.
“That extraordinary performance encompasses not only the spacecraft and instruments, but also the team that continues to meet every challenge that Bennu throws at us.”
Nightingale, one of the potential landing sites, is located in the north of the asteroid, with information suggesting material there would be good for collection.
Kingfisher, another proposed landing site, is surrounded by large boulders, with a small 8 meter crater to land in.
But the area has a strong spectral signature which indicates to experts an abundance of hydrated material.
Tensions have risen between a site that is safe for the ship to land versus the scientific gain and interest.
Samples will be collected by the Touch and Go Sample Acquisition Mechanism (TAGASM) which uses a 3.4 meter arm.
When this touches the surface, short nitrogen bursts will stir materials for collection.
Once the samples have been collected, the ship will leave the asteroid in March 2021, with capsules returning to Earth in September 2023.
Dante Laurette from 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.”