by Scientists thought asteroid Bennu's surface would be like a sandy beach, abundant in fine sand and pebbles, which would have been perfect for collecting samples.
Past telescope observations from Earth's orbit had suggested the presence of large swaths of fine-grain material called fine regolith that's smaller than a few centimeters.
But when the spacecraft of NASA's University of Arizona-led OSIRIS-REx asteroid sample return mission arrived at Bennu in late 2018, the mission team saw a surface covered in boulders.
The mysterious lack of fine regolith became even more surprising when mission scientists observed evidence of processes capable of grinding boulders into fine regolith.
Source
Past telescope observations from Earth's orbit had suggested the presence of large swaths of fine-grain material called fine regolith that's smaller than a few centimeters.
But when the spacecraft of NASA's University of Arizona-led OSIRIS-REx asteroid sample return mission arrived at Bennu in late 2018, the mission team saw a surface covered in boulders.
The mysterious lack of fine regolith became even more surprising when mission scientists observed evidence of processes capable of grinding boulders into fine regolith.
Source
