English: OSIRIS-REx is a NASA mission to explore near-Earth asteroid Bennu and return a sample to Earth. Prior to arriving at Bennu, mission planners had expected the asteroid’s surface to consist largely of fine particulate material, similar to gravel. When OSIRIS-REx arrived in December 2018, however, it was greeted by a rocky world covered with boulders. This unexpected ruggedness means that there are few places on Bennu where OSIRIS-REx can safely touch down and collect a sample. After a year of studying the asteroid, the mission announced a primary sample collection site, which they designated “Nightingale,” along with a backup site called “Osprey.” In October 2020, OSIRIS-REx will descend to Bennu and attempt to collect up to four-and-a-half pounds of loose material, for return to Earth in 2023.