The fact that OSIRIS-Rex was designed to identify sample sites with an 82-foot radius made things even more difficult. To be able to find four boulder-free areas, the mission team had to adjust the spacecraft's sample site identification process to be able to detect sites with a radius of 16 to 33 feet. The scientists also had to give its navigation capabilities an accuracy boost to be able to target smaller sites than expected.

The OSIRIS-Rex team stuck to the mission's Egyptian-themed naming scheme and christened the four sites Nightingale, Kingfisher, Osprey and Sandpiper -- all birds native to Egypt. They vary in geological features: Nightingale contains fine-grain dark materials, Kingfisher has hydrated minerals, Osprey may have carbon-rich materials, while Sandpiper could yield water-rich samples. OSIRIS-REx will take close-up images of the four sites and analyze them in detail this fall. That will provide the mission team the data it needs to choose the primary and backup sample sites in December.