NASA selected the final four candidate sample sites in August 2019, named Nightingale, Kingfisher, Osprey, and Sandpiper.[50] On 12 December 2019, they announced that Nightingale had been selected as the primary sample site and Osprey was selected as the backup site.[51] Both were within craters, with Nightingale near Bennu's north pole while Osprey was near the equator.[52]