OSIRIS REx Press Conference Live

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]

NASA planned to perform the first sampling in late August 2020;[53] NASA's originally planned Touch-and-Go (TAG) sample collection was scheduled for 25 August 2020, but was rescheduled for 20 October 2020, at 22:13 UTC.[54][55] On 15 April 2020, the first sample collection rehearsal was successfully performed at the Nightingale sample site. The exercise took OSIRIS-REx as close as 65 m (213 ft) from the surface before performing a back-away burn.[56][57] A second rehearsal was successfully completed on 11 August 2020, bringing OSIRIS-REx down to 40 m (130 ft) from the surface. This was the final rehearsal before the sample collection scheduled for 20 October 2020, at 22:13 UTC.[58][59]

At 22:13 utc, on 20 October 2020, OSIRIS-REx successfully touched down on Bennu.[60] NASA confirmed via images taken during sampling that the sampler had made contact. The spacecraft touched down within 92 cm (36 in) of the target location.[61][62] A sample of the asteroid which was estimated to weigh at least 2 ounces (57 grams) was collected by OSIRIS-REx following the touch down.[17] After imaging the TAGSAM head, NASA concluded that there were rocks wedged in the mylar flap that is meant to keep the sample inside, causing the sample to slowly escape into space.[63] In order to prevent further loss of the sample through the flaps, NASA canceled the previously planned spinning maneuver meant to determine the mass of the sample as well as a navigational braking maneuver, and decided to stow the sample on 27 October 2020 rather than 2 November 2020 as originally planned, which was completed successfully. The collector head was observed hovering over the Sample Return Capsule (SRC) after the TAGSAM arm moved it into the proper position for capture, and the collector head was later secured onto the capture ring in the SRC.[63]

When the head was seated into the Sample-Return Capsule's capture ring on 28 October 2020, the spacecraft performed a "backout check", which commanded the TAGSAM arm to back out of the capsule. This maneuver is designed to tug on the collector head and ensure that the latches – which keep the collector head in place – are well secured. Following the test, the mission team received telemetry confirming that the head was properly secured in the Sample-Return Capsule. Thereafter, on 28 October 2020, two mechanical parts on the TAGSAM arm were disconnected – these are the tube that carried the nitrogen gas to the TAGSAM head during sample collection and the TAGSAM arm itself. Over the next several hours, the mission team commanded the spacecraft to cut the tube that stirred up the sample through the TAGSAM head during sample collection, and separate the collector head from the TAGSAM arm. Once the team confirmed these activities were done, it commanded the spacecraft on 28 October 2020, to close and seal the Sample-Return Capsule, the final step of the sample stowage process of Bennu's samples.[64] To seal the SRC, the spacecraft closed the lid and then secured two internal latches. On inspecting images, it was observed that a few particles had escaped from the collector head during the stowage procedure, but it was confirmed that no particles would hinder the stowage process, since the team was confident that a plentiful amount of material remained inside of the head, more than the 60 g (2.1 oz) needed, and as much as 2,000 g (71 oz). The sample of Bennu was safely stored and ready for its journey to Earth. With the collector head secure inside the SRC, pieces of the sample would no longer be lost.[65]