Once OSIRIS-REx has landed, a robotic sampling arm will perform Touch-And-Go (TAG) collection. The mission is to collect at least two ounces, or 60 grams, of rocky material. If the first TAG attempt in October does not collect enough material, OSIRIS-REx has onboard nitrogen charges to power two more attempts.
The spacecraft is scheduled to depart Bennu in 2021. It will deliver the collected sample to Earth on September 24th, 2023. While that’s still two years away, NASA has already made useful discoveries through OSIRIS-REx. For instance, NASA has spotted water on the asteroid, and we now know that Bennu is spewing particles into space. The team has also produced some of the highest resolution images of a planetary body ever.
NASA is also trying to get its hands on some lunar dirt from the Moon, but for that, the agency will turn to private companies.