The primary objective of the Origins, Spectral Interpretation, Resource
        Identification, and Security-Regolith Explorer (OSIRIS-REx) mission is to
        return pristine samples of carbonaceous material from the surface of a primitive
        asteroid. The target asteroid, near-Earth object (101955) Bennu, is the most
        exciting, accessible, and volatile- and organic-rich remnant from the early Solar
        System. OSIRIS-REx returns a minimum of 60 g of bulk regolith and a separate
        26 cm2 of fine-grained surface material from this body. Analyses of these
        samples provide unprecedented knowledge about presolar history, from the
        initial stages of planet formation to the origin of life. Prior to sample acquisition,
        OSIRIS-REx performs comprehensive global mapping of the texture, mineralogy,
        and chemistry of Bennu, resolving geological features, revealing its geologic
        and dynamic history, and providing context for the returned samples. The
        instruments also document the regolith at the sampling site in situ at scales down
        to the sub-centimeter. In addition, OSIRIS-REx studies the Yarkovsky effect, a
        non-Keplerian force affecting the orbit of this potentially hazardous asteroid
        (PHA), and provides the first ground truth for telescopic observations of carbonaceous
        asteroids.