The research objective is to fly by a small near-Earth asteroid (NEA) to constrain its surface color and spectral properties, shape, density, and regolith distribution. The NASA Strategic Plan and NASA Science Plan emphasize asteroid studies: "Asteroids are not only important when they cross the Earth's orbit; studying asteroids can provide insights into the origins of the solar system." Such investigations are a key part of NASA's Global Exploration Roadmap and of NASA's strategy for the human exploration of space through NASA's Asteroid Initiative. Diminutive Asteroid Visitor using Ion Drive (DAVID) is a low-cost six-unit (6-U) CubeSat mission that significantly supports these scientific and human exploration goals. After launch on the Space Launch System (SLS) Exploration Mission-1, DAVID will fly by an NEA, 2001-GP2, which closely approaches Earth in 2020. Trajectory optimizations from the Mission Analysis Low-Thrust Optimization (MALTO) show that a 400-m/s delta-V allows a 2001-GP2 flyby in 2020. If the delta-V from the SLS injection is near the desired trajectory direction, the delta-V for flyby could be reduced. To date, NASA spacecraft have investigated eight asteroids: five flybys from four spacecraft, one mission (Dawn) investigating two asteroids from orbit, and one mission (NEAR-Shoemaker) both orbiting and landing. NASA also collaborated on flybys of two asteroids during the European Space Agency's Rosetta mission. DAVID will investigate an asteroid much smaller than any investigated by previous spacecraft missions and will be the first NASA mission to investigate an Earth-crossing asteroid—a category of great interest. (NEAR went to 433 Eros—an NEA, but an Amor type whose orbit never crosses that of Earth.) DAVID's instruments provide critical first-order data on 2001-GP2's size, shape, composition, and source region in the main belt, while scouting its rotational state and physical properties. The instrument set consists of wide- and narrow-angle cameras, a visible/near infrared spectrometer, and gravity measurement. The DAVID spacecraft fits a standard deployer as a 6-U CubeSat with a mass of 11.5 kg including 30% growth on dry mass. Compatibility with SLS safety and mission assurance considerations may not allow energetic propellants (e.g., solid rocket motors and compressed gases) to be on the vehicle, and hence the propellant must be inert. DAVID uses a 10-W electrospray thruster with a propellant-less cathode and a bellows salt tank. Development for the NASA Space Technology 7 (LISA Pathfinder) launch will bring the technology readiness level to 6 by the Critical Design Audit and a flight demonstration before launch. The mission is managed by the NASA Glenn Research Center (GRC)—a NASA center of excellence for all of the critical spacecraft technologies needed for DAVID: propulsion, power system, and advanced communications. In addition, GRC is experienced in managing space experiments and in building space hardware and is the technical lead for NASA Solar Electric Propulsion. Principal Investigator (PI) Dr. Geoffrey Landis is a member of the science teams for the Mars Pathfinder and Mars Exploration Rover missions, and he has designed and built hardware for several space missions. Collaborator Steve Oleson leads the GRC Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) spacecraft design team. Science PI Dr. Ralph Harvey has a long history of planetary materials research including geochemical, mineralogical, and physical studies of asteroidal and cometary materials (meteorites, micrometeorites, and samples from the Stardust mission). He is PI and field team leader for the Antarctic Search for Meteorites program and will lead a team of experienced collaborators to analyze DAVID imagery and spectra. The period of performance for this work is from October 2015 through October 2020.