Optical Navigation for the DARŢ Mission

The DART mission launched on November 24th, 2021. The goal of this technology demonstration mission was to test orbital deflection through kinetic impact as a method of defense against potential asteroid or comet hazards. DART successfully impacted the 180-meter-diameter asteroid Dimorphos on September 26, 2022. The precise targeting needed to hit such a small body required optical navigation (Opnav) during the final month of the approach to provide information about the satellite-relative spacecraft position in directions perpendicular to the line-of-sight. In this paper we justify the need for Opnav, describe the Opnav image processing procedures and testing done in flight, and present results of the Opnav imaging campaign and the overall navigation of DART up to the moment of impact, where Opnav measurements with an accuracy of 0.05 pixels allowed a final navigation delivery within 1 km of Dimorphos, well within the requirement of 15 km.