Dawn's Exploration of Vesta and Ceres: Mission Design and Navigation Challenges and Lessons

The Dawn spacecraft was the first to orbit two separate distant celestial des-tinations, an achievement made possible by its Ion Propulsion System. Its solar-electric propulsion system enabled the mission to achieve the high delta-V requirements necessary for visiting and orbiting multiple targets, all while staying within the cost constraints of NASA's Discovery Program. The interplanetary cruise phase of the mission relied on continuous IPS thrusting for weeks or months at a time. Orbit transfers were conducted us-ing a series of maneuvers, a departure from traditional methods used with chemical propulsion systems. This unique approach required innovative mission design and navigation processes. This paper outlines the mission design challenges, navigation strategies, and key lessons learned from the Dawn mission.