Robust Access to Uranus via Solar Electric Propulsion

The 2023 Planetary Science and Astrobiology Decadal Survey—Oceans, Worlds, and Life (OWL)—recommended a Uranus Orbiter and Probe (UOP) as the highest-priority next flagship mission. However, the concept presented in OWL baselined a 2031 launch, which is not compatible with a realistic projected funding timeline for UOP. Consequently, the OWL cruise trajectory, which took advantage of a favorable solar system alignment to perform an enabling Jupiter gravity assist, is no longer viable. In this work, cruise trajectories that use a solar-electric propulsion stage to reach Uranus, followed by a chemical-propulsion maneuver to capture into the Uranian system, are presented. Trade studies evaluating performance over a wide range of parameters are described. Trajectory suitability is evaluated not only on the basis of raw technical performance but also on risk-related factors, such as launch year robustness, missed-thrust robustness, and propulsion system availability.