The Feasibility of a Galileo-Style Tour of the Uranian Satellites

Gravity-assist trajectories have been a key to outer solar system exploration. In particular, the gravity-assist tour of the Jovian satellites has contributed significantly to the success of the Galileo mission. A comparison of the Jovian system to the Uranian system reveals that the two possess similar satellite/planet mass ratios. Tisserand graphs of the Uranian system also indicate the potential for tours at Uranus. In this paper we devise tour strategies and design a prototypical tour of the Uranian satellites, demonstrating that tours at Uranus are feasible. In an example tour that launches in 2008, a series of flybys with Titania are used to reduce the inclination (14 deg at arrival) to permit encounters with Oberon, Ariel, and Umbriel. The tour involves over 40 flybys and ends after two years with a hyberbolic excess velocity with respect to Ariel of 0.92 km/s, which permits insertion into orbit about Ariel.