Gravity and Radio Science Investigation at the Moons of Uranus to Reveal Subsurface Oceans and Characterize Interior Structures

The prospect that the five major moons of Uranus could host subsurface oceans makes them high-priority targets for future exploration. Different techniques can be used to search for deep oceans in these objects. Here, we focus on ocean detection and characterization from measurements of the moons’ response to the gravitational tides and librations generated by Uranus forcing. We simulate the gravity and radio science investigations of a future mission by assuming different realistic trajectories and payload specifics of the anticipated Uranus Orbiter and Probe. A key finding is that observations of Umbriel’s tidal response can provide robust evidence of the existence of a subsurface ocean at that moon. For all the moons except Oberon, measurement of the forced librations can also provide a strong tool to test whether the oceans exist. Because of the challenges associated with detecting cold oceans through magnetic induction, gravity and radio science will provide powerful tools to understand whether oceans were preserved from freezing throughout the evolution of the moons.