Planetary exploration of Saturn moons Dione and Enceladus

Abstract

Search for habitability in moons of Outer planets, requires presence of sources of energy. Dissipation from tidal forces is a major energy source in evolution of Icy moon systems. Heating always accompanies dissipation but, in case of tidal heating, it will additionally present complex spatial distribution, reflecting on a multi-layer structure in the particular case of Icy moons. Subsurface oceans are a generic feature of large icy bodies at some point in their evolution. A standard interior model for Icy moons consists of an outer solid (ice) layer, an intermediate liquid layer, and a solid (rocky) core. As a satellite rises a tide on its planet, they exchange angular momentum, affecting satellite orbit and planet spin; the moon gains orbital energy at the expense of the planet rotational energy. A complex 3-body paradigm, Laplace resonance, involves two (or more) moons of a planet, forming by differential expansions of orbits by tidal torques. At Jupiter, moons Io, Europa, and Ganymede are in 1:2:4 resonance.