Fig. 3

Illustration of the phenomenon of forced libration and tidal acceleration (upper panel). The libration acceleration \({\mathbf {a}}_{libration}\) leads to periodic acceleration and deceleration of the satellite’s rotation rate \(\Omega _0\), which results in the so-called libration angle \(\Delta \Phi\). The tidal acceleration, \({\mathbf {g}}_{tide}\) acts between the mother planet and the satellite and leads to a deformation of the satellite’s surface. While the orbit rotation rate \(\Omega _0\) generates a constant offset on the rotation rate sensor recording, the libration modulates this offset in a sinusoidal shape with a period of \(T_{libration}\). From existing interior models of the satellite we can constrain the minimum (\(\Omega _{min}\)) and the maximum (\(\Omega _{max}\)) expected libration amplitudes (lower panel)