Long lifetime orbits for the observation of Europa

The lifetime of a probe moving at low altitude around Europa is strictly correlated, other than to the effects due to the interaction with Jupiter’s magnetic field, but also to the eccentricity variations of its orbit because of a possible collision with the lunar surface. Thus, the knowledge of such variations plays a key role in designing missions that provide remotely sensed images of this moon at high spatial resolution. Accordingly, the behavior of this orbit element has been investigated here, taking into account the nonperfect coplanarity between the orbital plane of Jupiter, in its relative motion with respect to Europa, and the equatorial plane of the moon. The study has been conducted considering a double-averaged expression for the disturbing potential coming from the terms J2 and C22 of Europa’s gravitational field plus Jupiter’s gravity gradient. In this context, also to guarantee extended latitudinal coverage of the moon, the attention has been focused mainly on high inclination orbits. The results have highlighted the possibility of considerably extending the lifetime by choosing appropriately the initial conditions on the argument of pericenter of the orbit probe.