Science orbits in the Saturn-Enceladus circular restricted three-body problem with oblate primaries

Abstract: This contribution investigates the properties of a category of orbits around Enceladus. In a previous investigation, a set of heteroclinic connections were designed between halo orbits around the equilibrium points L1 and L2 of the circular restricted three-body problem with Saturn and Enceladus as primaries. The geometrical characteristics of those trajectories makes them good candidates as science orbits for the extended observation of the surface of Enceladus: they are highly inclined, they approach the moon and they are maneuver-free. However, the low heights above the surface and the strong perturbing effect of Saturn require a study of the influence of the polar flattening of the primaries. Therefore, those solutions are here reconsidered with a dynamical model that includes the effect of the oblateness of Saturn and Enceladus, separately and in combination. The dynamical equivalents of the halo orbits around the equilibrium points L1 and L2 and their stable and unstable hyperbolic invariant manifolds are obtained in the perturbed models, and maneuver-free heteroclinic connections are identified. A comparison with the corresponding solutions of the unperturbed problem shows that qualitative and quantitative features are not significantly altered in the perturbed model. The results confirm the scientific value of the solutions obtained in the classical circular restricted three-body problem and suggests that the simpler model can be used in a preliminary feasibility analysis.