Automated Tour Design in the Saturnian System, Assessment of dynamical models for transitioning from the Circular Restricted Three-Body Problem to an ephemeris model with applications

Automated Tour Design in the Saturnian System Future missions to Enceladus would benefit from multi-moon tours that leverage V_∞ on resonant orbits to progressively transfer between moons. Such resonance hopping trajectories present a vast search space for global optimization due to the different combinations of available resonances and flyby velocities. The proposed multi-objective tour design algorithm optimizes entire moon tours from Titan to Enceladus via grid-based dynamic programming, in which the computation time is significantly reduced by discretization of the design variables and pre-computation of a database of V_∞-leveraging transfers. The result unveils a complete trade space of the moon tour design to Enceladus, and the obtained solution is validated in a full-ephemeris model. Assessment of dynamical models for transitioning from the Circular Restricted Three-Body Problem to an ephemeris model with applications While the Circular Restricted Three-Body Problem (CR3BP) provides useful structures for various applications, transitioning the solutions from the CR3BP to a higher-fidelity ephemeris model while maintaining specific characteristics remains non-trivial. An analytical approach is leveraged to provide additional insight on the perturbations that are present in an ephemeris model. For the Earth–Moon CR3BP, pulsation of the Earth–Moon distance and solar gravity are identified as key components contributing to the additional accelerations, where patterns are illustrated through simplified mathematical relationships and graphics. Utilizing these findings, capabilities and limitations of two intermediate models, the Elliptic Restricted Three-Body Problem and the Bi-Circular Restricted Four-Body Problem, are assessed within the context of transitioning from the CR3BP to a realistic ephemeris model. A sample transition process for Earth–Moon L_2 halo orbits is provided, leveraging the insight from the proposed analytical approach.