In this paper, the problem of fast low-energy halo-to-halo transfers between Sun-planet systems is discussed under ephemeris constraints. According to the structure of an invariant man- ifold, employing an invariant manifold and planetary gravity assist to save fuel consumption is ana- lyzed from the view of orbital energy. Then, a pseudo-manifold is introduced to replace the invariant manifold in such a way that more transfer opportunities are allowed. Fast escape and cap- ture can be achieved along the pseudo-manifold. Furthermore, a global searching method that is based on patched-models is proposed to find an appropriate transfer trajectory. In this searching method, the trajectory is divided into several segments that can be designed under simple dynamical models, and an analytical algorithm is developed for connecting the segments. Earth-Mars and Earth Venus halo-to-halo transfers are designed to demonstrate the proposed approach. Numerical results show that the transfers that combine the pseudo-manifolds and planetary gravity assist can offer significant fuel consumption and flight time savings over traditional transfer schemes.
The interest in the periodic orbits of the restricted three-body problem continues to grow for their significant practical application.This paper focuses on the interplanetary transfers between periodic orbits of two different three-body systems,whose invariant manifolds have no intersection in phase space.A novel design method is proposed to obtain the optimal transfer employing the invariant manifolds and planetary gravity assist.The periapsis Poincare map is used to analyze the periapsides of invariant manifolds.On the basis of hyperbola approximation,the impulses performed on the periapsis of invariant manifolds are calculated with a simple iterative algorithm.The propellant-efficient escape and capture trajectories can be found by comparing the impulses magnitudes corresponding to different invariant manifolds,which can provide the appropriate initial guess for optimization.Further,the trajectory design is formulated as an unconstrained optimization problem under the perturbed restricted three-body model.An efficient algorithm combining simplex method and differential correction is adopted to obtain the optimal solution.The validity of the proposed approach is demonstrated through several interplanetary low energy transfer trajectories.
