Optimal Trajectories in the Earth-Moon CR3BP system

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Abstract

The aim of this investigation is to improve the first stage of mission analysis on trajectories in the Circular Restricted Three-Body Problem (CR3BP). This will be achieved by developing a versatile tool that can optimize any transfer in the CR3BP in terms of ΔV and time of flight. Hence, the output will not be
a single solution, but a Pareto front with multiple non-dominated solutions that range in duration and propellant consumption, such that the user can easily identify the one that better suits his/her particular mission requirements.
The tool considers three types of arcs: direct transfers, manifold trajectories and flyby arcs which can be combined in any way to connect the departure and destination orbits. These can be defined as Keplerian orbits or CR3BP periodic solutions, including Lyapunov, Halo orbits or NRHOs. This is done in a very intuitive way thanks to the careful selection of design variables. Therefore the developed tool can be used by designers that do not have a large amount of experience solving trajectory optimization problems in the CR3BP.
In order to demonstrate the capabilities of the tool, two specific transfers were optimized. In both cases, the Pareto front is obtained with the combination of optimal solutions that include direct transfers, and manifold and flyby arcs. First, a LEO to L2 Halo orbit with Az = 2000 km was selected to compare the results obtained by the software with those from literature. The tool not only obtained more results than the previous research, but the solutions found were also improved in terms of ΔV and time of flight. The second transfer was a GTO to lunar Gateway NRHO trajectory, which was chosen to show the applications of this study to problems of high scientific and industrial interest in present times, as well as to prove the versatility of the algorithm. Again, the results are better than the ones found in literature, if only by the number of different solutions that are obtained. Moreover, these results can easily be exported into a higherfidelity
software such as ASTOS.