The Earth–Moon L1 libration point is proposed as a human gateway for space transportation system of the future. This paper
studies indirect transfer using the perturbed stable manifold and lunar flyby to the Earth–Moon L1 libration point. Although
traditional studies indicate that indirect transfer to the Earth–Moon L1 libration point does not save much fuel, this study
shows that energy efficient indirect transfer using the perturbed stable manifold and lunar flyby could be constructed in
an elegant way. The design process is given to construct indirect transfer to the Earth–Moon L1 libration point. Simulation
results show that indirect transfer to the Earth–Moon L1 libration point saves about 420 m/s maneuver velocity compared to
direct transfer, although the flight time is about 20 days longer.
Keywords Libration point - Transfer trajectory - Stable manifolds - Lunar flyby - Lunar exploration