Impulsive lunar Halo transfers using the stable manifolds and lunar flybys

Since the stable manifolds of lunar Halo orbits could not approach the Earth, direct transfers from the Earth parking orbit to the stable manifolds is impossible. Three-impulse lunar Halo transfer using the stable manifolds and lunar flybys is studied in this paper. With an escape maneuver velocity about 3.1 km/s, the spacecraft departs from the Earth parking orbit. About 3–10 days later the spacecraft arrives at the vicinity of periselenium from where the spacecraft is injected into the stable manifolds of lunar Halo orbits with a second maneuver velocity about 180–220 m/s. After about 3–20 days, the spacecraft is captured into lunar Halo orbits with a third maneuver velocity about 0–160 m/s according to the size of the objective Halo orbit. The proposed transfer to lunar Halo orbit requires much lower maneuver velocity than that of direct fast transfer, and requires much shorter flight time than that of WSB transfer to lunar Halo orbit.