Study On Orbits Of Manned Lunar Mission Supported By Space Station On L2 Point

Manned lunar mission is a hot spot in the field of international manned space flight.In this paper,the orbital problems in the manned lunar mission based on the space station parking on Halo orbit near the Earth-Moon L2 libration point,are studied.The main contents are as follows:For the long-term parking mission of LL2 point space station,the design method of Halo orbit under the high-precision model is proposed.The transformation between the synodical coordinate frame defined in CR3 BP and J2000 coordinate frame defined in high-precision model,is derived detailedly.Based on this transformation,the initial value of Halo orbit under the high-precision model is obtained.The sequence quadratic programming algorithm is used to correct the initial values layer by layer,and the Halo orbit under high-precision model is obtained.For the mission of cargo transportation from low Earth orbits(LEOs)to LL2 point space station,an indirect transfer orbit design method based on the invariant manifolds and lunar flyby is proposed.In order to reduce the cargo transportation cost,taking into account the fuel economy of invariant manifolds and lunar flyby,an indirect transfer method based on invariant manifolds and lunar flyby is proposed.And a calculation model based on CR3 BP for LEO-(LL2)Halo indirect transfer trajectories is established,and the orbital fuel consumption characteristics are analyzed.For the mission of personnel transportation from LEOs to LL2 point space station,a design method for the direct transfer trajectories from LEOs to LL2 point Halo orbits is proposed.In order to shorten the transfer time of personnel transportation,And a calculation model based on CR3 BP for LEO-(LL2)Halo direct transfer trajectories is established.Based on the CR3 BP model,a monthly window calculation model is established by coordinate transformation,and the variation rule of moon windows of LEO-(LL2)Halo direct transfer trajectories are analyzed.Taking into account the launch site constraint,a calculation model based on high-precision model for LEO-(LL2)Halo direct transfer trajectories is established.For the manned lunar mission from the LL2 point space station,a design method for the direct transfer trajectories from LL2 point Halo orbits to low lunar orbits(LLOs)is proposed.In order to shorten the transfer time of personnel transportation,a direct transfer scheme is proposed.And a calculation model based on CR3 BP for(LL2)Halo-LLO direct transfer trajectories is established.A lunar orbit lunar reachable area calculation model through the coordinate transformation is designed,and the property of lunar reachable area of(LL2)Halo-LLO direct transfer trajectories is analyzed.Considering the landing point constraint,a calculation model based on high-precision model for(LL2)Halo-LLO direct transfer trajectories is established.The dissertation focuses on the specific tasks of manned lunar mission supported by LL2 point space station and proposes some orbit design methods including design of Halo orbit under the high precision model,design of low energy and rapid transfer trajectories from LEO to LL2 point Halo orbit and design of rapid transfer trajectories from LL2 point Halo orbit to LLO.The research results can provide an effective orbit design tool for the manned lunar mission supported by the libration point space station.