Research on gravity-assist mechanism in circular restricted three-body problem

To the Gravity-Assist Technology in interplanetary mission, we research deeply on the relative between the independent variables that describe completely the Gravity-Assist maneuver and orbital change before and after gravity-assist maneuver by using Circular Restricted Three-body problem (CRTP). On the condition of CRTP, we provide the conditions of escape and captive, switching condition between direct orbit and retrograde orbit with gravity-assist maneuver in CRTP by using the method of forward and back integral. Taking the Earth-Moon system as an example, we provide the selection region of gravity-assist parameters that can achieve escape and captive and switch orbital type in Earth-Moon system with Moon gravity-assist. Finally, we analyze the influence of the latitude, velocity and phase angle of gravity-assist maneuver on change of orbital energy before and after gravity-assist in order to improve our understanding of this problem further.