Investigation On Low-energy Escaping And Capturing Trajectories For Deep Space Exploration Mission

The libration point orbits and their invariant manifolds structure of three-body systemare applied widely in recent deep space exploration missions. The Sun-Earth(SE)/Earth-Moon (EM) system L1/L2is suggested as the primary hub for future humanspace activities; the design of low-energy capture trajectory is feasible in the Sun-Planetsystem. For the interplanetary transfer trajectory, both of the escape and capture trajectoriesshould take into account the multi-body system if the low energy is desired. Thus, thedynamic characteristics and design method in three-body/four-body system for escape andcapture trajectories are the key points in the low-energy interplanetary trajectory. Theresearch works in this thesis are stated as follows:For the escape trajectory in three-body system, two types of escape, direct and indirectescape, are studied. First, on the basis of Planar Circular Restricted Three-body model, therelationship between escaping maneuver and Earth hyperbolic excess velocityVE isconstructed, and the universal conclusion is obtained. Then, the methods for designingdirect escape and indirect escaping trajectories are proposed on the basis of ephemeristhree-body systems and conic patching programme. Finally, a step-by-step analyticalmethod for design of direct escape trajectory is derived.For the escape trajectory in four-body system, the inner escape and outer escape arestudied. For the inner escape trajectory, a method for designing single-impulse transfertrajectory is proposed based on the Poincare Map of movements around the libration point.Taking the transfer from the Moon to SE libration point in Sun-Earth-Moon system, thedistribution of transfer opportunities, relation between escaping maneuver and amplitudesof libration point orbits, and the classification of libration point orbits, are analyzed. For theouter escape trajectory, the feasibility of indirect escaping trajectory for Moon-asteroidtramsfer is analyzed by calculating all of the low-energy Moon-Earth transfers. Theperigee-maneuver escape trajectories are calculated and some scenarios, escaping maneuverare far less than that of three-body escaping, are obtained.For the capture trajectory in three-body system, a two-impulse ballistic capture trajectory is proposed based on the invariant manifold construction in three-body system.This method is effective to overcome difficult problem that the periapsis height of twokinds of stable manifolds do not meet the capturing constraints for the design of capturetrajectory using manifolds. The relationship between ballasitc trajectory and JacobiConstant of system is built to search the capture opportunities. A one-dimensional searchprocedure can calculate the combined capture trajectory. This study expands the low-energycapture opportunities into Mars halo orbit.The application of low-energy escape and capture trajectories in libration pointmission is investigated systemetically. First, the trajectory reconstructive method for thetransfer from the Moon to SE libratiion point is proposed based on the inner traectroy offour-body system. The investigation indicates that the choice of transfer opportunity shouldconsider both the escaping maneuver and reconstructive maneuver. Then, for the optimalimpulse transfer from SE libration point to asteroid, the perturbation method and primervector theory are used to design the initial trajectories and optimal impulse ones,respectively. Two transfer families, slow and fast transfers, are found.The application of low-energy escape and capture trajectories in interplanetary transferis investigated systematically. A two-level search procedure is proposed based on theinvariant manifolds struction of three-body. In the method, the first-level search procedureis performed under the conditions of the initial time of escape manifold and the terminaltime of capture manifold fixed, by solving the optimal two-impulsive heliocentric trajectoryto connect the two manifolds. The contour map, helpful to the understanding of the globalcharacteristics of transfer opportunities, taking the initial and terminal time as variables, thefirst-level optimal velocity invrement as objective function, is used for the second-levelsearch. The results indicate that the transfer opportunities for Earth-Mars and Earth-Venusare quasi-periodic.