Design And Optimization Of Interplanetary Low Energy Transfer Trajectory

In the traditional orbit design of interplanetary transfer trajectory, the gravitation ofthe celestial bodies except the primary body is usually considered as the perturbativeforce. The additional energy is required to against the interference effect of theperturbative force. In recent years, the low energy transfer trajecorty which only existsunder the multi-body dynamic system has developed rapidly and attracted wideattention. The fuel consumption of the low energy transfer trajectory is lower than thatof the traditional two-body transfer trajectory, which is caused by the combined actionof the gravitation forces under the multi-body dynamic system. Employing lowenergy transfer can permit significantly lower velocity increments and/or largerpayload ratios. However, designing and optimizing low energy transfer trajectory is arather challenging task, for the complex dynamic environmental of multi-bodydynamic system and the long flying time.With the supports of State Key Program of National Natural Science of China‘Some Nonlinear Dynamics and Control Problems in Deep Space Exploration’ andNational Natural Science Foundation of China ‘Dynamics Mechanism, Design andOptimization Method Research for Deep Space Complex Sequence Micro-propulsionTrajectory’, this dissertation deeply studies the design and optimization methods ofinterplanetary low energy transfer trajectory. The main contents of this dissertation areas follows:The regions where low energy transfer exist are studied. Based on the dynamiccharacteristic, a technique is developed for estimating the value of the impulses usedin the low energy transfer. And the regions where the low energy transfer existsthough the comparison. To qualitatively investigate the velocity increment used in theinterplanetary transfer, the problem of transferring from a circular orbit around Earthto a target circular around Sun is structured. Four transfer strategies are investigatedand comparied, of which two ones are structured under two-body system and othersare structured under the restricted three-body system. For the low energy strategies, the methods to estimate the velocity increment are proposed with employing thepatched conic technique. Further, a systematic transfer trajectory design method isproposed. In the initial orbit design, the Poincare map and patched conic technique arecombined to calculate the significant parameters of the low energy transfer trajectory.In the optimization design, the orbit design under the four-body model is transferedinto a multi-parameter optimization problem which can be solved by the seqentialquadratic programming.The problem of designing the low energy transfer employing the invariantmanifolds and planetary gravity assist is studied. The feasibility of employing theperiodic orbit as the transfer station in the interplanetary transfer is analyzed, and thedesign method of the interplanetary transfers between periodic orbits of two differentthree-body systems is proposed. Firstly, the properties of the escape and capturetransfers are analyzed to definite which perodic orbit are more suitable for transferringto outer planet or inner planet. Then, a rapid initial design method is proposed byemploying the patched conic technique. In the initial design method, the periapsisPoincare map is used to analyze the periapsides of invariant manifolds, and theimpulses performed on the periapsis of invariant manifolds are calculated with asimple iterative algorithm on the basis of hyperbola approximation. Therefore, thetrajectory parameters can be obtained efficiently with maintaining the globaloptimality of the transfer trajectory. Further, a multistep optimization method isproposed to optimize the transfer trajectory under the ephemeris model. In theoptimization method, the trajectory is divided into several segments. For the manifoldsegements with strong nonlinearity, the multiple shooting method is employed. Forthe transfer between two periapsides which crosses several gravitational fields, theforward-backward integration is used for transfering the terminal state constraints intothe deep space. Therefore, the sensitivity of the constraints to the parameters isweakened and the convergence of the optimization problem is improved.The low energy interplanetary transfer trajectory with employing pseudo-manifoldis studied. Firstly, the pseudo-manifold with low stability coefficient is analyzed. Theconstruction and the flying time of the pseudo-manifold is complared with that of the invariant manifold. Then, a global initial searching method is proposed to find anappropriate transfer trajectory. In the searching method, the trajectory is divided intoseveral segments that can be designed under simple dynamical models, and ananalytical algorithm is developed for connecting the segments. The searching methodcan be used for a rapid global search of the transfer trajectories under the ephemerisconstraints and provide a set of initial fast low-energy transfers. Finnally, themulti-objective optimization model of the low energy transfer trajectory is structuredto resolve the conflict between the flying time and fuel consumption. In themulti-objective optimization, splitting method is used for the rapid calculation of theperiapsides of the pseudo-manifolds. Therefore, the inegration process is avoided sothat the solutions can be obtained quickly and efficiently.Combining the study contents of this dissertation above, the low energy transfertrajectories for Manned asteroid exploration are computated and analyzed in detail.Firstly, the mission constraints are analyzed in detail based on the characteristics ofthe Manned asteroid exploration, the screening strategy which gives considerationengineering practical and scientific value of the traget asteroid is proposed. Then,several track scheme of Manned asteroid exploration are proposed and compared, andthe low energy transfer scheme is determined. Further, the choice problem of theparking orbit for the cargo spaceship is analyzed. Finnally, the practicability of theproposed low energy transfer strategy and the availability of the orbit design methodis verified by desiging and analyzing the low energy transfer trajectories for Mannedasteroid exploration.