Target Sequence Design And Trajectory Optimization Of Multi-objection For Asteroid Exploration

With the development of deep space exploration technology,people have succeeded to complete the exploration task for eight major planets.Therefore,more and more countries start to devote their efforts on deep space exploration to asteroid exploration.The difficulties in recent time are how to save time and costs when complete those missions.Besides,it is also a new challenge for multiple targets of mission costs detection.For deep space exploration,the orbit design needs to be considered first.The reasonable orbit design can not only reduce the fuel consumption,but also effectively shorten the task time.Hence,in this paper,the multi-objective orbit design under pulse transfer and low thrust transfer are studied.First,the objective selection problem of multi-objective detection is analyzed.We select the earth Trojan asteroid 2010TK7 as the main detection target,and draw the energy contour map of the Earth-210TK7 asteroid to get the approximate launch time window.In order to improve the computational efficiency,the genetic algorithm is applied to eptimize the best launch time.To reduce the fuel consumption,multi-pulse orbit has been designed to reduce the speed increments.Secondly,three gravity-assist methods are compared: power-free gravity assist,impulsive gravity assist and the gravity assist combined with deep space maneuver.We impove the method for solving parameters in gravity assist,effectively reduce the difficulty of design,and make it more suitable for the orbit design of multi times gravity assist.Further,when considering the flight time and fuel consumption,two sets of multi-objective orbit design schemes with 2010TK7 as the main detection target are given.The correctness of the multi-objective orbit design ideas and the gravity assist approaches are verified.Finally,the two-dimensional and three-dimensional low-thrust trajectory design of Apophis and 2010TK7 asteroids were carried out by using sinusoidal method and inverse six-order polynomial curve approximation method respectively.In the mean time,the orbits of small thrust levitation and multi-target detection have also been designed.Moreever,we analyze and expand the situation where the feasible solutrens to the flight time equation are lost and hence,the range of feasinle solutions are increased.