Trajectory Design For Deep Space Exploration Mission

Deep space exploration is the most sophisticated engineering projectcurrently being investigated in all countries. The nation can demonstrate theirformidable technology and the pursuit to the unknown world. Trajectorydesign behind the launching of the spacecraft is important in the constructionof a basic mission profile. The paper mainly concerns on two types ofinterplanetary missions. One trajectory style is direct transfer from Earth toMars.The other style is multiplanetary exploration by using the technology ofmultiple gravity assist.Owing to the nonlinearity in the N-body problem and the big errorpropagation in the long flight time, the process to design the desiredinterplanetary reference trajectory is difficult. We develop a systematicmethod to solve this problem. We considered it as two point boundary valueproblem. The launch window is selected from porkchop plot obtained bycalculating Lambert problem. The injection position and the initial estimatevalue of the injection velocity required from parking orbit can be determinedby patched-conic approximation. The targeted orbit elements orbiting Marsare transformed into B-plane parameters, which are very nearly linearfunctions of the variables of the trajectory near the Earth.In particular,we alsodeduce the relation between B-plane parameters and orbit classical elementsin detail. The problem is solved by differential correction in which thesensitive matrix is acquired by numerical difference.The exploration of most of the solar system is beyond technicalpossibility if we don’t using the technology which is called multiple gravityassist. The research includes powered gravity assist and unpowered gravityassist. In this paper the preliminary design of multiple gravity assisttrajectories is formulated as a global optimization problem when thesequences of flyby planets are determined, by combining two kinds of gravityassist styles.The deep space maneuver(DSM) is applied after the unpowered gravity assist to adjust the trajectory of the spacecraft to accomplish the nextgravity assist with another planet.It is optimized using one kind of heuristicmethod which is referred as differential evolution.. We also develop the software interface named IMAT(InterplanetaryMission Analysis Tool) by VC++6.0to solve the two problems mentionedabove.We describe the software structure and the program flow in detail.Thesoftware settings and the configuration to use it are also presented. Severalillustrative examples are set out to show the software’s reliability andvalidity.