Multiobjective trajectory optimization for a suborbital spaceplane using Directed Search Domain approach

The Directed Search Domain (DSD) technique is an efficient classical multiobjective optimization (MOO) method, which can generate a well-distributed Pareto set with a relatively low computational cost. In this research, DSD-III approach is applied to the multiobjective trajectory optimization for a suborbital spaceplane. Firstly, the flight profile is described and the objectives of three different missions are discussed. In each mission, the two-dimensional multiobjective optimization is proposed to search for the trade-off optimal solutions between the mission and vehicle design levels. Then, the dynamics and the suborbital spaceplane models are illustrated, and the optimization problems are formulated. Moreover, the main concepts and optimization theory of DSD-III algorithm are introduced. Finally, the numerical results are presented and analyzed. It is shown that the multiobjective trajectory optimizations can be effectively solved and the quasi-even Pareto sets are successfully obtained by DSD-III. In addition, some suggestions are given for the trade-off trajectory design.