Preliminary Design Global Optimization for Space Vehicles During Atmospheric Maneuvers

This paper proposes a multidisciplinary approach to the preliminary design of a space vehicle involved in atmospheric maneuvers: The shield shape, the bank angle profile, the entry conditions are defined according to an optimization procedure focused on the overall propelled ΔV minimization, the payload mass -protected by the shield- maximization, while maintaining several dynamic and boundary constraints satisfied. The problem is highly non-linear, and the local minima avoidance represents a great challenge for the multi-objective optimization. To cope the former issue, the stochastic techniques are here applied and the global Pareto front is caught As different disciplines are involved, several external tools are used for their modeling and connected to the main optimization core. The core is based on the EMOEA (Tan et al, 2003) enhanced with Elitism. Special attention has been paid in avoiding the genetic drift while maintaining the sparsity of the solutions both in the search and in the objective spaces. An architecture is here proposed to deal with the complex set of constraints coming from the control and configuration area. Simulations run on the selected application show the capability of the proposed approach to maintain the solutions within the feasibility region with a good sparsity level according to shape families and guidance histories, being a useful tool to suggest the analysts a reduced set of optimal solutions in terms of both guidance and shape features to be further refined. Simulations on Mars and Venus Aerocapture scenarios are reported and the results are critically discussed. Criteria to test the catching of the global Pareto front are presented for the applicative scenario.