Hypersonic Vehicle Co-Design for Multi-Stage Mission Planning

Optimization of a vehicle's physical design and flight trajectory in the same procedure is a process commonly known as co-design. The co-design framework is particularly suited to hypersonic vehicle design, since it has the potential to greatly reduce the number of development cycle iterations. Recent progress has led to co-design in models of increasing complexity, with higher fidelity achieved in the vehicle parameterization, physical models used in the dynamical systems governing the underlying optimal control problem, as well as the surrogate functions used in estimation of the aerodynamic forces. However, these works have so far only considered vehicle designs optimized for a single part of a mission, namely a boost or glide stage. While performance for multiple mission objectives within a single stage mission has also been considered, realistic missions are more complex and consist of multiple stages, requiring incorporation of launch, boost, and glide phases. Since a vehicle optimized for any single one of these may perform poorly or even not survive the flight conditions necessary for another stage, it is imperative to design vehicles with their entire life cycle in mind. In this work we extend the previous co-design frameworks to incorporate multiple mission stages, and demonstrate on a number of test cases.