AIAA SciTech Forum 2025

Abstract

Optimising a vehicle's design and trajectory simultaneously to maximise a mission objective, which we term co-design, may be particularly suited to hypersonic vehicles. Trajectories of these vehicles cover a wide flight envelope and will likely have influential thermal, dynamic pressure, and stability constraints. The lack of established reference vehicles and the lack of obvious nominal operating points at which to optimise a vehicle's design can complicate traditional methods in which separate tools are used for aerodynamic design, thermal protection design, and trajectory planning. Conversely, directly modelling the influence of each design parameter on an overall mission objective provides a simplified and systematic method to reach high-performing designs with potentially fewer design iterations. This paper describes the continued work of the authors to develop a computationally tractable co-design framework suitable for use with high-fidelity computational fluid dynamics. Additional design parameters impose very low marginal computational cost, which permits vehicle designs with many degrees of freedom. The method is demonstrated by finding the optimal design of two vehicles subject to geometric, internal volume, and static stability constraints. Each vehicle is designed for an optimum three degree-of-freedom trajectory subject to different trajectory constraints, resulting in two distinct vehicle designs. We demonstrate the superior performance of a vehicle executing its co-designed trajectory compared to the optimal trajectory of a second vehicle subject to its non-designed constraints, in turn highlighting the utility of the co-design method. Moreover, the framework is well-suited to incorporate thermal constraints and propulsion models in future work. Moreover, replacing the current approximate aerodynamic model with high-fidelity computational fluid dynamics, and incorporating thermal constraints and propulsion models, will likely further differentiate vehicles designed for specific missions