A Multidisciplinary Variable-Fidelity Framework for the Design of Launch Vehicles

In recent years, the pursuit of higher affordability in access to space has led to a paradigm shift in the field of launch vehicle design. In particular, to significantly reduce the cost and speed up the conceptual design phase, designers often adopt a multidisciplinary workflow. This paper aims to present a methodology for the design of launch vehicles that exploits both high-fidelity and reduced-order model tools. Focusing on the design of a medium launch vehicle in terms of payload and target mission, first, a preliminary sizing phase is performed, defining a first guess for the mass and geometry. Then, employing simplified drag coefficient calculations, the trajectory of the launch vehicle is computed. Afterwards, high-fidelity Computational Fluid Dynamics (CFD) simulations are used to calculate the aerodynamic properties of the vehicle, and the static stability of the vehicle is verified under the most critical flight phase. Those detailed aerodynamic properties are then used for the optimization of the vehicle trajectory, shape, and control, thus obtaining a reliable mission profile for a fraction of the computational burden. This procedure is repeated until convergence is achieved on the geometry of the \gls{lv}. Finally, the dynamic stability of the vehicle is verified by studying the control system. This workflow allows for leveraging both the affordability of analytical tools and the reliability of high-fidelity simulations to provide a solid design at a low overall cost.