**5. Designing hypersonic vehicles and preset book aims**

Such a limited number of operating HVs are due to the high operative cost and, especially, to the complexity in designing such vehicles, especially for human-rated missions. Indeed, HVs' design is an extremely challenging process involving several disciplines, e.g., aerodynamic, aerothermodynamic, control, avionics navigation systems, propulsion, and structure. As well known, these disciplines are strongly coupled with one another and generally influence each other because they involve antagonistic objectives. Therefore, it is expected that synergistic interactions, between vehicle subsystems and functions, can produce an optimized multidisciplinary vehicle design with significant performance and economic improvements [32–40].

This suggests using specific methodologies to assess trade-off analyses between the enabling disciplines as the only way to obtain a satisfactory (global optimal) vehicle design, referred to as multidisciplinary design optimization (MDO) [41–48].

The book aims at highlighting that the design of HVs must pass from a conventional design to a more complex and challenging highly integrated design framework, according to the MDO approach.

Several chapters in the present book focused attention on this fundamental topic, especially for what concerns the design of scramjet-propelled vehicle configurations. For instance, the design and optimization about the integration of airframe-propulsion design issue are discussed as well as the design of vehicle TPS with parametric integral soft object-based procedure. Anyway, investigations of more conventional topics are also provided in the book, as numerical simulations of base pressure and drag of typical reentry vehicles.

In this framework, the ambition of the present book is to support industries, research centers, and space agencies in their own design and development of next-generation HVs. Therefore, this book is recommended for both students and research engineers involved in all design phases, typical for hypersonic vehicles.

*Hypersonic Vehicles - Past, Present and Future Developments*
