Optimization of Hybrid Sounding Rockets for Hypersonic Testing

The use of ground-launched hybrid rockets to bring subscale models to flight conditions within the hypersonic flight corridor is investigated. The analysis is based on a multidisciplinary optimization procedure that couples the direct optimizations of the parameters that rule the engine geometry and operation and the indirect optimization of the trajectory. The final Mach number is maximized for given initial conditions and assigned payload and final altitude. Different rocket configurations are considered; in particular, the performances of single stage and two stage rockets are determined for different payload fractions. Results show that hybrid motors are suitable to accomplish this kind of mission and that single stage rockets are preferable. Only when the payload fraction is very small and large final velocities are sought, two stage rockets may offer better performance.