Linking of Liquid Bipropellant Rocket Engine Design Methodology with Launch Vehicle Optimization

Abstract

The propulsion system is the single most important subsystem of a launch vehicle. Some of the characteristics of a vehicle can have a strong influence on the propulsion System requirements. In turn the vehicle requirements depend on the mission objectives. Therefore, the selection of optimal vehicle and propulsion designs for given flight applications have to combine both launch vehicle and propulsion optimization. The goal of the master thesis was to develop and implement an optimization Routine which is able to minimize the initial mass of a launch vehicle for a certain payload mass and target orbit by selecting the optimal staging of a rocket configuration and propulsion systems for the individual stages. For this purpose it was also necessary to study suitable mass estimates for the individual components of the launch vehicle. An integration of NASA CEA was used to calculate the rocket engine specific characteristics, e.g. specific impulse, for chosen propellant combinations and operating regimes. To find the optimal solution for certain constraints a genetic algorithm that is common in the field of multi-disciplinary design optimization was implemented. Several exemplary calculations demonstrate the usefulness of the work done.