Space Launcher Design with Thrust Profile and Trajectory Optimization

Design of a space launch vehicle is a very challenging and long running activity because of highly complex and interconnected nature of the launch vehicles. In the frame of this study, it was aimed to develop a quick and effective tool to find optimal vehicle configurations in the early design phases. First, a trajectory optimization code utilizing a general purpose optimal control solver GPOPS-II® was developed to determine the optimal trajectory in terms of position and velocity, and the control functions corresponding to that trajectory while maximizing the payload mass. Next, a staging optimization code was developed to determine the staging parameters (number of stages, mass distribution between stages, and the propellant and structural mass of each individual stage) which minimize the gross lift-off mass. Finally, these two codes were integrated for simultaneous optimization of the thrust and mass profile of the stages together with the trajectory of the launch vehicle. This newly developed tool can be utilized both for preliminary mission design of an existing launch vehicle and conceptual design of a new launch vehicle.