Staging Optimization of Satellite Launch Vehicles: Application to a Microsatellite Launcher

Abstract

With modern technology, only a small percentage of the overall mass of a launch vehicle, usually less than 5%, can be used as payload mass. To achieve any acceptable performance, a key aspect that is exhaustively analyzed during vehicle design is the definition of the number and sizes of its stages. The problem of finding the best vehicle configuration for a given mission is called staging optimization. This work presents the formulation and a resolution method for the staging optimization of a launch vehicle. The problem is formulated as an optimal control problem (OCP) and, for its solution, a direct approach, employing a gradient-based algorithm as solver, is proposed. An application is performed for the Brazilian microsatellite launcher VLM-1. This vehicle has a notable characteristic that, in its nominal configuration, the first and second stages are very similar to each other (same solid rocket motor with the same quantity of propellant). Different vehicle configurations are investigated which result in an improvement in its performance. The obtained results show good agreement with those from a commercial optimization tool.