Multidisciplinary Design Optimization of Multi-Stage Launch Vehicle using Flight Phases Decomposition

Abstract

Optimal design of launch vehicles is a complex multidisciplinary problem. The traditional way to optimize such vehicles is to decompose the problem into the different disciplines and to combine specific solvers and a global optimizer. This paper presents a new MDO method to optimize the configuration of an expendable launch vehicle and describes the application of this method to the design optimization of a small liquid fueled multi-stage launch vehicle. The objective is the payload mass maximization. The proposed bi-level method splits up the original MDO problem into the flight phases and optimizes concurrently the different stages of the launch vehicle. This transversal decomposition allows to reduce the search domain at system-level because the optimization problem at this level is analog to a coordination one. Two formulations of the method are presented and the results are compared to the ones obtained by a standard MDO method.