Preliminary Design of Expendable and Reusable Mixed-staged Launch Vehicles

Abstract

One of the very first tasks in launch vehicle design is the preliminary sizing. It is necessary for further design choices, but should deliver as precise estimate of the launch vehicle's mass and geometry as possible. Orbital launch vehicles can be either expendable or partially/fully reusable, and can assume various stage configurations. Finding an optimal solution under practical constraints is a challenging task, which gives a wide design space for potential future launch vehicles. Hence, a generalized mathematical model of a launch vehicle design has been developed, and implemented as a versatile and easily modifiable programming tool for fast and parametric system characterization and optimization. The model uses several basic parameters useful in describing launch vehicles, and introduces some new parameters to account for reusability. Analytical and semi-empirical correlations are used to determine the overall system and mission performance of a launch vehicle for a given reference mission including mass and geometry and calculate the optimal launcher staging. The implementation of the model also allows coupling with other tools, which forms a design chain with respect to aerodynamics and trajectory simulation. With this design chain, several launch vehicles have been modeled and validated, proving the applicability of the method.