Launch vehicle multibody dynamics modeling framework for preliminary design studies

Launch vehicle dynamics modeling is quite challenging mainly because of the highly interconnected disciplines involved: propulsion, aerodynamics, structures, mechanisms, and GNC among others. Discipline experts perform their respective design often independently and with separate dedicated tools. Consequently, during launcher preliminary design studies, numerous iterations are required in order to keep mission objectives synchronized. These preliminary design efforts can potentially be reduced by using a multidisciplinary launch vehicle model integrated in one single tool. Because this allows to reduce the number of iterations and the associated costs, a launch vehicle multibody dynamics modeling framework is a key technology to aim for. Dedicated developments of multidisciplinary modeling tools for launch vehicle multibody dynamics have been presented in the relevant literature. However, none fully profits from an object-oriented, equation-based, and acausal modeling language like Modelica. As yet, such an approach is still missing. It is therefore the objective of this paper to introduce such an alternative approach employing this modeling framework. This framework enables object-oriented and physics-based modeling of subsystems and components related to most key analyses of a launcher system. These include among others: launcher configuration, staging and separation dynamics, end-to-end trajectories, performance, controllability and stability. Moreover, all this can be done within a single simulation environment. The paper gives an overview on the first building blocks leading to an integrated and multidisciplinary tool for launcher preliminary design studies. Particularly, its easiness of implementation is demonstrated along with the benefits of this approach