Multidisciplinary Design Analysis of Reusable European VTHL and VTVL Booster Stages

While initially met with skepticism, launch vehicles with reusable stages are now an established and successful part of the global launch market. Thus, there is a need to analyze and assess the possibility of such a system being designed and built in Europe. Accordingly, in 2016 the German Aerospace Center (DLR) initiated a study on reusable first stages named ENTRAIN (European Next Reusable Ariane). Within this study two return method categories, respectively vertical take-off, vertical landing (VTVL) and vertical take-off, horizontal landing (VTHL) with winged stages, were investigated. First, preliminary design tools were used to identify promising configurations and in the second phase more specialized and extensive analyses were conducted for subsystems of special interest. From this second phase, the results of the evaluation of two areas are presented: Structure as well as system dynamics, guidance and control. The results of these analyses together with previously published results from other subsystems increase the confidence in the designs proposed and evaluated within the ENTRAIN study as well as in the general understanding of the technical factors driving the design of reusable stages