Researchers and engineers active in the space industry operate not only with the aim of constantly improving the performance of the space vehicles, but they also strive to reduce the carbon footprint which has huge impact on the environment. Furthermore, the high level of quality should be guaranteed while keeping the total expenditure under control. A possible strategy that can be adopted to achieve the two previously mentioned objectives, reducing the carbon footprint and costs, is the transition from the expendable transportation systems to Reusable Launch Vehicles (RLVs). Nevertheless, the so far developed and fully operational RLVs are powered by bell nozzles which may not guarantee the best operating conditions neither during the ascent trajectory nor during the reentry maneuvers.