Conceptual design of a Two-Stage-To-Orbit vehicle using SABRE engines

The French Space Agency (Centre National d'Etudes Spatiales-CNES), the UK Space Agency (UKSA), Reaction Engines Limited (REL) and the French Aerospace Lab (Office National d'Etudes et de Recherches Aerospatiales-ONERA) share a common interest for future space launch architectures and technologies. Preliminary results of a joint study are presented in this paper with the main objective of assessing and quantifying the potential advantages and benefits of air-breathing propulsion technology developed by REL named SABRE (Synergetic Air-Breathing Rocket Engine) for future launch architectures. In that purpose, a conceptual study of two alternative Two-Stage-To-Orbit (TSTO) vehicles is carried out using the SABRE air-breathing rocket engine and a LOx/CH4 rocket engine (for the second stage) for the injection of a 15t payload into low Earth orbit. Different analyses are carried out using a coupled multidisciplinary process involving propulsion, aerodynamics, sizing and trajectory optimizations. Some key influential parameters and intricate behaviors are analyzed through sensitivity to the stage separation conditions. As a result, these analyses provide insight into technological requirements to achieve the target mission using these types of advanced propulsion technologies.