Reduction of the Pressurization System Final Mass for a Modern Rocket Launcher

The work focuses on optimizing the pressurization system’s operating performance for a fuel tank of a turbo-pumped liquid propellant rocket engine. This system is the most complex and expensive in a medium-size launch vehicle, after the engine. A new patented methodology of reducing the final mass of a rocket stage is proposed, studied, and validated. The application of the proposed method is efficient at the end of the engine operation sequence during the throttling regime. The calculation method of the helium excess in the high-pressure cylinders uses the model of the real gas. It also involves empirical relations describing nonstationary heat and mass transfer in the system. As an innovative technical solution, the authors propose to estimate excess gas discharge from tanks and cylinders after the engine’s last throttling. The practical application of the research allows saving tenths of kilograms of a payload with the implementation of simple modification in the launcher control program. The research results demonstrated the effectiveness of the methodology on the example of the RD-171 fuel tank pressurization system.