Takeoff mass estimation methods in Two-Stage-To-Orbit RBCC-RKT launch vehicle

A method for estimating the takeoff mass of RBCC-RKT Two-Stage-To-Orbit (TSTO) horizontal takeoff launch vehicle was established to provide a reference for the scheme demonstration and preliminary design of TSTO vehicle Concept. The second stage takeoff mass was computed by conventional method for estimating multi-stage liquid-propellant rocket engine takeoff mass because vacuum specific impulse of liquid-propellant rocket engine was nearly invariable, while the first stage takeoff mass was optimized with the numerical integration for the motion equations of centroid by Augmented Lagrangian Genetic Algorithm because specific impulse of RBCC changed constantly with the flight condition. Possible factors influencing takeoff mass such as RBCC vehicle inert mass coefficient, maximum dynamic pressure, and aerodynamic characteristics were analyzed. The results show that the first stage takeoff mass will be reduced effectively by reducing RBCC vehicle inert mass ratio, increasing the first stage vehicle maximum dynamic pressure, or increasing the aircraft lift-drag ratio.