Multi-phase trajectory optimization for access-to-space with RBCC-powered TSTO via surrogated-assisted hybrid evolutionary algorithms incorporating pseudo-spectral methods

A multi-objective design optimization study coupling evolutionary algorithms and trajectory optimization via pseudo-spectral methods has been conducted for two-stage to orbit (TSTO) system with a rocket-based combined cycle (RBCC) comprising airbreathing components besides rocket engines, aiming to examine its feasibility to achieve efficient access to space, particularly to the international space station. The optimization has been performed with respect to three important design criteria, that is, the maximization of the final velocity, altitude, and mass at the terminus of the orbiter trajectory under certain constraints of acceleration and dynamic pressure. The results have revealed complex interactions of numerous design parameters and a counteractive trend between the final velocity and mass. Most influential parameters have been identified from trajectory investigation and sensitivity analysis, providing insights into the design requirements needed to fulfill the desired mission with the vehicle and propulsion configurations considered here.