Trajectory Optimization and Performances of RBCC for Long-Range Return Missions of Reusable Vehicle

This study analyzes the performance of a Rocket-Based Combined Cycle (RBCC) engine for a reentry vehicle's long-range return mission using trajectory optimization.Using OpenGoddard, maximum-range trajectories were derived and compared for an X-37B based vehicle equipped with either an RBCC engine or a conventional liquid rocket engine.The analysis revealed that the RBCC engine's performance varied significantly with maximum thrust.Under a low-thrust condition (1 kN), the flight range increased by only 1.13% compared to the rocket, whereas a high-thrust condition (29.4 kN) resulted in a significant 42.91% increase.This is because sufficient thrust enabled an optimal maneuver that first utilized the high-efficiency ramjet mode and subsequently climbed to a high-altitude, low-drag regime.Therefore, securing sufficient thrust is a key design condition for the effective application of an RBCC engine to the long-range missions of reentry vehicles. (RBCC) .OpenGoddard X-37B RBCC . , RBCC .(1 kN) 1.13% , (29.4kN) 42.