SABRE engine core

Combustion chamber of the SABRE engine core. The Synergistic Air-Breathing Rocket Engine, or SABRE, designed by UK-based Reaction Engines Ltd is a hybrid jet and rocket engine designed for a single-stage-to-orbit space plane. SABRE would use oxygen from the atmosphere until it reaches above Mach 5, after which it would shift to a closed-cycle rocket mode. The concept paves the way for true spaceplanes – lighter, reusable and able to fly from conventional runways.