Skylon Spaceplane: United Kingdom’s Reusable Rocket

Developed from HOTOL (Horizontal Take-Off and Landing) project Skylon is a series of designs for a single-stage-to-orbit spaceplane by the British company Reaction Engines Limited (REL), using SABRE, a combined-cycle, air-breathing rocket propulsion system. The vehicle design is for a hydrogen-fuelled aircraft that would take off from a purpose-built runway, and accelerate to Mach 5.4 at 26 kilometres (16 mi) altitude (compared to typical airliners’ 9–13 kilometres (6–8 mi)) using the atmosphere’s oxygen be