. "HOTOL, for Horizontal Take-Off and Landing, was a British design for an Airbreathing jet engine spaceplane by Rolls-Royce and British Aerospace.Designed as a single-stage-to-orbit (SSTO) reusable winged launch vehicle, it was to be fitted with a unique air-breathing engine, the RB545 or Swallow, to be developed by the Rolls-Royce company."@en . .