Founded 35 years ago by Alan Bond, the lead engineer on the British Interplanetary Society's Project Daedalus and the designer of British Aerospace's HOTOL single-stage-to-orbit spaceplane, and chaired by Philip Dunne, a former defense minister, Reaction Engines focused on developing advanced space propulsion systems. Its primary goal was to one day build the company's Skylon spaceplane, though it also farmed out its key technologies to other projects and conducted tests for customers, including the US Air Force.