Reaction Engines Skylon

The Skylon vehicle is an aircraft designed to reach orbit.

In aerospace, Skylon is a design by Reaction Engines Limited (managed by British rocket scientist Alan Bond) for an airbreathing single-stage to orbit, precooled air turborocket based spaceplane. A fleet of vehicles is envisaged; each vehicle would be reusable at least 200 times. Costs per kilogram of payload would be below the current costs of launch (as of 2006), including the costs of R&D, with costs expected to fall much more over time after the initial expenditures have amortised. The cost of the program, including production of a small fleet of aircraft has been estimated to be about $10 billion.

The vehicle would be a hydrogen-powered aircraft that would take off from a conventional runway, and accelerate to Mach 5.5 at 26 km before switching the rocket engine to internal LOX supply to take it to orbit. It would then release a 12-tonne payload, and reenter. The payload would be carried in a standard payload container.

During reentry the relatively light vehicle would fly back through the atmosphere and land back at the runway, with its skin protected by a strong ceramic. The vehicle would then undergo any necessary maintenance and would be able to fly again within 2 days.

The proposed engine for the vehicle is not a scramjet, but a precooled jet engine. Originally the key technology for this did not exist - the required heat exchanger was about ten times lighter than the state of the art. However, research has now achieved the necessary performance. Currently no funding to fully develop and build the vehicle exists, but research and development work is nevertheless ongoing, particularly on the engine.

Source: Wikipedia