Reaction Engines Limited promises to take you anywhere in the world within a time span of only four hours, which would seem impossible today through any mode of transportation. Reaction engines however challenge to do the same and have already successfully completed testing of their newly designed propulsion system, which can make it possible in the near future.
The initiative behind the Reaction Engines Limited system is similar to what we now see with current jetliners, but would function as a rocket. They name the system as SABRE, it burns hydrogen and oxygen but the system utilizes oxygen from atmosphere, similar to that of jet engine.
The propulsion system would be fixed with a 275-feet long Skylon Spaceplane, Taking off and landing rules are similar to those of a regular airbus. The vehicle once reaches its speed of about Mach 5 tends to utilize its onboard fuel supply. Because the engine gathers its oxygen supply from the air for take-off, a higher thrust-to-weight ratio is achieved in the absence of on-board fuel. The company still is in need of approximately 400 million USD; the company is trying to seek the following investment from private investors and is confident enough that they will continue to come in as the project continues over the next four years.