spaceSpace and Physics

Space Plane Company Develops Revolutionary Hybrid Rocket Engine That Could Take You Anywhere In The World In Four Hours


Jonathan O'Callaghan

Senior Staff Writer

3396 Space Plane Company Develops Revolutionary Hybrid Rocket Engine That Could Take You Anywhere In The World In Four Hours
Skylon could take passengers and cargo into orbit. Reaction Engines.

British company Reaction Engines Limited (REL), which is developing an engine that could be used on space planes in the future, has received a significant amount of funding from aerospace company BAE Systems. The £20.6 million ($31.7 million) investment, which accounts for a 20 percent stake in the company, will be used to develop the engine, with REL also planning their own space plane known as Skylon.

The engine, called SABRE (Synergistic Air-Breathing Rocket Engine), has been in development in one form or another by Oxford-based REL since 1989. Although it has yet to be completed, the company is pushing toward a full ground test in 2020. 


It is a hybrid jet/rocket engine that allows a vehicle to operate both within the atmosphere of Earth and outside, in space. No other engine of its kind has been flown before, and in recent years it has gained considerable publicity owing to the possibilities of spaceflight it could usher in.

“Today’s announcement represents an important landmark in the transition of Reaction Engines from a company that has been focused on the research and testing of enabling technologies for the SABRE engine to one that is now focused on the development and testing of the world’s first SABRE engine,” Mark Thomas, Managing Director of REL, said in a statement.

The cash injection follows an investment of £60 million ($92 million) from the U.K. government. The SABRE engine has been heralded as a breakthrough in British engineering not too dissimilar to the ill-fated Concorde. On this occasion, however, it is the engine itself and not the entire vehicle that is of interest, and it could be used in a wide variety of vehicles.

SABRE can operate both on Earth and in space. Docubyte/Reaction Engines Limited.


In the skies of Earth, SABRE operates in an air-breathing jet mode, sucking in atmospheric air and burning oxygen with liquid hydrogen fuel in its combustion chamber. When in the vacuum of space, however, the engine switches to using on-board liquid oxygen to provide a huge amount of thrust.

The key breakthrough in the engine, and a feature that was kept firmly under wraps until recently, is how it copes with frost. The engine chills incoming air from over 1,000°C (1,800°F) to -150°C (-240°F) in less than 0.01 seconds, and in July this year it was revealed that a methanol injection is used to function as antifreeze.

REL has designs on one day using its SABRE engine on its own Skylon space plane. This futuristic vehicle, which remains very much just a concept for now, would be capable of taking off from and landing on many conventional runways on Earth – with a bit of reinforcement. Skylon would be used to ferry passengers and cargo to sub-orbit, or even full orbit, depending on how far the concept can go. Some even view it as the future of the fledgling space tourism industry.

Compared to other space tourism endeavours such as Virgin Galactic’s SpaceShipTwo, Blue Origin’s New Shepherd, or even SpaceX’s Dragon capsule, Skylon does not require either a “mothership” to take it into the sky like the former, or a vertical rocket launch like the latter two. For this reason it is a very attractive proposition.


For now, though, the focus is very much on the SABRE engine. The company is hoping to have their ground-based test engine working by the end of the decade, with unmanned test flights beginning in 2025.

“This investment by BAE Systems reflects the strength of British engineering and technology and our ambitions as a leading space nation,” said MP Jo Johnson, Minister for Universities and Science in the UK in the statement. “I am sure that this partnership will strengthen both organisations – helping to create more jobs in the UK’s growing space sector and ultimately to make the SABRE engine a reality.”


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