ESA Funding Boosts Development of SABRE Spaceplane

It's about time that rockets had a revolution in design. While Orbital ATK and NASA are working on putting people outside of cislunar space and eventually bringing them to Mars, the UK's Reaction Engines Ltd. has been developing a prototype rocket engine that can fly from the Earth to low orbit and back on a single stage.

Enter SABRE

A cutaway of the SABRE engine's nacelle. (Image courtesy of Reaction Engines Ltd.)

The European Space Agency (ESA) and the UK government have been funding the SABRE program since last year. The UK Space Agency has already invested £50 million and this latest €10 million investment contract from the ESA marks the final agreed-upon contribution.

Mark Thomas, CEO of Reaction Engines Ltd., said, “We've had valuable support from ESA and UKSA to date, and today's agreement is a further vote of confidence not only in the revolutionary potential of this technology, but our ability to deliver on it. We are now entering an exciting phase where we can accelerate the pace of development to get SABRE up and running.”

The SABRE is unique in that is has two distinct rocket modes of operation.

Air breathing mode—The engine sucks in atmospheric air as a source of oxygen (as in a typical jet engine) to burn with its liquid hydrogen fuel in the rocket combustion chamber.
Conventional rocket mode—The engine is above the atmosphere and transitions to using conventional onboard liquid oxygen.

This is made possible by a revolutionary heat exchange system within the engine. As the air enters the engine at extremely high temperatures, it passes through a system of tubes containing high pressure helium. This drops the temperature to more manageable levels in as little as 20 milliseconds.

A simplified diagram of SABRE's cycle. (Image courtesy of Reaction Engines Ltd.)

This allows the engine to operate at higher speeds than traditional jet engines, which is necessary if you want to get into orbit. It also reduces the amount of oxygen that needs to be carried on the plane, greatly reducing the vehicle’s weight. A potentially more impactful use of the engine is with in-atmosphere flight, where the engine could make a trip from London to Sydney in about four hours. This is a massive difference from the current 20+ hours needed for the trip, which includes a stopover.

The SABRE is being developed with Reaction Engine's SKYLON spaceplane in mind, which would place it as one of few vehicles currently in development for regular trips to space. An unpiloted, reusable spaceplane capable of moving upward of 15 tons of cargo between the Earth and space could definitely be useful. The SKYLON is still in early development, but with the backing of the ESA, it could become a reality as early as 2020.

To find out more on the ESA's funding program for SABRE or SKYLON, visit their respective websites.