Ahead of his participation in a FINN Sessions panel debate on future tech for engines at Farnborough Airshow next week, we caught up with Mark Thomas, CEO, Reaction Engines. He told us more about the work his company is doing in this area with its SABRE Engine.

What’s different about the SABRE engine?

At Reaction Engines, we are developing the next generation of engine technology which we believe has the potential to deliver transformationally lower launch costs.

SABRE – Synergetic Air Breathing Rocket Engine – is a new class of engine for propelling both high speed aircraft and spacecraft. They are unique in delivering the fuel efficiency of a jet engine with the power and high speed ability of a rocket.

SABRE’s highly efficient air-breathing design, which eliminates the need to carry on-board oxidiser during air-breathing flight segments, will enable aircraft-like horizontal take-off and landing operations, reducing cost, infrastructure and mission timelines, while increasing responsiveness and system reusability.

Central to the SABRE design is the breakthrough in aerospace engine technology we have achieved by developing ultra-lightweight heat exchangers (pre-cooler), which stop engine components overheating at high flight speeds. These are capable of cooling airstreams from over 1,000°C to -150°C in less than 1/20th of a second with world leading compactness and low weight.

How fast is an aircraft going to go with an engine like this?

The SABRE-class of engine is a unique proposition blending both jet engine and rocket technology and will facilitate the design of new classes of air and space launch vehicles. SABRE enables air-breathing flight from standstill to Mach 5+, before transitioning into rocket mode, allowing orbital access.

This means that SABRE-class engines are well suited for a variety of potential high-speed sub-orbital flight applications and ultimately, orbital launch systems.

SABRE-class engines will enable aircraft to fly over five times the speed of sound in the atmosphere and allow fully or partially reusable space launch vehicles to be built that will radically improve the affordability and responsiveness of access to space.

For example, SABRE powered vehicles will be capable of cutting the flight time from London to Australia to four and a half hours, or flying into orbit from a runway before returning to base and doing it all over again.

What other types of vehicles might a SABRE engine or its technology be used in?

In addition to being a key element of SABRE, the pre-cooler technology also finds application in conventional gas turbine jet engines. In particular, the pre-cooler can be used with current high-performance jet engines to extend the operational envelope of the engine, allowing faster speeds to be achieved as well as assisting in the thermal management of the engine, and may also enable more efficient next generation civil aero engines. We are working with a number of partners to explore these applications and understand how the technology may be applied to existing and future propulsion systems.

What stage are you at with testing the technology?

We now plan to take a prototype pre-cooler heat exchanger to a facility where we can undertake ground based tests that expose it to hypersonic conditions approaching1,000°C. This test programme, due to start later this year, is called the HTX Test Programme.

Reaction Engines Inc., our U.S. subsidiary, in collaboration with the U.S. Defense Advanced Research Projects Agency (DARPA) will conduct high-temperature airflow testing in the United States of the prototype pre-cooler test article. The primary HTX test objective is to validate pre-cooler performance under the high-temperature airflow conditions expected during high-speed flight, up to Mach 5.

This test will be one of the key stepping stones to a major project milestone that we aim to complete in the next few years. This will be the first ground based demonstration of a SABRE engine air-breathing core. This, together with the testing of critical subsystems will take place at an engine test facility that we recently began constructing at Westcott, some 25 miles from our Culham headquarters, and a site with a long heritage of rocket engine development in the UK.

What are the main things you have learned so far?

While the ultimate space launch application of the technology – and one where its greatest benefits will be derived – remains single-stage-to-orbit (SSTO) systems, we are seeing some interesting studies on potential two-stage-to-orbit (TSTO) architectures involving SABRE-class engines, which could be developed ahead of more technically challenging SSTO designs.

The use of a SABRE powered, fully reusable first stage enables the construction of a smaller, cheaper, expendable upper stage and gives the ability to recover around 90% of the launch system.

What’s next?

It is clear that we are currently in a period of significant innovation and rapid development in the space launch industry. Innovative new commercial entrants have significantly lowered the cost of space access, which has in turn opened up further commercial opportunities in space. As the industry develops and the demand for ultra-low cost access to space increases, we believe that there will be a need for the kind of revolutionary leap forward in propulsion that SABRE’s disruptive capability represents. The key elements of the SABRE class of engine have been validated in testing and we are about to enter a period where key development milestones will be met and the engine’s potential will start to be demonstrated.

What will the audience that comes to your session at Farnborough learn?

We will show the audience that what we are developing here is an entirely new class of aerospace engine, with the potential to revolutionise high speed flight and make orbital access as routine, safe and low cost as a flight across the Atlantic. SABRE is not just one engine, think of it as a class of engine in the same way as piston engines and gas turbines. We’ve designed SABRE to be modular and scalable, and this means we foresee the potential for a whole family of SABRE engines and a range of SABRE powered aerospace vehicles.

Of course we think SABRE will be a big part of the future of propulsion technology!

Find out more about the FINN Sessions.

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