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UK to invest £60 million in air-breathing rocket engine

Jenny Winder, News Writer
Jul 19, 2013, 7:00 UTC

Sen—The UK Government, through the UK Space Agency, is to invest £60 million in the development of the world's first prototype Synergistic Air-Breathing Rocket Engine, or SABRE.

Designed by UK company Reaction Engines Ltd, this unique engine will use atmospheric air in the early part of the flight before switching to rocket mode for the final ascent to orbit. This could revolutionise the fields of propulsion and launcher technology, paving the way for lighter, reusable, spaceplanes, able to fly from conventional runways, significantly reducing the costs of accessing space.

Reaction Engines plans for SABRE to power the 84 m-long, reusable and pilotless spaceplane called Skylon, which would do the same job as today’s rockets while operating like an aeroplane.

The project, which has already successfully passed a UK Space Agency technical assessment, would be capable of delivering payloads of up to 15 tonnes into Low Earth Orbit at about 1/50th of the cost of traditional expendable launch vehicles, such as rockets.

The investment decision followed the success of European Space Agency review a key element of the SABRE design, a precooler to chill the hot air entering the engine at hypersonic speed, in Reaction Engines' Oxfordshire headquarters back in November 2012.

Precooler testing for SABRE engine. Image credit: Reaction Engines Ltd.

"Ambient air comes in and is cooled down to below freezing in a fraction of a second," explained Mark Ford, head of ESA’s propulsion section. "These types of heat exchangers exist in the real world but they’re the size of a factory.

"The key part of this is that Reaction Engines has produced something sufficiently light and compact that it can be flown.

"The idea behind the engine is that the vehicle flies to about Mach 5 in the lower atmosphere using airbreathing before it switches internal liquid oxygen for the rest of its flight to orbit.

"At that speed, the air is coming in extremely fast. You need to slow it down in order to burn it in the engine, and doing so will raise the temperature of the air to about a thousand degrees, which can exceed engine material temperature limits.

"Hence the concept of the precooler is to cool the air down to a temperature that is then usable by the engine.

The idea has been around since the 1950s but this is the first time anyone has managed to achieve a working system. Nobody else has this technology, so Europe has a real technological lead here."

Cutaway of the SABRE engine, with notes. Image credit: Reaction Engines Ltd.

The £60 million invested by Government will help to prime the pump for the remainder of the investment capital needed for full engine development. It will be staged over two years, £35m in 2014/2015 and £25m in 2015/2016.

UK Science Minister David Willetts, said, "By supporting this breakthrough technology we are giving the UK a leading position in a growing market of new generation launchers and removing one of the main barriers to the growth of commercial activity in space."

Alan Bond, who founded Reaction Engines and has led the research for over 30 years, added, "This significant investment in British high-tech technology is a fantastic shot in the arm for the UK aerospace and space sectors, as well as the broader economy."

A prototype SABRE is expected by 2017, and flight tests for the engine around 2020.