Sabre: The Little Engine That Could


Skylon Sabre-Powered Space Plane

Artists Impression of Skylon Sabre-Powered Space Plane in Orbit, courtesy Reaction Engines Ltd

What if rockets didn’t require those heavy oxidizers to get into orbit? Three years ago, the European Space Agency (ESA), in daring to dream, awarded a €1 million grant to a British firm that was looking into air-breathing spacecraft.

That grant, from the ESA, was to British company Reaction Engines Limited (REL) whose aim was to create a space plane that can take off and land like a conventional plane, yet still achieve orbit, by mixing air-breathing jets for take-off and landing with rockets (fueled by onboard oxygen) past a certain speed.

This is known as the British Skylon space plane — a reusable launch vehicle that will be powered by a two-in-one air-breathing rocket engine that can boost the plane to Mach 5.5 and a height of nearly 30 km (18 miles). The latest news is that the theoretic Sabre Engine isn’t so theoretic anymore; it passed a critical heat tolerance and cooling test — which will now pave the way for Skylon to move from concept to reality.

Because of the successful test, REL won an important endorsement from the ESA. Speaking at a press conference on November 28th, ESA’s Mark Ford had this to say:

ESA are satisfied that the tests demonstrate the technology required for the Sabre engine development. One of the major obstacles to a reusable vehicle has been removed. The gateway is now open to move beyond the jet age.

And indeed, this really is big news. As Skymania‘s Paul Sutherland noted, it’s “the biggest breakthrough in flight technology since the invention of the jet engine.”

The Sabre engine was the crucial piece in the reusable space plane puzzle.

Above: Skylon Sabre Heatex from REL

The recent breakthrough had to do to with the development of a heat exchanger that’s able to cool air sucked into the engine at high speed from 1,000 degrees Celsius to minus 150 degrees in one hundredth of a second. It’s this critical technology that will allow the Sabre engine to surpass the bounds of a traditional jet engine — by as much as twofold.

Chris Wickham explains:

With the Sabre engine in jet mode, the air has to be compressed before being injected into the engine’s combustion chambers. Without pre-cooling, the heat generated by compression would make the air hot enough to melt the engine.

The challenge for the engineers was to find a way to cool the air quickly without frost forming on the heat exchanger, which would clog it up and stop it working.

Using a nest of fine pipes that resemble a large wire coil, the engineers have managed to get round this fatal problem that would normally follow from such rapid cooling of the moisture in atmospheric air.

They are tight-lipped on exactly how they managed to do it.

“We are not going to tell you how this works,” said the company’s chief designer Richard Varvill, who started his career at the military engine division of Rolls-Royce. “It is our most closely guarded secret.”

[adrotate group=”3″]

Once fully developed, the Skylon will travel five times the speed of sound and reach an altitude of nearly 30 km — which is 20% of the speed and altitude required to reach orbit. To make it all the way into space, the plane will switch to rocket mode.


Annotated cutaway of the new Sabre engine design, courtesy Reaction Engines Ltd

And Science Minister David Willetts said: “This is a remarkable achievement for a remarkable company. Reaction Engines has shown the world that Britain remains at the forefront of technological innovation. This technology could revolutionise the future of air and space travel.”

Reaction Engines have carried out more than 100 test runs of the new cooling system, using a jet engine to demonstrate that their new Sabre design will work.

Alan Bond, the engineering genius behind the invention, said: “These successful tests represent a fundamental breakthrough in propulsion technology. The Sabre engine has the potential to revolutionise our lives in the 21st century in the way the jet engine did in the 20th Century. This is the proudest moment of my life.”

The company will now look for £250 million investment for the next step towards developing two planes, the hypersonic LapCat that will be able to carry 300 passengers around the world in less than four hours, and Skylon which can carry astronauts, tourists, satellites and space station components into orbit.


Impression of Skylon taking off for a mission into space, courtesy Reaction Engines Ltd

Skylon resembles a sleek aircraft with 82-meter long fuselage made from carbon-fiber reinforced plastic with a black ceramic skin to protect against the heat of re-entry. It will be powered by two Sabre engines.

When Skylon returns to land like a normal aircraft, it can be readied for its next mission in just hours. It will cut the cost of a space launch to around £6.5 million, a tenth of the current cost, making it an exciting possible contender to replace the work of the space shuttle.

Speaking exclusively to Skymania, Alan said: “We’ve already shown we can fly from Brussels to Sydney in 4h 40m and that is under current air traffic control conditions, that’s not some hypothetical, theoretical sort of flight plan, that’s a realistic flight plan.

“It won’t be a rich man’s aircraft. Obviously you have to make certain assumptions of what is going to happen in 25 years time. If hydrogen fuel is not with us now, it will be by then, so you have to make some assumptions about what that fuel infrastructure is going to cost. But the indications are that all first class and business class people would go by that at the same ticket price relatively as they pay at the present time to take 21 hours to get there.”

We asked Alan if he worried about running up against vested interests from established players in the aerospace industry. He replied: “We’ve already run up against that. But we’re here with a piece of test kit – this isn’t a mock-up, this is a piece straight off our test site. So the people with a vested interest had better start taking notice.”

Source: (1), (2)

Related Posts:

Please Share

  • Facebook
  • Twitter
  • Google Plus
  • Delicious
  • Email


  1. Skylon Sabre powered space plane will be the next space shuttle. Skylon can takeoff and land at the same runway, turn around time only 2 days. Built and developed in England.
    flys at mach 5. Paired with Bigelows commercial space stations and end the space race.

Leave a Reply