Space Plane Tech Could Power Hypersonic Aircraft​ for US Military

This artist's illustration depicts the Skylon concept vehicle.

Credit: Adrian Mann

Engine technology being developed for a British space plane could also find its way into hypersonic aircraft built by the U.S. military.

The U.S. Air Force Research Laboratory is studying hypersonic vehicles that would use the Synergetic Air-Breathing Rocket Engine (SABRE), which the English company Reaction Engines Ltd. is working on to power the Skylon space plane, AFRL officials said.

"AFRL is formulating plans to look at advanced vehicle concepts based on Reaction Engine's heat-exchanger technology and SABRE engine concept," officials with AFRL, which is based in Ohio, told reporters.

SABRE and Skylon were invented by Alan Bond and his team of engineers at the Abingdon, England-based Reaction Engines.

SABRE burns hydrogen and oxygen. It acts like a jet engine in Earth's thick lower atmosphere, taking in oxygen to combust with onboard liquid hydrogen.

When SABRE reaches an altitude of 16 miles (26 kilometers) and five times the speed of sound (Mach 5), however, it switches over to Skylon's onboard liquid oxygen tank to reach orbit.

Two SABREs will power the Skylon space plane, a privately funded, single-stage-to-orbit concept vehicle t-hat is 276 feet (84 meters) long. At takeoff, the plane will weigh about 303 tons (275,000 kilograms).



The SABRE heat exchanger is also known as a pre-cooler. It will cool the air entering Skylon's engines from more than 1,832 degrees Fahrenheit (1,000 degrees Celsius) down to minus 238 degrees Fahrenheit (minus 150 degrees C) in one one-hundredth of a second.

The oxygen in the chilled air will become liquid in the process.

"The [pre-cooler] performance has always been pretty much what we predicted," Bond explained to reporters at the Farnborough International Airshow in England on July 16.

"We've now done over 700 actual tests. It's now done as much service as a pre-cooler would in a real engine."

Bond's team has also successfully tested the pre-cooler for a problem aviation jet engines have to deal with: foreign objects being sucked in.

"We know it [the pre-cooler] can take debris, insects, leaves," Bond said.

SKYLON: Impoverished UK dreams of having a 'new' Spaceport on recycled aerodromes

Skylon, a concept space plane from Reaction Engines Ltd., is an entirely reusable single stage-to-orbit launch vehicle, based on revolutionary engine technology.

Credit: Adrian Mann

The UK, impoverished and technically challenged by a floundering coalition government, is hoping it could re-badge a derelict air force base as a spaceport by 2018.

Pending the usual convoluted administrative approach of a regulatory report to be published July 2014 and a technical feasibility study that is underway with the UK's National Space Technology Programme (NSTP), it may be possible that the country could convert an aging air base and claim that it hosts a spaceport, within the next five years.

A new National Space Flight Coordination Group, chaired by the UK's financially shackled Space Agency, will oversee these reports and the future work for this UK 'spaceport.'

UK Government officials made a political statement saying that they hoped this will be the start of commercial spaceflight for the country.

The politically appointed steering group and the 2018 date were announced with the publication of the "UK Government Response to the U.K. Space Innovation and Growth Strategy 2014-2030," published in November 2013 by friends in the UK aerospace industry.

This publication optimistically claims the UK's space sector could be worth 40 billion GBPs ($67 billion) by 2030. The industry is allegedly worth 9 billion GBP ($15 billion) today but most of it is sub-contracted to European (EADS) and US (Lockheed, Boeing, etc) corporations. Very little of the UK's aerospace industry is 'homegrown.'

"This [National Space Flight Coordination] group reports to [government] ministers," the government's response says.

"Its cross-cutting nature is recognition of the scale of the challenge inherent in identifying, approving and building a U.K. spaceport and in supporting all the necessary innovation and technology that it would require."



These are not the first attempts at reports and studies that the U.K. government has undertaken in its quest to appear to have a viable spaceport, it is merely the first time the government has set a date for the creation of such a facility.

In 2009, the British National Space Centre (BNSC), which preceded the U.K. Space Agency created in 2010, funded a study into spaceport candidate locations. That study concluded that Lossiemouth in Scotland would be the best site.

Located in northern Scotland, Lossiemouth is on the coast of the North Sea and has a recently-closed Royal Air Force base with a runway suitable for the types of launch systems that favour, UK Tax exile, billionaire and hedonist, Sir Richard Branson's Virgin Galactic.

The Scottish people have an excellent and long history of engineering and are renowned as innovative, motivated and dedicated engineers and scientists, but they are both politically and physically a long way from the decisions being made in London, by the London-based government, which favour developments that will boost its flagging popularity with voters in the South of England.

Skylon: Supersonic plane that could take you into Space

SKYLON is a design for an unpiloted, reusable, single-stage-to-orbit spaceplane intended to provide reliable, responsive and cost effective access to space.

Skylon is a concept by the British company Reaction Engines Limited (REL). A fleet of such vehicles is envisaged for the future.

Skylon could have a significant impact on many different space operations.

For example, it could deliver payloads to Low Earth Orbit (LEO) where these satellites or other equipment could propel themselves further out into space.

It could be configured to launch multiple small satellites at once from its cargo bay, to provide supplies for space stations in orbit, or to get space station modules, telescopes and other equipment out beyond the Earth's atmosphere in a cost-effective way.

The designers have already created a special interface through which Skylon can link to existing space stations and pass over essential supplies or even passengers.

Further down the line, Skylon could be used as a support vessel for interplanetary missions as a backup for the main spaceships.

From nose to tail Skylon measures 82m. It has a wingspan of 25m and a fuselage diameter of 6.25m.

Prototyping design work on the craft is still very much ongoing, but once the vehicle has received the necessary endurance certifications out in the wild, it will be able to fit a cabin module for transporting up to 30 passengers —eventually, you may be able to take a trip to space from your local airport.

The cabin will be completely self-contained and stored inside the aircraft's cargo bay (in early mock ups from the designers, it looks a bit like a motor home).

Upon re-entry from space, heat is radiated away from the main aeroshell using layers of reflecting foil and low-conductivity shell support posts.

This is the Sabre (Synergetic Air-Breathing Rocket Engine), a landmark breakthrough in aerospace technology that enables aircraft to reach five times the speed of sound.

The engine is built by Reaction Engines Ltd and there are already several prototype planes in the works.

Over 20 years' worth of development has gone into Sabre Engine, which offers both a rocket mode (for sending aircraft into space) and an air-breathing mode (for cruising through the sky at high speeds).

One of the biggest innovations in the engine is the way it uses oxygen already in the air rather than an on-board oxidiser, significantly reducing the weight of the engine and allowing it to operate like a normal jet engine.

Once above the atmosphere, it can switch to a conventional rocket mode using on-board liquid oxygen.

SABRE Engine: Skylon spaceplane's revolutionary engine passes key milestone

Illustration of the Skylon spaceplane powered by SABRE engines. 

Credit: REL/Adrian Mann

A revolutionary new air-breathing rocket engine designed to propel a spacecraft to orbit in a single stage has passed a critical milestone.

The engine could also revolutionise air travel, reducing journey times around the planet to under 4 hours.

The engine, called SABRE, is a hybrid of a jet engine and a rocket engine. An aircraft fitted with the engines could fly to other side of the planet in under 4 hours travelling at Mach 5.5. more than five times the speed of sound, whilst a spaceplane such as Skylon could be propelled into orbit in a single stage.

The engines breathe in air as they pass through the atmosphere, meaning the spaceship could launch without a fully laden fuel load.

However, the challenge of the design has been how to cool the huge amount of air it continuously breathes in without the engine freezing up.

The testing has proved that SABRE's pre-cooler heat exchangers can cool air from over 1,000⁰C to minus 150⁰C in less than 1/100th of a second without the engine frosting up.

The UK company which invented the new propulsion technology, Reaction Engines Limited (REL) described the successful testing as "the biggest breakthrough in aerospace propulsion technology since the invention of the jet engine".

REL has also devised a spaceplane called Skylon that would be fitted with the SABRE engines. Skylon would take off and land on runways, and would not require any part of the craft to be jettisoned during its journey to orbit.

This would make it a completely reusable spacecraft which could reduce the time and cost of launching payload into space.

REL believe the cost of launching satellites could be cut by 90% if the SABRE powered Skylon entered service.



The UK Space Agency asked experts from the European Space Agency (ESA) to validate the pre-cooler heat exchanger test results

ESA experts who reviewed the testing concluded "The pre-cooler test objectives have all been successfully met and ESA are satisfied that the tests demonstrate the technology required for the SABRE engine development."

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. Alan Bond, REL

Illustration of the SABRE engine with the location of the pre-cooler heat exchanger highlighted in blue. Credit: REL/Adrian Mann