Britain’s Spaceplane Skylon – hopefully nearer to taking off!

Britain has a long engineering history when it comes to developing advanced engines from F1 motor racing to jet fighters. Sadly some potential innovations never made it to full development and manufacturing because of the short sightedness of some UK governments. The UK had a viable rocket and satellite business in the 1960s, however the government of the day withdrew funding and so from being up there with the US and USSR, Britain’s space faring became moribund. Only since the 1990s has Brit technology been a major part of collaborative space missions. Since Sir Frank Whittle an ace RAF fighter  pilot and enginer developed the first turbo jet engine in the 192os, Britain has continued to innovate jet engine technology. Rolls Royce (RR) PLC vies with US General Electric as the worlds biggest jet and turbo propulsion engine maker.  RR’s adanced engines are famous and used by many airlines, air forces and navies throughout the world.  It’s latest Trent Engines are regarded as the peak in precision engineering and will continue to be researched & developed. Rolls Royce has worked with British Aerospace and with government funding  to develop more advanced and faster engines.

Their  most famous development was HOTOL(Horizontal Take-Off and Landing), which was an all British air-breathing rocket hybrid space shuttle.

HOTOL was designed to be a single-stage-to orbit (SSTO) reusable winged vehicle launched from a rocket sledge .  It  was to be fitted with a unique air-breathing engine, the RB545  called the ‘Swallow’, developed by Rolls Royce. The engine was technically a liquid hydrogen/liquid oxygen design, but dramatically reduces the amount of oxidizer needed to be carried on board by utilising atmospheric oxygen through jet engine action as the spacecraft climbed through the lower atmosphere before rocket propellant would kick in when the air was too thin at high altitude. when the rocket propuslion was engaged on the edge of space, it could reach between mach 5-7   ( 5328 mph/8574 kph). A journey from London to Australia would take between two & three hours! With the potential amazing speeds there was much excitement generated.

HOTOL -Artists rendition

However during development, it was found that the comparatively heavy rear-mounted engine moved the center of mass of the vehicle rearwards. This meant that the vehicle had to be designed to push the center of drag as far rearward as possible to ensure stability over the entire flight regime. Redesign of the vehicle to do this cost a significant proportion of the payload, and made the economics unclear. In particular, some of the analysis seemed to indicate that similar technology applied to a pure rocket approach would give at least as good performance at lower cost. With these problems in 1988 the UK government withdrew further funding, the project was approaching the end of its design phase but the plans were still speculative and dogged with aerodynamic problems and operational disadvantages. It is moot whether these technical problems would have been overcome in short order thus  leading to distance shrinking travel, however the best was to come…

In 1989 the HOTOL co-creator  Alan Bond formed a company called Reaction Engines Limited (REL). Learning from previous development, REL began developing a successor to HOTOL with the previous technical issues eventually being solved and more innovative development introduced.

The result decades later is the  Skylon space plane,  which if it continues with the succesful development so far, will achieve what HOTOL was suppose to do  and even more. It would be a space plane more advanced than the Space Shuttle, not needing to be  attached to a large expensive rocket as the Shuttle had to be.  Skylon would take off and land on a normal runway using its own inbuilt dual propulsion system consisting of an advanced jet engine and rocket propulsion in order to achieve a speed of Mach 5 (3691 mph/5 940 kph).  A journey from Britain and Europe to Australia would take about 4 hours.

Also when Skylon reached and altitude of 26 miles (42 kms) into the sky, the rocket propulsion would then be engaged to push the space plane into orbit where it could  perform the functions of the Space Shuttle before retuning to earth. Unlike the unpowered Shuttle, Skylon woud have  it’s  own jet engine and be able to fly (and not have to glide like the Shuttle) to landing on a runway.  The payloads it would carry could be delivered into space at  a fraction of current costs. This would open up access to space on a much larger scale than having to use and rely on  large costly rockets and remote launch sites.

Skylon could be prepared and reused in a two day turnaround and could be used at least 200 times in its operational lifetime. As with HOTOL, development and evolution of Skylon would continue.

The major problem dealing with the intense heat entering the jet engine at hypersonic speeds has been solved with innovative heat exchangers that rapidly cool super hot air allowing maximum thrust to be maintained by the Sabre engine.

In November 2012,  REL based in Culham, Oxfordshire, ran a series of tests on key elements of the  Sabre propulsion system under the independent eye of the European Space Agency (ESA), who afterwards confirmed that all the demonstration objectives were met. More investment is needed and will surely come even from the British Government! REL are confident other investors seeing the enormous potential would be also interested.

I would hope that if Skylon flies commercially, it’s air fares for passengers would eventually be cheaper than the innovative British -French  Supersonic (SST) Concorde. While being the first commercial plane to travel at twice the speed of sound (Mach 2)  carrying 300 passengers, it was not truly  a commercial success due  to running costs, high fares only the wealthy could afford. A bad crash in 2000 added to falling passenger numbers. Main airline companies wanted bigger aircraft to expand First and Business Class for subsonic travel, so concorde  was retired in 2003 after 27 years service.

If Skylon development reaches maturity and it becomes a viable mode of hypersonic travel, an incredible and exciting future for both space and terrestrial travel appears to be getting nearer. It would be like the evolution from early propeller driven aircraft to the jet engine.


Skylon in orbit – artist’s rendition

Sabre Engine- Skylon- diagram

Diagram Skylon Sabre Engine intake



Take-off and Landing




Payload Capabilities




SKYLON provides no payload support being purely a transport system.






SKYLON C1 Statistics

Length 82m
Fuselage diameter: 6.25m
Wingspan: 25m
Unladen Mass 41,000kg
Fuel Mass 220,000kg
Maximum Payload Mass 12,000kg
Maximum Take-Off Mass 275,000kg

Two decades of research work has resulted in technological leadership in the areas of:

  • Ultra-lightweight heat exchangers
  • Advanced rocket nozzles
  • Combustion chamber design
  • Contra–rotating turbines
  • Lightweight airframe structures
  • Robust lightweight thermal protection systems
  • Engine and vehicles analysis software tools
Below is a short animation on SKYLON

One Response to “Britain’s Spaceplane Skylon – hopefully nearer to taking off!”

  1. Jean Morton says:

    Wow. It is all exciting. Hope it works. It would further revolutionaliised travelling. What do you think of its implication jetlagwise?

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