As I report elsewhere in this edition, Sir Richard Branson and his Virgin Galactic company announced at the recent Farnborough International Air Show, in the UK, that they would be offering small satellite launch services, using a rocket now under development, called LauncherOne, that would be dropped from the company’s WhiteKnightTwo carrier aircraft.
This is not a new concept. US company Orbital has been successfully launching small satellites in its Pegasus rocket, dropped from a converted Lockheed Martin Tristar airliner, for 22 years now.
An even more radical approach is under development in the UK. There, a company called Reaction Engines has been developing its Synergetic Airbreathing Rocket Engine, better known as Sabre, for the past 20 years. This engine would power a spaceplane, which would take off from, and land on, runways like a conventional aircraft.
For takeoff and flight through the lower atmosphere, the Sabre power plant would ingest air and burn the oxygen within that air with liquid hydrogen fuel in the rocket combustion chamber. Once the air becomes too thin to use, the engine would switch to on-board liquid hydrogen. (So the Sabre is a composite jet engine/rocket engine design.) This would reduce the amount of on-board liquid hydrogen needed to launch the craft into orbit by more than 250 t!
The need for extra stages, jettisoned after the fuel has been exhausted, would be eliminated, making the single-stage-to-orbit spaceplane concept practical. Reaction Engines is developing a design for such a spaceplane, which it calls the Skylon. This would be an unmanned craft, capable of lifting 12 t or more of payload into orbit. The European Space Agency (ESA) has con- cluded that, provided the Sabre can be successfully developed, the Skylon concept is practical using today’s technology.
The problem with the Sabre pro- gramme is that it has to overcome huge technological problems. The spaceplane will hit high speeds in the lower atmosphere, with the result that as the air enters the engine intake and is compressed, its temperature will soar to 1 000º C, which would melt the intake and engine. So the air has to be cooled very fast and very deeply before it can enter the compressor. This is done by using a precooler. However, previous precooler designs tended to freeze out the moisture in the air, covering the precooler with a layer of frost and disrupting its operation.
Reaction Engines has developed a precooler module containing networks of very fine pipes which circulate liquid helium. This should drop the temperature of the incoming air to –140º C in just 0.01 seconds! This precooler is now being tested, with some 66% of the programme now concluded. So far, the company reports things are going well. Progress is being monitored and audited by the ESA, at the request of the UK Space Agency. (The ESA has experts in propulsion engineering and technologies, which the UK agency does not.)
Now, Pegasus and Launcher- One can transform the small satellite launch sector, while Sabre/Skylon can completely revolutionise earth-to-orbit operations. Interestingly, both Orbital and Virgin Galactic are entirely private-sector operations. Reaction Engines is also a private-sector company, and only 15% of its funding has come from the UK government – the balance has come from private investors.
Should the precooler pass all its tests, it is quite likely that the British government will provide more funding to further develop the engine – but, again, the bulk will have to come from private sources. Perhaps, more importantly, the British authorities are already working to develop the regulations necessary to allow the operation of spaceplanes in both UK and European airspace.
Britain’s civil space budget is some £300-million but the British civil space industry has brought £9.1-billion into the UK economy since 2010. The global recession has had no discernible impact on the country’s space industry. The UK’s approach to the space industry is for the State to make investments in strategic technology development programmes being undertaken by the country’s space companies (whether locally owned or local subsidiaries of multinational aerospace corporations) to stimulate the development of new technologies. Once the technology is proven, the private sector commercialises and markets it.
Thus, recent State investments worth £40-million stimulated private investments of more than £500-million in the British space industry. To give a specific exam- ple, the UK is giving Surrey Satellite Technology Limited (a British subsidiary of EADS Astrium) £21-million to develop and launch the first of a new design of small radar satellites, called NovoSAR. (The payload will be provided by Astrium UK.) This will open a whole new market for the company, which will be able to provide radar satellites to countries that could not previously acquire this technology.
Americans talk a lot about getting the private sector into space, but it is the British who have been doing it. The ESA is now adopting the British model. Perhaps South Africa should consider doing the same?