Original URL: http://www.theregister.co.uk/2010/07/22/skylon_engine_tests_farnborough/

UK Skylon spaceplane set for engine test in '3-4 years'

Also - fly to the space station with Brian Blessed!

By Lewis Page

Posted in Science, 22nd July 2010 11:32 GMT

Farnborough Reaction Engines, the British firm aiming to build an enhanced "Skylon" space shuttle which would take off from a runway without external tank or boosters, says it expects to test its revolutionary "SABRE" rocket/jet engine within "three to four years".

Here's the basic Skylon movie, for those few Reg readers who may not have seen it already:

A team from Reaction Engines, like everyone else in the aerospace world, is at the Farnborough Airshow this week and the Reg spaceplane desk got the chance to have a chat with the firm's technical director Richard Varvill.

According to Varvill, Reaction Engines is gradually closing in on the goal of building and testing a SABRE engine at last. The SABRE burns hydrogen fuel, from takeoff up to Mach 5 using the surrounding air to provide oxygen. It isn't a ram or scram jet, however: the incoming air is compressed and almost instantly chilled to the point where it is about to liquefy, using a turbocompressor and tremendously powerful freezer kit running on a closed liquid-helium loop. Then the supercold air is fed into the combustion chamber and used to burn hydrogen. The heat arising from the super air chilling process is dumped into the liquid hydrogen fuel.

As a Skylon accelerates through Mach 5.5, it will have climbed to such heights that the air is no longer worth scooping. The intakes are shut off and liquid oxygen from the ship's tanks used instead, as the SABREs become relatively normal liquid fuelled rocket engines.

The SABRE is very much the key to Skylon's success, then, so it will be difficult for the spaceplane design to be much further refined until the radical space motor can be tested.

According to Varvill, that's now on the horizon. A test project to show the validity of the pre-cooler technology is under way for tests by Reaction Engines, while the German space agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) is to try out the novel air- or oxygen-cooled combustion chamber.

With those tests set to complete in 2011, assuming no unpleasant surprises, Varvill expects that "the powers that be will ask us to build a complete test engine". He said this could be in tests within "three to four years".

Reaction Engines' work is funded partly by the European Space Agency - to which the UK government contributes - and partly by private investors. Varvill says that as the technology progresses, mainstream commercial backers are becoming more and more interested: full-blown orbital space is a huge market (unlike the suborbital sector targeted by most "new space" firms), so a realistic prospect of lower cost launch is a big draw.

"Merchant banks are showing interest now," he says, though declining to name any specific firms.

"The usual suspects," he says.

To offer some perspective, Reaction Engines' latest estimates indicate that fully developing the Skylon would cost around $12bn - about what it cost to get the Airbus A380 or the Ariane 5 rocket working.

New vid shows passenger ops - with Brian Blessed narrating!

While awaiting such funding, Reaction Engines designers continue to refine their plans. A basic Skylon would be unmanned, but should a customer wish to send people into space a Skylon Personnel/Logistics Module can be installed in the payload bay, able to accommodate 25 people and dock with a space station in orbit.

Here's a company vid showing SPLM ops, not yet much viewed on YouTube:

Thus far, people have not yet chosen to entrust themselves even to an unpiloted aircraft, let alone an unpiloted spaceplane. The shuttle, for instance, has a pilot, controls and conventional flight-deck windows all complete.

According to Varvill, though, the concept of a pilot is largely irrelevant to Skylon.

"Computers can fly it far more safely than a human," he says. "There would have to be computers in the loop even if you wanted to have a pilot for some reason."

The Reaction Engines website concedes that passenger-carrying Skylons would probably have a "captain", though Varvill prefers the term "airline representative". Whatever this supercargo/passenger-relations person was called, they would have to ride in the payload bay without windows like everyone else, much though ordinary aeroplane pilots are so far resisting this sort of thing.

Another nifty gadget the Reaction Engines boffins have come up with is Skylon Upper Stage (SUS). This is a small robot rocket designed to be attached to a geostationary satellite inside the Skylon's payload bay. On arrival in low orbit, the SUS and its cargo leave the bay and the satellite is boosted onward to high geostationary orbit, which the Skylon mothership itself cannot reach.

Having placed the satellite, the SUS can then return to rendezvous with the Skylon and be stowed away again in the payload bay for return to Earth, refuelling and re-use.

"The main market is geostationary," says Varvill. "Skylon needs to be able to do that right away."

In the longer term, Reaction Engines considers that it would be more efficient to leave orbital-transfer ships permanently in orbit for such tasks. These would collect their cargoes (and refuel) from Skylons. The company also has ambitious plans for orbiting shipyards in which missions to the planets might be assembled, powered by fuel cells, wrapped in Mylar against micrometeorites and internally floodlit to deal with the frequent pitch blackness experienced by low-orbiting spacecraft.

Varvill considers that all this might be reality in "20 years". He concedes, however, that Reaction Engines has been in operation since the 1980s, when the proposed UK "HOTOL" spaceplane project foundered - so it's been 20 years already.

But you have to say that Skylon seems at least as much worth spending $12bn to develop as the A380 or Ariane 5. We here on the Reg spaceplane desk at least will be hoping that the world does see a successful SABRE test within a few years. ®