UK Skylon spaceplane set for engine test in '3-4 years'
Also - fly to the space station with Brian Blessed!
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.
..."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." Would love to see these guys succeed would give a massive boost to the space industries.
In space no one can hear you scream...
...unless you are Brian Blessed.
Some things even the cold vacuum of space cannot handle.
"Let's see. We have a matt black spaceship spending quite a lot of its time in strong direct sunlight ... i"
Such quickness in putting fingers to keyboard. You might have read a bit of background first (and there's *plenty* of it)
The vehicle is matt black because that's the default color (Yes Black is not a color but it is commonly descried as such) of the French made carbon fibre (IIRC) reinforced SiC composite they are planning to make the aeroshell out of.
*Unlike* conventional rocket structures it is a separate aeroshell/insulation/ truss structure/tank design.
The insulation is is a mix of spray on PU foam on the tanks and multi layer insulation or MLI. The vehicle vents (like the Shuttle payload bay) as it ascends so the MLI acts as a series of convection stop layers and reflectors of all radiation. MLI is the *most* effect insulation *provided* the separate layers are kept at vacuum, which they will be in orbit.
"it has liquid helium tanks for cooling air on the way up, which will require some sort of refrigeration .."
Wrong. The helium operates in a closed loop heat exchanger. It is used to transfer heat out of the *incoming* air and into the *Hydrogen*. This design reduces overall system weight. The loop is going to be fairly high pressure so while at *room* pressure LH2 is *not* cold enough to return He to liquid it *might* be at higher pressure.
(unless vented to space?)
As it happens Skylon carries *more* LH2 than needed and does indeed dump the excess into a spillway where it is burnt with some of the onboard LOX to offset some of the losses.
Realizing this *is* the best use of *most* of the LH2 used to cool the airflow is one of the *critical* features of the design.
"oh yes and it also has fuel tanks which have had heat dumped into them... "
No. It has *fuel* that has heat dumped into it before being partly routed to the engines and the rest dumped. there is a difference.
lightly broiled passengers not optional I take it?
Passengers (and crew) are optional. Despite what people may think ascent and descent heating are actually on *very* different scales, by one or two *orders* of magnitude.
Unlike the Shuttle (which is pretty dense) Skylon (once its tanks are empty) is a *very* large structure with relatively little left inside it. this gives it a *very* low area loading. Big area + Low area loading + good aerodynamics = *gradual* fairly slow heating, allowing that black skin to re-radiate the heat back out into space.
There are question marks over some aspects of the design but you'd have to actually *read* something about it to identify them.