One of my childhood treasures is a slim book called Inside Information on Space Travel, which was published in 1970 and has cutaway diagrams of various spacecraft, from Sputnik 1 forward in time – via Black Arrow, communications satellites and Apollo – to the Space Shuttle (or a rather oddly-shaped Shuttle as it was envisaged in those days, before it became a reality.) The final page has a picture of a futuristic, sleek-looking spacecraft, accompanied by the following text:
WHAT OF THE FUTURE? A space liner like this will shuttle passengers between earth and orbiting space stations in the late 1970′s. It will be a combination of aircraft and space ship and will be able to take-off and return to land-based space ports.
Maybe there is an alternative dimension where space liners actually did start to operate in the late 1970s, but not in this particular universe, sadly. However, spaceplanes are on the drawing board and a technology that might power them was tested to destruction again last week. A scramjet could propel a vehicle up into Earth orbit, as an air-breathing engine of this kind is theoretically capable of providing the sheer power needed to climb up and out of the planet’s gravity well, and the U.S. military carried out its latest attempt to fly a prototype, over the sea off Southern California last Tuesday.
This trial, like the others before it, ended in failure, when the machine – the hypersonic X-51A “Waverider” – crashed into the ocean, due to a faulty control fin, before the scramjet engine could even be ignited. So it’s really still early days, and we won’t be able to ride in comfort up to space or across to a distant continent in one of those, to the music of Johann Strauss’s Blue Danube waltz (one of my favourite moments from 2001: A Space Odyssey) for some years yet.
Spaceplanes are taking shape, though – on paper and on computer screens. One promising (and British!) example is the Skylon, which is a hydrogen powered spaceplane that could take off from a conventional runway; the SABRE engine powering this vehicle would be an air-breather, technically not a scramjet but a kind of jet/rocket combination.
The Skylon remains a wonderful idea, but at the moment only the military appear to be actually building and testing anything similar, and their motivation, as you’d imagine, has to do with war and the capability of delivering some sort of explosive payload anywhere on the planet within minutes of launching.
However, military technology has a habit of trickling down to the rest of us, given time. The jet engine is an example of this, of course – swiftly developed during World War II (although the concept and early development of the jet engine pre-dates the war), but now powering civilian airliners across the globe, 24/7. And so is the internet. Eventually, something of the sort will be available for the likes of you and me – and even if there is no space station for us to rendezvous with, there’s always the promise of being able to hop from London over to Sydney, or Tokyo or Honolulu in a couple of hours. It would probably be very expensive but you might even be able to commute!
The military appeal of spaceplanes concerns the fact that satellites and ballistic missiles obviously follow easy-to-determine trajectories, so the enemy can comfortably stop them. With a spaceplane things are radically different.
True – I suppose in that way, they’re a bit like nuclear subs (only faster, more visible and in the air rather than in the ocean)..
Imagine…a radar-invisible spaceplane…
Yes, and I can see why the Chinese, for instance, might not like that idea one bit!