In the news: Reaction Engines Skylon

For round one, I'm looking at a recent piece of news that lends legitimacy to a program I view as fascinating, but a big risk technologically. The latest news from the UK is that the British National Space Center in conjunction with the ESA, will be pumping 1,000,000 euros into Reaction Engines' Skylon space plane and it's SABRE engine technology. This shows some serious long term thought on the part of the BNSC and the ESA on a risky, but potentially revolutionary technology. So let's take a quick look at the Skylon and it's remarkable engine.

The skylon is meant to be a solution to the single stage to orbit challenge. A spaceplane in the truest sense of the term, it is meant to take you from Earth's surface to orbit without any kind of booster separate from the main vehicle. They aim to do this by using a fairly simple liquid hydrogen and liquid oxygen (LOX) reaction leaving behind water and a lot of thrust. The same principle is used to get the shuttle from booster separation to orbit. The reason the shuttle can't do single stage to orbit, however, is the large amount of both hydrogen and LOX needed to reach orbital velocities. The holy grail of single stage to orbit craft is to find some way to take up less fuel.

The SABRE engine, if the concept is to work, solves this problem by making the LOX as it goes along. As with anything in the rocket science world, this is not as simple as it sounds. It's not like a person can go out and buy a LOX kit at their local science supply store. First of all, you need to compress it. That takes energy. It turns out the most efficient way to compress standard issue Earth atmosphere into liquid oxygen is by making an open ended compressor of sorts. In other words, go really fast so that the air is crunched into a very small space.

The problem there is that the kind of compression we're talking about generates some serious heat. It's how jets fly, essentially. Compress the air inside the engine, which raises the temperature, throw in some jet fuel, and voila, you're airborne. To handle the kind of heat we're talking about, jets use some heavy duty materials. The problem with heavy duty, is essentially the 'heavy' part. What good is making your own LOX if you lose all that ground in the materials you need to make the engine. It's the ultimate yo-yo diet.

So the guys at Reaction decided to make a serious heat sink called a precooler. Again, it's nothing new, conceptually. Computer geeks have some pretty wild heat sinks tht keep their over-powered computers from turning into a heap of molten plastic. This one is somewhat similar to the water-cooled method where you run cool water through a series of hoses near the processor to cool it down. Except instead of water, the SABRE pipes compressed hydrogen and helium through the system. If you remember the liquid Nitrogen back in science class where they shattered flowers and such, that's like a pot of boiling water compared to this stuff. The end result is a system that cools the incoming air down from a hellish 1800 degress Fahrenheit to a bitterly cold -220 degrees in less than a second.

Again this is far more complicated than it sounds. There are a number of issues that had to be solved before Reaction even knew it was possible to do what they set out to do, like getting the water out of the system before the engine turns into the worlds biggest popcicle. But reaction has now proven it's possible to make it happen. But they say that if they get the funding to start production on the final product, it will be 10 to 15 years before it flies. So while I am very excited and hopeful for Skylon, it's a long way off. Kudos to the BNSC and ESA for having the foresight to realize that, without some funding, in 10 to 15 years we'd be kicking ourselves for not at least trying.