Articles
Dr Christopher MacLeod, engineering lecturer at the University of the Highlands and Islands
There is a new space race in the offing. Unlike the first space race, this one is being led by companies, rather than countries. The likes of Virgin Galactic, Space X and Blue Origin are at the vanguard of the latest developments.
But most of these companies are developing conventional rocket technology which is too expensive, dangerous and not reusable – and so will not lead to cheap mass access to space.
The big problem with conventional rocketry is that it is not “air breathing” – this means, that, unlike a jet engine, it has to carry its own oxygen with it to burn its fuel. This oxygen is stored in massive tanks on the vehicle and weighs up to eight times more than the fuel itself.
However, for much of the way up the craft is passing through perfectly good air. If we can collect this air and use it to burn the fuel, then one of the major problems with access to space will be solved. This could allow the production of space-planes that take off and land on conventional airstrips and so negate the huge logistical issues surrounding rocket launches.
One type of engine, which has been around for 60 years and aims to solve this problem, is called the scramjet. But in all that time no one has ever got it to work satisfactorily. The engine is moving faster than five times the speed of sound and there is no way of getting the fuel and air to mix properly at this immense speed.
The engine we are developing at the University of the Highlands and Islands works in a completely different way to the scramjet. A rotating nose-cone diverts the air away from the main engine, while fuel, in the form of solid pellets, liquid drops or gaseous capsules, is dropped into the engine duct. The main airflow is then diverted back into the path of the fuel pellets and envelops them. This distributes the contents evenly through the air and ensures that the fuel and air completely mix ready for combustion.
We are talking to other academic institutions and potential commercial partners with a view to testing this idea outside of simulation in special high-speed facilities called shock-tunnels. Following this, we hope to build a single-speed prototype, which could be tested on a “sounding rocket” before building a full-sized prototype.
Cheap and safe access to space will allow advanced manufacturing, new sources of energy, safe disposal of chemical and nuclear waste, and mining of minerals, to name but a few benefits.
Even if current ideas don’t succeed, space tourism, in the form of joyrides into the upper atmosphere, will probably take off in the next few years. And the UK could end up with several facilities for horizontal take off and landing.
The biggest hurdle for the space industry in this country is the idea that space and aeronautics are separate. The UK Space Agency deals with objects in space, such as satellites, and generally not with launch ideas.
Yet the current bottleneck and the coming revolution will be about getting into space. This is the reason why Nasa is the National Aeronautics and Space Administration – the Americans have it right and we have it wrong.