The future of space travel
It sounds like there are some pretty exciting planets out there in space, but will we ever be able to explore them? In the Star Wars films, practically everyone is accustomed to hopping from planet to planet, whether it be in an Imperial Star Destroyer, X-Wing fighter, or the Millennium Falcon itself. Katie Haylor spoke to Liz Seward, from airbus Space and Defense, to find out more about space travel. First off Katie asked how a traditional rocket works...
Liz - Rockets have been around for a really long time. The first known rocket is actually from 400 BC, in Greece, where a steam powered pigeon flew down a wire, so it got propelled by steam out of the wings. Then the Chinese filled bamboo tubes with gunpowder; they actually used them how to fire arrows in war, and then they turned them into fireworks.
So it’s been around for a long time, but modern rockets came about really from the early 1900s when they started looking at liquid propulsion and making them bigger. Our rockets nowadays work either by using solid rocket boosters, like giant versions of the Chinese rockets. They were the boosters on the side of the space shuttle, and it’s a mixture of fuel and oxidiser mixed together as a solid and once you set fire to it, it will continue to burn until all that fuel is used up, so there’s no way of turning it off.
Then we have liquid engines where you have big tanks, one with an oxidiser, one with a fuel, and they meet in a combustion chamber. Then as they ignite, fire and gas propels itself out of the end of the rocket, and this is better because you can turn it on and off by controlling the gas flow. If we go back to our physics from school, Newton’s third law says: if you’ve got a force in one direction you have to have an equal and opposite force in the other direction. So you shoot this hot burning gas at high speeds out of the end of your rocket and that propels you up and, in our case, out of the atmosphere and into space.
Katie - What are we using rockets for now; are we using them for space travel?
Liz - Yes. We use them to get out of the Earth’s gravity well - we sit inside the gravity well of the Earth and so we fire ourselves up into space and to orbit. At the minute we take people to the International Space Station or satellites to orbit the Earth, from telecom satellites to your GPS signals, to things exploring our solar system.
Katie - On that note then what, as we’re getting to the end of the year it seemed appropriate to frame it like this, what are the biggest achievements that have been made in space travel?
Liz - We’re looking at ion drives at the minute. They’re used in Star Wars to propel themselves around the solar system, and it’s ions as in atoms and molecules that get fire out of the back of a spaceship. In our case we’re using them in satellites. In Airbus we are changing our chemical propulsion systems once in space to ion drives, electric drives. They work by firing tiny charged particles out of an engine so the thrust that you get is very low, but you can do it for a very long time.
So we change the travel journey from near-Earth orbit to geostationary orbit, 36,000 kilometres away, where all of the telecoms satellites sit. It takes three days with chemicals and six months with an electric propulsion, but you save 40% of your fuel mass so you can take 40% more payload, or have a smaller, cheaper satellite. So it’s very attractive.
Katie - Is it an example then of taking something from sci-fi through to sci-fact; something that was originally in Star Wars and then we started working on it or the other way round?
Liz - Oh that’s a good question. I think that science fiction has been looking at this for a long time, but earthbound versions of the way that the method of this works, the field effect and the hall effect have been studied in physics for a really long time too. So I think it’s earthbound physics, inspires science fiction writers, inspires earthbound physicists to again to make it real.
Katie - That’s an excellent cycle. Looking ahead then, what do you think will be the next big leaps?
Liz - Nuclear engines. One way is to have a small nuclear reactor that heats up your fuel really, really hot which means it can go much faster. If we do this it can be two times as efficient as our current rockets.
But in the 1970s there was a project by the British Interplanetary Society called Project Daedalus, which looked at using fusion, deuterium and helium-3 to power a rocket that could take you to Barnard’s star in 50 years - the star is nearly 6 light years away and you’d have to build it in orbit.
We’re getting closer to that but one of the limitations is helium-3. It doesn’t occur very naturally on Earth. We’d have to mine it from the Moon or, in the proposal, they actually would send a hot air balloon to Jupiter to mine it in Jupiter and send it back to Earth.
Katie - Okay. So how on earth do we end up getting helium-3 then; is this a possibility?
Liz - We’re getting closer to be able to mine it from the Moon. We’re definitely nowhere near getting it from Jupiter in a hot air balloon. But one big push at the minute is having a moon village - it’s proposed by the European Space Agency, and the rocket’s being developed, the Americans have something called the SLS rocket. It’s just a bigger version of our current ones but their plan is to go the the Moon and then Mars. People are really interested in going to the Moon because you can mine helium-3 there and if we get that in large quantities it may change the way that we produce energy, and it may also change the way we do space travel.