The future of space travel

29 May 2018

Interview with

James Sadler, Airbus Defense and Space UK

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What will our rockets of the future look like? Presenter Izzie Clarke asked the public and then spoke to James Sadler from Airbus Defense and Space UK, who designs propulsion systems.

Person #1 - Very very very large probably fit like...tens of thousands of people on there.

Person #2 - I don't think they'll exist. I think it'd be a star trek one. Beam Me Up Scotty.

Person #3 - Super sleek, I don’t know what else, you literally don’t have to do anything, someone’s got those like, full of robots.

Person #4 - They're probably start off quite small to be honest. Because they probably might, I don't know, go mining first.

Izzie - Well, what do the experts think?

James - I'm a bit of an optimist. I would like to think that the human race will do very well in terms of space travel.

Izzie - That's James Sadler from Airbus Defense and Space UK who designs propulsion systems.

James - There's these devices called O'Neills Cylinders which are basically very large space stations which spin in space. So they have the appearance of having gravity but of course you can have more of them based around Mars, Venus, Earth, they would be able to act as refueling stations, stop offs if you're going for a deep space journey or even you could imagine it a bit like a cruise ship where you go from port to port and the space stations become the ports.

Izzie - That may sound like something from Guardians Of The Galaxy but NASA has a look into these spaceports and whilst it's theoretically possible it's just too expensive. Current spacecraft use chemical components: a fuel and an oxidizer which essentially start a massive fire and the rocket blasts off like a firework.

James - The better the propulsion system you have, the faster you can get somewhere or the further you can go. At the moment if we wanted to go and take the human race somewhere else we would be limited probably to Mars at a stretch. If we were looking to go even further into space and we wanted to go out to another star system for instance, say for instance we found another habitable planet nearby, the technologies to do that for a human ship do not currently exist. But if we wanted to go and have a look we would be able for instance to send very very small spacecraft, say the size of a postage stamp, using some very novel techniques where we use a solar sail.

So we have this very light material which stretches for a long way away from this very small spacecraft and we can use lasers or the sunlight to push very gently against it for a very long period of time. So it's a bit like sailing on the sea and a gentle breeze you're not going to go anywhere very fast but over a period of time you can get faster and faster and it might give you enough push to get away.

Izzie -  But not exactly ideal for us humans

James -  We’re now looking at the next generation which is the electric propulsion. The way it works is you take an inert gas. In our case we usually use Xenon and you knock some of the electrons off it to give it a charge. Once it's got a charge you can use electric fields to give it some speed. And in this case you would be able to take an ion and take it up to about 35 kilometers per second in terms of the speed it would come out of the back of that rocket.

Izzie - And so does that then give it a bit of a push and that's what allows us to keep moving.

James - Exactly. So what you have is a combination of mass and speed which gives you a momentum. Every time you take a piece of mass and you chuck it out the back of the rocket at speed you acquire that momentum yourself. The faster you can throw a mass out the back, the more momentum you get or the higher the mass you throw out at a lower speed the more momentum you get. In electric rockets, the idea is that you throw very small masses very fast whereas in conventional chemical rockets we throw a lot of mass a lot more slowly and that's where the efficiency of electric propulsion comes from.

Izzie - There's also a certain engine that’s both efficient and gives you sufficient thrust a VASIMR engine. These could get us to Mars in three months, rather than eight months to a year.

James - They work by turning matter into its fourth state so they take a conventional gas and ionize it into a plasma, or once it's in plasma form it's easier to inject large amounts of energy in through various forms like radiofrequency heating which allows the temperature of the gas to be taken up to say million degrees so hotter than the surface of the sun. And then you can eject out of the back in a more efficient way which gets you a higher level of miles per gallon but also then gets you that higher thrust.

Izzie - How soon do you think this might happen. If it does at all.

James - There's a saying in the space industry as well as the nuclear industry that it's always 50 years away. So 50 years ago they thought it would be done today and today we think it's about 30 to 50 years away as well.

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