Could We Be on the Verge of a Major Technological Transportation Breakthrough?

Have you ever wondered what space travel might be like in the future? In many science fiction stories, in the future humanity has spread out across the solar system, colonising planets and asteroids. Given the hundreds of millions of km between us and even the closest orbital bodies, this is not easy to do in real life – at least not with our current level of technology. NASA predicts that it will take 7 months to make it to even our closest neighbour, Mars. This is why sci-fi writers often invent powerful engines on their spacecraft – warp drives, Epstein drives and hyperdrives – that allow humans to cross those distances in days or minutes, rather than months or years. These conventional flight times occur because of the limitations in conventional rocketry. But new technology is arising, something that feels like it's straight out of sci-fi, that might one day completely replace conventional rockets. With its greater efficiency, those month-long flight times could become mere days. And while the technology is still under development, there are examples of it being used in outer space missions right now. What is this technology? Ion engines. And with them, the future might be a lot closer than you think.

I'm Alex McColgan, and you're watching Astrum. Join with me as we learn more about this developing technology, and learn more about these devices that may well be the future of space travel. To begin with, for those who are unfamiliar, what is an ion engine? And how are they different from the conventional rockets we know today?

All rocketry works under the principle of conservation of momentum. If you want to go up, you must send something else flying down, with enough momentum to equal the upward momentum you wish to achieve. Conventional chemical rockets do this by burning rocket fuel. Oxidiser mixes with a chemical like liquid methane, heating it and causing it to expand. By sending out this stream of highly energised exhaust from the bottom of the rocket, the top is sent flying upwards; kind of like releasing the air from inside a balloon to send it whizzing around the room. Momentum is conserved in these cases. In our example with the balloon, the momentum of the air leaving the balloon equals the momentum of the balloon flying around. With the rocket, the momentum of the exhaust equals the force of the rocket going upwards.

In theory, you could travel around in space by simply having a very large balloon and releasing its air. However, you would run into a problem with this method. You would run out of air very quickly, and then would not be able to produce any more thrust. Balloons are not very efficient forms of rocket propulsion. To a degree, this is also the problem with our current chemical rockets. Although burning the fuel does give it more kinetic energy than simply squeezing it out of a balloon, chemical rockets are still not that efficient, as there is an upper limit to how fast you can accelerate exhaust material by burning fuel. Rather than burning it hotter, if you want to go faster with such a rocket, the only solution is to burn more fuel, which means you need to carry more fuel, which means your rocket has to be bigger and heavier, requiring even more fuel. And once you run out of said fuel, that is it – you can produce no more thrust.

Conserving their fuel is the reason the NASA trip to Mars will take 7 months. There's no way they could have a large enough rocket that could carry enough fuel to accelerate passengers all the way to Mars. Consider the over 60m size of some of the rockets being launched currently, such as the Artemis 1 SLS rocket that got a spacecraft to the Moon recently – a much closer target. Its main core stage was filled to the brim with 2.

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