Future tech Generation ship

Barring a propulsion breakthrough, humanity’s best chance of reaching other star systems could be generation ships: flying colonies that would spend centuries in transit

Meet the flying colonies that'll get humanity to the stars

While we still struggle to scale interplanetary distances, various research groups have carried out serious study into interstellar travel. These distances are inconceivably vast – our nearest stellar neighbour, a red dwarf called Proxima Centauri, is about 4.25 light years or over 40 trillion kilometres (25 trillion miles) away. Though we are accustomed to the idea of skipping between star systems through fiction, barring a breakthrough propulsion discovery the best propulsion systems we can foresee would still take us a century to reach Proxima Centauri. This has led some writers and researchers to propose generation ships. A generation ship is the concept of a large, self-sustaining space colony where several generations of space travellers would live over the century, or even centuries, it would take to reach another star system. But such a ship proposes myriad questions, both technical and ethical.

To be able to make a journey a ship needs an engine, and remarkably we already have an interstellar-capable propulsion system within reach, though with one big drawback. Project Orion was a large scale, serious project studied by the US between 1958 and 1963 to propel a spaceship by detonating atomic bombs behind it. Rather than destroy the ship, bombs of just the right size would push a prospective ship along by impinging on a suspended pusher plate – like a giant atomic pogo stick! It was determined that this approach would actually be very efficient, and because the energy packets are so large the engine needs a large ship to go with it. Baseline studies proposed a 40-metre (131-foot) diameter dome weighing 4,000 tons that would be able to go from Earth’s surface, to Jovian orbit and back again in a single stage. In the end it was determined that one flight to Mars would statistically kill 100 people globally by the nuclear pollution that would be sucked back to Earth by our magnetic field. But if fired up at a safe distance in a solar orbit an Orion could ultimately achieve 10 per cent the speed of light; it is an interstellar engine we already know how to build.

Another issue we need to tackle just to live in free-floating space colonies for any time, travelling or not, is radiation protection. High-energy cosmic rays and particles of all types surge around space, and without a planetary atmosphere or magnetic field humans are vulnerable to long-term damage from them. To this end researchers at Rutherford Appleton Laboratory in the UK are working on a way to generate an artificial magnetic bubble

around a spacecraft.

This would redirect cosmic radiation around the ship protecting the crew, just like Star Trek. Initial testing is looking promising, but it will need a lot of electricity, so the ship will need its own nuclear power station on board to run everything. And there’s going to be a lot to power; one study suggested the ship would need to set off with more than 160 people on board to ensure genetic diversity over the flight time. That’s a big ship and a lot of people needing air and water constantly cleaned and recycled, not to mention food production. Food would have to be made as efficiently as possible using the least

energy, volume and water. Plants could be grown hydroponically in liquid rather than soil, algae and mushrooms could be cultured in vats for protein, and fish could probably be effectively farmed. On top of all of that the whole structure will have to spin to provide gravity.

Perhaps larger than the technical challenges are the ethical ones; travellers setting off on a generation ship are compelling their initial descendants to spend their whole lives in a small, closed community and environment on the basis later descendants might get to settle on a new planet. To ensure a healthy community who you pair up with to have children may be based on your genetic files rather than your interests. Automation should enable reasonable free time, but to keep a closed environment running for centuries will mean career choices will be limited to what needs doing. There would also be no escape if the community turned totalitarian, or if illness struck. What about the mental well-being of the crew if 100 years into the flight a warpship turns up to collect them having been invented in the meantime?

Generation ships are probably possible within the next 100 years, but are probably only ethical if Earth is otherwise lost… Probably best if we wait on the warpdrive.