How long would it take to build a colonization ship?

Question

I am creating a history for my galactic civilization, and was thinking that the first colonization ship might be launched around the year 2200.

World War Three

Just a few years from now, a third world war breaks out. It lasts for about 5 years. Afterward, all counties end up joining the GU (Global Union). Those that don't do so willingly are forced into submission.

Space Discovery

With the GU uniting everybody, far more effort can be put into scientific advances. The mars landing takes place in the early 2030s, and the first probes to Alpha Centauri are launched (Breakthrough Starshot).

Edit:

The space discoveries actually happen decades after the war.

Colonization Age

In the 2050s, humans begin to colonize the solar system. Mars, as well as many moons, are soon being inhabited, both on the ground and with space stations.

Corporate War

The colonization of the solar system continues through 2100. The GU is still working, but corporations are becoming more and more powerful. Eventually, in 2140, a war breaks out between them. It lasts for about 20 years, until it is stopped by the GU.

Launch of Colonization Ship

In 2200, the first colonization ship is launched heading to Alpha Centauri. It will arrive 40 years later, and mark the human race becoming interstellar.

The Ship

The ship would be capable of going 0.1 times the speed of light. It would have more than enough room for 40,000 people, as well as plenty of supplies for establishing a colony upon arrival.

The Question(s)

Would it be possible to have such a ship ready for launch by 2200 under the circumstances described? When would construction have to begin? And if the proposed time frame is not long enough, how much time would be required?

Edit:

The ship will be a metal construct assembled in space, using materials acquired with relatively advanced mining equipment from various planets in our solar system. It will likely be more or less a generation ship, but since the journey will only take 40 years, the original crew will still be alive during arrival.

Answer 1

Assuming the engineering problems of such a large spaceship is solved and they can tow a lot of watery comets along with them, I'd say yes, the time frame can work, and could be built in only a few years if you don't have to worry about price for getting material into/from space. Stocking and getting everyone into it would take a bit longer, but still less than a decade.

Currently, the largest cruise ships can hold a max of about 6,500 passengers plus about 2,500 crew, for a total of 9,000, and can be built in 3-4 years. Since your colony ship likely won't have as many zip lines or shopping centers, your colony ship would need to be about 3 of these large cruise ships in size for living and recreation areas alone. Since we can make several of these ships already, having one larger one in space is feasible if enough money is available.

However, you will need a large hydroponics area for feeding 40,000 people. According to this question, a square kilometer of hydroponics can feed about 13,000 people. Assuming crops are more filling in 2200, plus advances as a result of successfully colonizing Mars, let's say a really efficient, 2 square kilometer hydroponics farm can feed your colonists. According to the cruise ship's website, it has about 1.6 million square feet of air conditioned space, or about 0.15 square kilometers. For easy math, let's generously round that up 0.25 for total area, you'd need to tape another 8 cruise ships to your colony ship. Again, we've built that many on earth, so still feasible.

The main issues you'll run into is water storage and materials for repairing the ship along the way. You can't grow water, so either you take 40 years worth of water with you(too many cruise ships), or you grab a pile of icy comets on your way out of the solar system. You also can't grow metal, so you'd need to grab some metal rich asteroids as well.

So, in summary:

The logistics/time frame to build the colony ship is fine. 3 cruise ships for living/recreation, 8 for food. A couple extra for storage. Even if they aren't built in parallel, 3 years for each is about 40 years to build that many cruise ships, so your colony ship would be quicker than that, especially since your space infrastructure seems to be robust.

Supplies might be hard to store/bring with you, however dragging along enough icy comets can solve water problems, and rocky ones can solve materials for repairing the ship along the way.

Answer 2

With enough money, anything is possible, but no, I don't think we could slow-boat by 2200.

It just isn't enough time to figure out how to live in space. In your model, we have been cruising around Sol for 170 years. Any trip to a neighboring system would take longer - perhaps a lot longer, depending on where the next habitable planet is.

There are just so many things that could go wrong - problems we don't even think to anticipate.

The hard part, in my opinion, is the ecology of a colony ship: Creating an ecosystem capable of safely supporting a human community for hundreds of years without any outside input.

Can it be done? Absolutely. Would I step onto one of these ecosystems unless they were already a proven technology, perfected in orbit around Sol? Hell no!

Then what do you do when you get there? We have never colonized another planet before. We need to be prepared for it to go wrong, or even to walk away from the planet and come back to Sol.

Answer 3

I'd quibble with your politics. A one-world government would surely quickly become a heavily bureaucratic government and likely a tyrannical government, as there would be no outside forces they would need to compete with. It is not at all clear that such a society would have rapid technological progress. A one-world government would have every incentive to oppose colonizing other planets: people on other planets would be hard to control and would likely become a breeding ground for dangerous non-conformist ideas, maybe even revolution.

But regardless, even assuming that this society or some other hypothetical society had roaring technology and the spirit of adventure to want to engage in space travel ...

I think it is wildly optimistic to assume that we would make even small progress to colonizing the Solar System in 170 years. Recall that from when Columbus discovered the New World to the American Revolution was 284 years. It took centuries to get from "first trip" to "a self-sufficient colony".

We have yet to send human beings farther than the Moon. Planting even a tiny research post on Mars or the asteroids is a daunting challenge. Even if a major nation or corporation was willing to devote tens of billions to the project, it's not at all clear that it could be done successfully.

Yes, we have superior technology now to what the early settlers in America had. But the challenges in colonizing the planets are also greater. I think it likely we will eventually terraform Mars, but how long will that take? I'd guess centuries.

It's easy to get arrogant and suppose that we are so advanced that we could do anything if we just put our minds to it. But there is so much we don't know. For example, just recently I read about an experiment to construct an enclosed biosphere that ran into trouble because, it turned out, trees can't grow properly without wind. (This isn't the article but I think it's the same experiment: http://awesci.com/the-role-of-wind-in-a-trees-life/) They had never thought of that. How many other subtle things like that go into making a viable self-contained biosphere? We're not even talking some subtle, microscopic factor in a chromosome. We're talking about ... wind.

No one is devoting major resources to colonizing the planets today because, despite all the talk of the world being overpopulated, there's still plenty of empty land, and the risks and costs of colonizing Mars are way higher than the risks and costs of colonizing, say, a desert, or the Antarctic. As a science fiction fan, I love the idea of living on Mars, or at least visiting before I die. But I really doubt it's going to happen in my lifetime.

Likewise, once we do reach the planets, it will be many centuries before the solar system is fully colonized, to the point where an expedition to another star is worth the cost. I'm sure we'd do it well before it was economically viable for the fun and adventure. Or, as people who try to sound sophisticated put it, "for scientific research purposes". But I think a colony in another solar system is many centuries away.