Assuming we are talking about an era when Sol has a thriving space industry and the Solar system is broadly colonized. Current materials science supports structures up to 8 kilometers in diameter, and if large scale graphene production is possible, up to 100km in diameter, at least according to Isaac Arthor.

I am wondering what resources would be difficult for a colony ship to reproduce in-situ on an one way trip to the first interstellar expansions of humanity. I picture a true generation ship might be primarily designed around the transport of some of the largest prefabricated sections of a future centrifugal spin gravity habitat.

  1. Using hard science to speculate, what types of materials and components would only be available with the massive industry present in humanity’s original home?

I picture the main outer ring frame structure of an O’Neil cylinder, like some kind of curved beam, would be prefabricated and sent in a few pieces for later assembly. If the O’Neil cylinder was to be 8km in diameter, 3 pieces would make the generation ship at least 5.7km long.

  1. What is practical to transport assuming fusion is in the cards, as are self replicating drones for resource extraction in a region like the astroid belt, and assuming planets are resource poor gravity prisons we avoid in favor of mobility?

  2. How might carbon get utilized for large structure fabrication in space as far as processes?

  3. What about metals and space based fabrication. How can you picture the production happening in ways that would only be possible in a highly advanced space based economy?

I know this is highly speculative and I hope the mods will let it fly to ask this. I know most nerds are curious about this kind of thing. I’m only interested in the most conservatively realistic of hard science fiction/futurism.

  • Hypx
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    10 months ago

    Yes, that’s the point. It’s far beyond the actual city of Tokyo in terms of construction difficulty and scale. But it doesn’t need any new technologies to be invented to be doable. Just the ability to build on that scale.

    • @morphballganon
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      10 months ago

      But the point is if you get your materials from the Moon, for example, it’s vastly more economical to just build a Moon colony (or another Moon colony) than a space colony of the same size.

      • Hypx
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        110 months ago

        Then you’ll have to deal with Lunar gravity, which may be unacceptable for long durations. Humans may have to live in giant space stations if we want to live in space. And since they can be truly massive, it may be more desirable than what some might think.

        • @morphballganon
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          110 months ago

          The ideal solution is probably not to build a colony in the middle of space, but rather find a celestial body with the necessary materials with gravity low enough to be acceptable.

          Moon gravity too strong? Try smaller moons. Phobos? Europa? Charon?