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.
- 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.
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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?
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How might carbon get utilized for large structure fabrication in space as far as processes?
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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.
The materials have been shown and proven in theory. It is simply a matter of building the space based manufacturing and infrastructure required. This is like Romans talking about what it will take to build nuclear power plants if they could somehow imagine them. I laid out the economy scale that I am talking about at the outset. This is an order of magnitude, or more, larger total human economic output. An era when this construction scale is not very novel.
If we are colonizing the rest of the Solar system, we figured out large scale and pressure vessels already. Once we are building in space with materials sourced from space, most of the problems go away.
Worst case, a ship can use nuclear detonations to both accelerate and decelerate easily within the limits of known materials. This has been thoroughly researched in a US program that was only canned as part of anti nuclear proliferation act. This system can easily handle both ends and traveling faster than any current method. It is a worst case. If we can master fusion, there are other ways as well.
I said generation ships too. I don’t care if it is slow and I think humans could cope just fine on a large enough ship, assuming we don’t find ways to put humans on ice.
I highly recommend checking out Isaac Arthur’s content on YT as he goes though all of this kind of stuff in detail but even further into possibility and future tech. I’m getting much more specific into a time and constraints than what IA does in general.
No. This is an assumption not borne of physics or engineering. There is no magic material that will make large scale pressure vessels suddenly viable. It (and space elevators) are mathematical constructs, not real things.
Use this calculator. https://checalc.com/calc/vesselThick.html – punch in 15 psi for pressure, and 100F for temperature. Play with your pressure vessel. Wall thickness of large scale habitats will need to be many metres of solid steel (or equivalent material). Even if you magically mass produce carbon nanotubes or something, you still need hundreds of millions of tonnes of carbon to pull off any large scale vessel. Your talking about ingesting entire asteroids just for building materials. You don’t launch that shit on an interstellar journey.