Inside the habitat

[Drashner1]

Re the issue of how long it took to move from small habs to larger ones - a factor in this would almost certainly be a certain amount of learning curve when the current RL theoretical designs (or more likely some future descendant of them) start actually being built (or people attempt to build them anyway).

Without doubt there will be some amount of design flaws, unexpected/unplanned effects from being in a space environment (both on the structure and on the people building and/or living in it), etc. All of these sorts of factors will work to slow down hab construction and evolution. OTOH there will also almost certainly be some number of currently unknown/unforeseen positive results (design innovations, new tech, taking advantage of some element(s) of the space environment) that mitigate the problems or even accelerate some aspects of space development. Logistics and raw materials are also both going to have an impact. We touch a little on early asteorid mining but don't get into it much, but presumably at some point it would supplant Earth provided resources. It would also go thru a similar positives vs negatives of space dev process which would impact the speed of advancement too.

We're an SF project, not a research lab so not suggesting we need to actively try to figure out the details of this kind of stuff. But we could at the least use it as a reason or meta-reason for it taking a bit longer for larger habs to get built.

Re the issues of density and food production - We mention elsewhere in the context of Earth that higher density food growing is developed in cities and such. That same tech could have application in early (or even Y11k) habs and could itself take lessons from the development of space based food production (creating a feedback loop that could benefit both fields). Incidentally, this is an area that neither we nor anyone else (AFAIK) has explored in any depth. Possibly an aspect of the setting to dive into at some point.

Re population density - being 3D structures, space hab could potentially host very high density populations while still leaving room for some amount of green space (the development of Earth based arcologies could impact this and/or the dev of space based high density living could impact arcology development back on Earth). On the flip side, it's also possible (even likely?) that there are biological/psychological limits on how well a general population of humans can handle living in an enclosed space for an extended period that will impact how small or enclosed a space hab can be if it is to be used as a home rather than a temporary worksite. Not everyone is cut out to crew a nuclear submarine and living on an oil rig for months vs living there with no plans to ever leave could be two very different things (as it were).

Not sure if there are RL resources that get into human limits/health in this area, or if we want to get that deep into the weeds on this, but it might be possible to locate some and use it to at least partly inform this aspect of things. Or we could just keep these kind of factors in mind and aim for a consensus on what we consider plausible in this area and move forward from there.

Todd

[Rynn]

I suspect that some of the smaller, earlier ones were quite densely populated. An 'urban' cylinder with lots of layers and lots of habitable space could support a large population, although they might feel a bit cramped. I know I would suffer from claustrophobia in a crowded hab.

People are very adaptable. Tens of millions of people IRL live in dense cities and find it completely fine. To the point that cultural ideas of what a constitutes a large vs small home can be quite different. More dense population also allows for a concentration of services and economy which would be necessary for earlier habs.

Also a crowded urban habitat would need to import food or manufacture it from recycled materials within the hab. But you might get used to it, especially with sophisticated design and social engineering.

With vertical farming, aquaculture, automated polyculture etc. food really shouldn't be a problem. You could have entire decks that are sub-divided into spaces too small for people to walk through upright in order to maximise your growing space

A rural design could grow at least some of its food agriculturally, although I suspect most of the interior would be used for recreational purposes rather than food production. O'Neill's original design incorporated a series of external food production units, collecting sunlight for plant growth in greenhouse habs; a rural habitat would have a lower population, but would still probably need external greenhouse habs to supplement the food supply.

I expect larger environments would be a recreational choice, though another reason might be a desire for a more complex ecosystem. I've no doubt a smaller, denser hab could look very green but the ecosystem would probably be minimally viable in terms of complexity. Something like the Kalpana One concept design.

[Worldtree]

also, despite the fact that a much more enclosed and dense urban planning design is probably a better idea for habitat interiors, I'm pretty sure most of the renderings use these huge open spaces and agricultural areas with immense amounts of unused air space because it's more dramatic, and shows the spin gravity and landscape better , rather than a series of slightly curved hallways and large rooms.

[stevebowers]

If a multi-layered, densely populated habitat also grew a significant fraction of its food, this would require a very large energy through-put; a lot of solar power collection, and large radiators to eject the waste heat. It could be done, but the result would look a bit different to the basic cylinders we've been depicting so far.

I note that the Stanford Torus (designed by a group that was independent of O'Neill's studies) did include a large light-collection system as well as a prominent radiator pointing directly away from the Sun.

[Rynn]

Indeed. In terms of energy there would likely be very long solar petals coming off of a hab. Potentially many times the radius of the torus/cylinder itself. Of course they could always go heavy on fusion, and might need to if they’re in the outer system.