I am trying to work out the size and (because this is among other things for populating a rotating habitat) weight of an arcology made to house, say, 5000 people - that seems a good number for a self-sufficient colony, large enough that you can avoid people you dislike, but small enough to still have a strong sense of community.

I assume you would (for civilian use) probably be able to get away with 20 m2 of personal habitation space per person - this is a room four meters by five meters, and while that is on the small side, it should be large enough not to feel cramped (source: My student apartment was about that big for a single person), so that gives 100,000 m2 for personal space. What I am a bit more lost on is how much space you'd have to allocate for workspaces and public space (I'd assume a few times as much as you have habitation space total, maybe 500,000 m2), hallways and elevator shafts (maybe on the same order as the amount of habitation space at most?) and also hydro-/aquaponics space to feed those 5000 people.

Assumptions I would be making for purposes of figuring out the size requirement of that and also the mass of the structure would be more or less near-future tech - meaning no bulk nanomaterials, but bulk availability of modern high-strength materials such as glass fibers or UHMWPE, and only mild genetic engineering of crops, as well as sufficient automation to run the aquaponics mostly automated, so that they can be run at the optimal environmental conditions for crop growth, without regards to human comfort.

The structure should be able to obviously withstand its own weight under 1 g of gravity, assuming a height of ~100 storeys, as well as (for use on Earth) moderate wind and seismic loads.

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    $\begingroup$ Does your personal space include washroom space? $\endgroup$ Feb 19, 2018 at 18:26
  • $\begingroup$ Oh, true, I didn't consider that - that would add a few more square meters to a single-person unit, but of course not grow as fast as the main habitation space - a three or four-person unit could I think still deal with only few square meters of washroom space, especially if you only have a shower and not a bathtub. $\endgroup$
    – Zuthal
    Feb 19, 2018 at 18:32
  • $\begingroup$ "hallways and elevator shafts" are unanswerable without knowing geometry you plan to use,size of parts etc you need to move around etc. Also, how long you want them to live there? $\endgroup$
    – Mołot
    Feb 19, 2018 at 18:45
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    $\begingroup$ This might help - 192 pages [Optimal Conceptual Design of High-Rise Office Buildings ](collectionscanada.gc.ca/obj/s4/f2/dsk3/ftp04/NQ60544.pdf) $\endgroup$ Feb 19, 2018 at 18:52
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    $\begingroup$ Does all food production happen within the building? Is the water supply limited? Is there space for water and sewage treatment? Is there (lots of) space for trash disposal? Is there space for theaters and sport and recreation? Are there dim nooks for teenagers to hide together and smoke? $\endgroup$
    – user535733
    Feb 19, 2018 at 20:18

1 Answer 1


100,000 tons

I spent two years in an arcology designed to house 5,000 people.

enter image description here

This arcology has many advantages. It has has its own nuclear reactors (two!) to provide power. It can move itself anywhere on the Earth's surface, as long as its wet. It comes with its own vehicles to trade supplies with the outside. The reactors provide plenty of energy for hydroponics, and there is an 80,000 cubic meter industrial space that is currently underutilized, just waiting for hydroponics installation.

enter image description here

Besides it has a 18,000 square meters of surface area on the top to plant, if necessary; although you can't do as much trading that way. It makes its own fresh water, has its own computer and communications infrastructure, and as a final bonus, it can also carry a lot of bombs, if you are into that.

Total mass of this arcology is about 100,000 tons; it is about 350 meters long, up to 80 meters wide, and about 60 meters top to bottom, although you can trim some of the antennas off if you want.

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    $\begingroup$ Can't top that answer, so I won't even try. $\endgroup$
    – Dan Clarke
    Feb 20, 2018 at 2:34
  • $\begingroup$ +1 for the navy! --- out of curiosity, if they wanted to, could they also have cattle, or any kind of edible vertebrates that they breed aboard? $\endgroup$
    – NofP
    Feb 20, 2018 at 8:17
  • $\begingroup$ @NofP Chickens are probably more reasonable for protein returns per unit volume, but I don't see why not. $\endgroup$
    – kingledion
    Feb 20, 2018 at 11:50

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