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If humans had access to artificial gravity technology similar to Star Trek in terms of holding people to the floor, and if faced with annihilation and forced to build a generation ship to escape Earth, would they use an O'Neil cylinder and use the rotational gravity or stack layers inside the cylinder and use the artificial gravity to stack everyone vertically from the top to the bottom of the cylinder?

The only choice they can go with is the one which allows for the maximum amount of usable space. (Which one can pack more humans in)

Bonus: If the O'Neil cylinder wins , what would be an incentive to use the vertical design instead

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    $\begingroup$ Insufficient data × 10. What factors are important to the builders, with what priorities and relative costs? Note that fake gravity is not real so we don’t know what properies it has—maybe it uses too much power or causes cancer? $\endgroup$ – JDługosz Jan 20 '17 at 0:32
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    $\begingroup$ Why could you not build a multi-level O'Neill cylinder? I mean, yes, the local gravity will be a little different on different levels ("gravity" = velocity^2/radius afterall), but as long as the diameter is much larger than the distance between the top and bottom levels, you'd hardly notice. Plus, it depends on how much supporting machinery the station needs, it you use the space in the middle of the O'Neill cylinder for housing all the life support, power generation, engines, water, food (zero-g farms), I'd imagine the two would work out similar. $\endgroup$ – Samwise Jan 20 '17 at 0:45
  • $\begingroup$ What you really must do is give us the dimensions of the ship. Height, radius, how high you want the ceilings. $\endgroup$ – AngelPray Jan 20 '17 at 0:45
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    $\begingroup$ While the "what would they choose?" part makes this question sound opinion-based, the "what allows the maximum amount of usable space" can be answered using mathematics - about as far from opinions as you can get. $\endgroup$ – Zxyrra Jan 20 '17 at 3:55
  • $\begingroup$ It all depends on the costs of both solutions and you didn't define them. I believe this makes good objective answers impossible. $\endgroup$ – Mołot Jan 20 '17 at 16:16
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In terms of bin packing, humans standing up can fully tile a 3D cylinder with floors. With them standing as tight as they can on shells, there is always lost space around the head. No matter the dimensions of the cylinder, the artificial gravity layers will always allow more humans to be packed in than shells will. Plain geometry.

[EDIT] In the picture below, you can see 8 humans, represented by the cylinders of space a human needs, arranged in two floors vs 8 humans arranged around a shell. The blue areas show the wasted space. You can change the red cylinder to be however much space you want to allocate per human -- make it as small as a pod or as big as a house. You can make the black cylinders as big or as small as you want them. Whatever size you make them, you will get more efficient use of space in a floor-by-floor arrangement than in a shell-by-shell arrangement. The amount of room available on the ground for things to stand around is the same as the ceiling room in the floor-by-floor model. It is vastly different in the shell-by-shell model, although it does get better the bigger the circumference of the shells.

enter image description here

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    $\begingroup$ You don't know that. OP never posted technical requirements of this tech. If it requires kilometers thick layers of machinery and dozens or hundreds kilometers of gaps to avoid interferences, then you're wrong. $\endgroup$ – Mołot Jan 20 '17 at 16:26
  • $\begingroup$ My answer deals purely with the geometry. If you say "I have a cylinder of X space," then people pack better with layers than with shells. The question simply asked which one can pack in more humans. @Molot $\endgroup$ – SRM - Reinstate Monica Jan 20 '17 at 20:36
  • $\begingroup$ Assuming there is no artificial gravity, and same text you have - there will be no changes in answer - artificial gravity affects literary nothing in your answer. Same about orientation, if artificial gravity exists, you can orient your layers, spiral around axis, just radial layers, or just flat layers perpendicular to axis - there is no difference in all those situations - AG do not make any of those solutions as preferable (with your arguments) because basically, we divide the volume by volume per human, and all those solutions allow us to have desired ceiling height. The A is not A. $\endgroup$ – MolbOrg Jan 20 '17 at 21:46
  • $\begingroup$ @MolbOrg I'll add pictures. No, you can't simply divide unless you're cutting arms off people and gluing them to ceilings. $\endgroup$ – SRM - Reinstate Monica Jan 20 '17 at 23:03
  • $\begingroup$ @SRM we both understand that is it approximation - yes? Also my typical pink invisible space habitat is few km in diameter, and usually they have at least few thousands cubic meters per human. Would like to pack them so dense that cutting arms and/or other parts of their body would be a problem, I would freeze them and stack in hope I have technology to unfreeze them back. Difference of two circles with 1000 and 1002m (radius) per segment is 0.2%, and for the segment 2 meter per human it will be shorter 4mm - not even close to need to cut a hair in the situation. $\endgroup$ – MolbOrg Jan 21 '17 at 1:43

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