# Are space stations like Sevastopol (Alien Isolation) realistic?

Like this:

If we were to build stations in deep space meant exclusively for human habitation, would chunky floating cities like this be a feasible design or would we be more likely to create something like an O'Neill cylinder instead?

The major problem with building a space station like a city is that you can't really make it anything like Earth:

• O'Neill cylinders are big enough that they can have their own weather systems. The only way you can do this in a city-like space station is to create a giant dome encasing the entire thing, which seems to be something of a waste and makes it hard to exit the bloody thing on the top.
• O'Neill cylinders rotate, and so at a radius $r$ on a station rotating at $\omega$, the acceleration is $$a=-\omega^2r$$ You can do the same thing in a city-like station, but each tower would need to rotate on an axis from top to bottom, the gravity would attract people to the tower's walls, and it would need to rotate much quicker, given that its $r$ would be comparatively tiny (You could have the entire city rotate around an axis on its base, but the gravity won't be uniform everywhere.). Oh, and moving from one building to another would be tough, even if you entered from the bottom.
• It's easier to grow plants in an O'Neill cylinder unless you want to enlarge the dome over the city to include fields; there's plenty of room. Assuming you can't have fields in the domed city (which would be in areas without gravity, I think, and so would have weird conditions), you need to use hydroponics or turn skyscrapers into farms - again, without artificial gravity, since you'd have to have the towers rotating if you wanted uniform gravity. This could have negative effects on plants (I think the jury is out on that one). Animals might also behave differently, as bone density would be affected, but hey, perhaps we can just 3D print food. Tofurkey, anyone?
• And finally, yes, people like cities, but I think long-term inhabitants would want to remember the natural beauty of Earth, walking in meadows and hiking along trails (and maybe swimming in lakes). Can your floating cities do that.

For these reasons (and likely more), things will be much more convenient (gravity, weather, plants and animals, etc.) in an O'Neill cylinder that in a floating cylinder.

The benifit of the O'Neill cylinder is that you can get spin gravity by rotating it.

The Alien universe has artificial gravity, so space stations can be more like the one in the picture without having to float everywhere.

If your universe has artificial gravity then you can make the station look like anything you want. If not then you either have to spin or float.

The rule that form follows function is very true, and the function of the station will determine its shape.

Gravity? Ore processing? Farming? Residential areas?

Each of these will shape the final product.

It looks structurally unsound to me. Too much stress on the cross members, difficult to see where the center of gravity is, annoying to go from one tower to the other. Consider that the different ends of the station are in (slightly) different orbits. This causes them to want to move closer or move apart, imposing structural stresses. This occurs even on the ISS, causing it to creak and flex.

A space station of Sevastopols size would probably be approximately spherical, to get the maximum volume and structural strength from the minimum of materials. Plus curves hold in the pressure better than sharp angles. If the station will spin, to provide artifical gravity, then a cylinder shape is better, putting living areas on the outside, with the central, micro-g environment given over to docking ports and logistics.

It depends on what you're doing for gravity, if you have artificial gravity you can just about build whatever the hell you like and out it wherever you want to. If you're using "spin gravity" then your design choices are pretty much, sphere inefficient but workable, cylinder very efficient of space and materials, and cone for when you want your "gravity" to vary according to location.