Building your O'Neill Cylinder

[robject]

Ecological Niche: Between the Stanford Torus and Ringworlds.
Size: 32 km length
Volume: 59 to 236 billion tons per pair.
Population Digit: 6.

O'Neill Cylinders are built in pairs, with an 8 km diameter, and up to 32 km in length, so presumably 8 km to 32 km in length. An outer ring 32 km in diameter is used for agriculture, so the 'size' of these cylinders is always 32 km.

Half of the internal surface area is living space. Half is transparent.

Since the radius is 4 km, the base area of the cylinders are pi x r^2 = about 50 million m^2.

Volumes for pairs of cylinders range from 50,000,000 x 8,000 x 2 = 59 billion tons (larger than the Loeskalth planetoid), to 50,000,000 x 32,000 x 2 = 236 billion tons.

Living space is purportedly for "millions". Surface area in a pair of 32 km cylinders is 4,000 m x 32,000 m = 128 square km. Presumably all of it is living space (agriculture being housed in the outer ring), and buildings can be quite tall (since the center point of the cylinder is 4 km up, AND "gravity" decreases as buildings approach this point). So a lot of that volume is usable.

Orbital Fort No. 6 is a variant of the O'Neill Cylinder, 10 km diameter, 30 km long, a 1 km "wall", and the center open to space. The wall contains everything -- habitat, workspace, etc. The center is for servicing a fleet.




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[kilemall]

O'Neills are basically 'Earth' IMTU, Earth itself is an Amber Zone plague/heritage remnants/nursery/genetic preserve.

They were built after Earth's population was drastically cut by The Great Plague to house the majority of the survivors. They are referred to as Cities, roughly corresponding to one per major pre-plague metropolitan area.

There are approximately 1500 built, with just a few losses over the years.

Their construction was from lunar regolith leftover after the He-3 mining boom, shot up into lagrange points, melted down and poured into interlocking beam forms by solar foundries. As such, they are 'bulkier' and not as space efficient as a metal/synth-based station, more akin to an artificial hollowed out asteroid form then anything else.

They are not movable, once built they pretty much stay in place.

They do not have the direct solar openings, due to the scale of the project, the need to keep costs down, and the absolute need to be able to weather any and all solar storms and prevent irradiation of the interior and it's occupants. Instead, a solotube setup with light diffusing from a tube that runs down the center axis serves as light source.

Extensive solar arrays are mounted on the outside along with emergency reactors.

Centrifugal rotation provides 'gravity' for everything except buildings that approach the center in height- the whole thing is just too big for economical generated gravity. It follows that interruption of the rotation would be disastrous. Solar sails have been attempted to start rotation, but ended up not being practical, low impulse ion engines were used to start the spin up.

Had not considered a double hull/agriculture setup, but that makes sense both from an efficient use of space and increased protection against radiation/impacts.

 

[Jeff M. Hopper]

Ecological Niche: Between the Stanford Torus and Ringworlds.
Size: 32 km length
Volume: 59 to 236 billion tons per pair.
Population Digit: 6.

O'Neill Cylinders are built in pairs, with an 8 km diameter, and up to 32 km in length, so presumably 8 km to 32 km in length. An outer ring 32 km in diameter is used for agriculture, so the 'size' of these cylinders is always 32 km.

Half of the internal surface area is living space. Half is transparent.

Since the radius is 4 km, the base area of the cylinders are pi x r^2 = about 50 million m^2.

Volumes for pairs of cylinders range from 50,000,000 x 8,000 x 2 = 59 billion tons (larger than the Loeskalth planetoid), to 50,000,000 x 32,000 x 2 = 236 billion tons.

Living space is purportedly for "millions". Surface area in a pair of 32 km cylinders is 4,000 m x 32,000 m = 128 square km. Presumably all of it is living space (agriculture being housed in the outer ring), and buildings can be quite tall (since the center point of the cylinder is 4 km up, AND "gravity" decreases as buildings approach this point). So a lot of that volume is usable.

Orbital Fort No. 6 is a variant of the O'Neill Cylinder, 10 km diameter, 30 km long, a 1 km "wall", and the center open to space. The wall contains everything -- habitat, workspace, etc. The center is for servicing a fleet.




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You can do a variant O'Neill cylinder with two half-length cylinders placed butt-to-butt on a de-spin platform that doubles as the spaceport/industrial block. No mirrors, all light is provided by a fusion powered tube running down the center, so also no windows to rob you of surface area.