
O’Neill Cylinder
That’s O’Neill, with two ‘L’s!
– Stargate
Designed by Gerard O’Neill. The original concept consists of cylinder pairs, 32km long & 6.5km in diameter. Three land masses stretch lengthwise on the interior, spaced between 3 windows. Lined up with each window is a solar reflector, or mirror. Distributing the daylight evenly into the cylinder, this can be rotated to match the sun, and creating day/night cycles by opening and closing the mirrors.
Agriculture is handled by a large ring structure, divided into modules. These automated modules allow for distinct growing environments, gravity, etc. Additionally they can be swapped out and replaced with non-agriculture modules, or upgrades.
Transportation in O’Neill’s original paper called for engineless cable car’s. This is an efficient, engineless method, and has very low material & weight requirements. Modern technology allows for additional transportation methods such as small electric vehicles & maglev trains.
Entering and exiting the artificial gravity well can be done at the far end from the agriculture modules. A non-rotating cylinder allows for 0g docking, and a spin transfer elevator carries cargo between the docking ring and the primary cylinder.
O’Neill Cylinder – Statistics
| Length: 32 km | |
| Diameter: 6.5 km | |
| Livable Area: 150,000 km2 | |
| Gravity: 1G |


