Editing O'Neill Habitat Ring Seven (section)

== Overview ==

Ring Seven comprised two counter-rotating cylinders, each approximately 6.4 kilometres in length and 1.6 kilometres in radius, coupled by a central docking collar and bearing hub. Counter-rotation neutralized net angular momentum, preventing attitude drift without continuous thruster expenditure. Interior surfaces were divided into alternating land strips and window strips, the latter admitting redirected solar illumination through an articulated mirror array mounted along each cylinder's long axis.

The six supplementary deuterium fusion cells, installed during the 2197 refit following the Prometheus Foundry Strike settlement, provided emergency power during mirror-occultation events and sustained life-support systems independent of solar input for up to fourteen days. Agricultural sleeve modules — short pressurized drums attached radially at the cylinder midpoints — extended Ring Seven's food production capacity beyond any predecessor station in the L5 cluster.

At its operational peak in the 2240s CE, Ring Seven housed administrative offices of the Ceres Charter Compact, berthing facilities for [[Helios-3 Cyclers]] on the Mars–Luna run, fabrication bays operated by the Lunagineering Consortium, and a residential population drawn from [[First Sustained Mars Surface Missions|Mars settlers']] descendants, belt-transit workers, and Lunar emigrants alike.

=== Key Specifications ===

{| class="wikitable"
|-
! Parameter !! Specification
|-
| Cylinder length || 6.4 km per cylinder (×2)
|-
| Cylinder radius || 1.6 km
|-
| Interior surface area || ~128 km² (combined, usable)
|-
| Rotational period || 114 seconds (1 g equivalent at rim)
|-
| Peak residential population || ~84,000 (c. 2244 CE)
|-
| Agricultural sleeve modules || 8 (added progressively 2191–2210 CE)
|-
| Primary power || Solar mirror array (~2.4 GW equivalent)
|-
| Backup power || 6 × deuterium fusion cells (~180 MW combined)
|-
| Docking berths || 42 standard; 6 heavy-lift collars
|-
| Operational lifespan || 119 years (2191–2310 CE)
|}