Sheet 4 · Specifications
Specifications
Primary dimensions of the vessel, the stationary shield and the exterior systems, with the geometry and rotation figures derived from them.
Primary dimensions
| Parameter | Value | Note |
|---|---|---|
| Barrel length, L | 500 m | Habitable barrel, between dome springlines |
| Radius, r | 200 m | Hull inner surface; diameter 400 m, L : D = 5 : 4 |
| End domes | 50 m rise | Spherical caps, curvature radius 425 m; vessel 600 m overall |
| Rotation rate | 2.115 rpm | Exactly 1 g at the rim |
| Location | Earth–Moon L5 | Nonspinning bulk shield |
| Radiation shield | 410 m × 610 m | Stationary regolith enclosure, mean radius 205 m, flat end panels, 4,500 kg/m² |
| Hull | 125 mm Al-Li | Barrel skin 125.02 mm, dome skin 124.35 mm, installed |
| Soil | 0.30 m | Wet loam at 1,500 kg/m³ over Zones A and B |
| Atmosphere | 101.3 kPa, 20 °C | Sea-level pressure, pO₂ 21.2 kPa |
Derived geometry computed
| Quantity | Value | Formula | Note |
|---|---|---|---|
| Circumference, the walking loop | 1,256.6 m | 2πr | 1.26 km, about three laps of a 400 m track |
| Interior surface | 628,319 m² = 155.3 acres | 2πrL | Hull inner surface, barrel only |
| Interior versus Vatican City | 142% | 155.3 / 109 acres | The interior is larger than the Vatican |
| Zone A, Zone B area, each | 213,000 m² = 52.6 acres | 2πr × 169.5 | 169.5 m axial band each |
| Walking strip area | 202,319 m² = 50.0 acres | 2πr × 161 | 161 m axial band at the centre |
| Zone split | 52.6 / 50.0 / 52.6 acres | sum 155.3 | Zone A / strip / Zone B |
| Barrel volume | 62.832 × 10⁶ m³ | πr²L | — |
| Dome volume, both / vessel total | 6.414 / 69.246 × 10⁶ m³ | 2πh²(Rc − h/3) | — |
| Dome skin area, both / pressure area | 267,035 / 895,354 m² | 4πRc h | — |
| Shield enclosure area | 1,049,763 m² | 2πRsLs + 2πRs² | — |
Rotation and gravity
| Quantity | Value | Formula | Note |
|---|---|---|---|
| Rotation for exactly 1 g | 2.115 rpm | √(g/r) · 60/2π | — |
| Angular velocity, ω | 0.2214 rad/s | √(g/r) | — |
| Period | 28.375 s | 2π/ω | — |
| Rim speed | 44.287 m/s | ωr | — |
| Rim acceleration | 9.80665 m/s² = 1.000 g | ω²r | — |
| Gravity gradient over a 2 m body | 1.0% | h / r | — |
| Coriolis at a 1.4 m/s walk | 0.62 m/s² = 6.3% g | 2ωv | — |
| Acceleration at r = 100 m | 4.903 m/s² = 0.500 g | ω²r | — |
| Acceleration at the axis | 0 | ω²·0 | — |
g = 9.80665 m/s². Gravity is linear in radius, 0.5% of g per metre. 2.1 rpm is at the upper edge of the commonly cited comfort threshold; most adapt within days, a minority need countermeasures. See M1-S-005.
Docking
| Feature | Value |
|---|---|
| Hubs | 2, despun, on the axis |
| Mounting | Stationary shield backbone, through the end panels |
| Hub / port diameter | 40–50 m / 80–100 m |
| Rim speed of a 40–50 m rotating hub | 4.43–5.54 m/s |
| Rim speed of an 80–100 m rotating port | 8.86–11.07 m/s |
| Transfer drum interface, r = 5 m | 1.107 m/s |
| Pressure thrust on a 10 m closure | 7.956 MN |
| Hub allowance in the mass ledger | 2 × 1,000 t |
A point on the axis is stationary, but any finite latch, seal or corridor at the hub of the spinning vessel moves at several metres per second. Craft therefore dock to despun hubs carried by the stationary shield; a pressure-isolated transfer drum spins up to rotor speed before its inner door opens. Transfer to the rim is a 200 m radial descent, gravity rising linearly from 0 to 1 g.
Sun line
| Parameter | Value |
|---|---|
| Length | 480 m |
| Diameter, with glow envelope | 25–30 m |
| Position | on axis |
| Light source | Piped sunlight, LED backup |
| Habitat illuminance target | 10,000 lux, 12 h/day |
| Collector area, habitat + crops | 33,667 + 28,935 m² |
Cardinal markers on the stationary shield
| Marker | Colour | Position |
|---|---|---|
| North | ■ red | 12 o'clock |
| East | ■ orange | 3 o'clock |
| South | ■ blue | 6 o'clock |
| West | ■ purple | 9 o'clock |
The stripes run the length of the shield with beacons on both end panels. Because the shield does not spin they are fixed navigation marks for approaching craft.
Exterior systems on the stationary shield
| System | Area | Mass | Note |
|---|---|---|---|
| Solar array, two wings | 119,601 m² | 221.4 t | 33.207 MW EOL at 277.6 W/m²; about 60,000 m² per wing, sun-facing |
| Radiators, 350 K, two-sided | 21,728 m² | 260.7 t | Edge-on to the sun; carry the whole 25.458 MW load |
| Sunlight collection optics | 62,602 m² | 313.0 t | Feeds the sun line; excludes pointing and baffle structure |
| Contingency storage, 1 h | — | 188.6 t | 28.29 MWh at 150 Wh/kg |
Site implementation
Plain HTML, CSS and ES modules; no build step and no network requests. The cutaway uses three.js r181 (vendored) with a WebGLRenderer, antialiasing and preserveDrawingBuffer. The stationary shield, hubs, wings, radiators and collector sit in a fixed group; the vessel and its interior spin in another. Interior population is instanced: trees, buildings and people (1.8 m capsules) are single draw calls each. The removed 125° sector is a world-fixed pair of clipping planes, so the habitat rotates beneath a stationary cut. The hull and soil section lines are drawn thicker than true scale so they remain visible from the default distance.