Concordia

Station map

A rotor's floor is the inside of a cylinder. Cut it along one street and lay it flat and you get a strip 15.7 km long and 2.5 km wide, and its left and right edges are the same street. This page maps all of Concordia that way, with a pin for every view you can open in the simulation.

The whole station

Concordia is 21 km long. Four city rotors sit aft, Ehricke (the industrial rotor) in the middle, the shipyard and the spaceport forward. Tsiolkovsky (Rotor 1) and Noordung (Rotor 2) turn one way and Bernal (Rotor 3) and O'Neill (Rotor 4) the other, so the pairs cancel each other's angular momentum. Select a rotor to jump to its plan, or a pin to preview a view.

Concordia seen from the side along its 21 km axis Side view to scale from the aft end at minus 10.5 km to the propellant farm at about plus 12 km. From aft: aft works, Tsiolkovsky and Noordung (Rotors 1 and 2) turning one way, Bernal and O'Neill (Rotors 3 and 4) turning the other, the momentum bay, Ehricke (the industrial rotor) in an open bay, the shipyard cage with a ship floating above the spine, the spaceport and piers, and the propellant farm beyond. A stationary spine runs down the middle and the launch track runs along the top between minus 5 and plus 5 km. Arrows show which way the near surface of each rotor moves. Each part links to its map section or place page. {"kind":"side-view","mapLinks":true,"generator":"a51fa8fd11a9","source":{"hullR":3100,"rotorCenters":[-7800,-5000,-2200,600],"zones":{"momentumBay":[1850,2750],"industrial":[2750,6250],"shipyard":[6250,9400],"rotorHalfLength":1250}}} 1Tsiolkovsky 2Noordung 3Bernal 4O'Neill Ehricke Aft works Rotors 1 to 4: four cities at 1 g Industrial rotor Shipyard cage Spaceport Launch track, 10 km Stationary spine, 120 m wide Momentum bay Propellant farm -10 km-5 km0 km+5 km+10 km ← 6→ 3↑ 5
Aft is on the left. Each part of the station links to its section or place page; each pin opens a view in the simulation.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

Views along the axis (30)
  1. Converter hall InfrastructureThrough arched windows of the spine: rows of HVDC valve halls, breaker bays, capacitor banks and cooling headers. This is where solar power becomes city power.On the scenes page
  2. Inside the spine Ground to AxisA 120 m tube that never turns, with ring lamps every 25 m, the express guideway on its stays, crew galleries and four utility trunks running its length.On the scenes page
  3. Spin-decoupling lock Ground to AxisInside the spine at the Rotor 1 hub, a carousel of eight chambers slows each carriage from rotor speed to rest in 96 seconds. An amber ring and a spin-rate display show the progress.On the scenes page
  4. Dish station ExteriorA 170 m dish on its lattice tower, with an equipment hut, an optical terminal and phased arrays. Optical links carry most of the traffic.On the scenes page
  5. Inter-rotor bridge from outside Ground to AxisA transit bridge joins Rotors 1 and 2, 45 m above the ground. X bracing, window bands and a lenticular truss carry people over the vacuum.On the scenes page
  6. On the bridge deck Ground to AxisA promenade and a transit lane run side by side, with window bands on both sides and a shuttle on its guideway. The far pressure door marks the next rotor.On the scenes page
  7. The gap between rotors Ground to AxisA 300 m vacuum gap separates the rotors. Rotor ends, bearings and service connections are all exposed here.On the scenes page
  8. Launcher cabin SpaceportThe 98-couch passenger cabin, seen from the starboard aisle. A window band and aisle lighting run its length, with a shelter bulkhead behind.On the scenes page
  9. Counter-rotating interface Ground to AxisRotors 2 and 3 turn opposite ways, so there is no bridge between them. A stationary service frame and slip seals fill the gap, and passengers cross through the spine.On the scenes page
  10. Launcher track SpaceportA 10 km electromagnetic track and its gantries along the hull. This is the road that sends passengers away from the station at 1.5 g.On the scenes page
  11. Radiator field ExteriorA bank of radiators on pylons rises above the hull. Each panel is 400 by 200 m and turns slowly with the Sun.On the scenes page
  12. Inside the express Ground to AxisA car on the spine express, with restraint couches along the wall, grab rails, lockers and a destination display above the open end door.On the scenes page
  13. The express on its guideway Ground to AxisFive cars in a row run the spine at 140 m/s on levitation bogies. The cab nose carries a destination board and running lights.On the scenes page
  14. Momentum control bay InfrastructureRing machines spin in their housings in the stationary bay. They hold the station's net spin at zero by trading momentum with the rotors.On the scenes page
  15. Momentum ring close up InfrastructureUnder ring 2: containment housing, motor-generator stators, bearing stacks and coolant loops, with the rim turning in the open side.On the scenes page
  16. Industrial rotor from outside ExteriorAn open-vacuum bay in the shell exposes the industrial rotor turning inside.On the scenes page
  17. Open pressure section InfrastructureThe open crew drum of a ship under construction, showing its deck stack, capture arms, a manipulator and an inspection capsule at working range.On the scenes page
  18. Shipyard through the cage ExteriorLooking in from the shade side through the open forward cage, past yard ribs and frames to the hero ship.On the scenes page
  19. The zero-g shipyard InfrastructureA spacecraft floats unsupported inside a construction volume much larger than itself. There is no floor, so frames, tanks and tugs hold it from all sides.On the scenes page
  20. Tank bay InfrastructureA tank on approach with its mover, held by tension lines, with crawlers and umbilicals around the cradles. The ship's propellant is built and fitted here.On the scenes page
  21. Arrival face SpaceportPassengers float down the processing ranks of health screening, customs and security, toward the WELCOME TO CONCORDIA sign over the entrance.On the scenes page
  22. Spaceport terminal SpaceportThe arrival hall of the port, in stationary zero g. Signage, public structure and docking views make up the first look at Concordia for visiting passengers.On the scenes page
  23. Concourse A SpaceportAn open concourse with glide rails, travellers, shop pods and gate pods along the glass wall under a zone arch.On the scenes page
  24. Gate A03 SpaceportA boarding bridge, a berth frame and a docked passenger craft, seen from the axial bay. Gates A01 to A05 open off the nave.On the scenes page
  25. Rotating lounges SpaceportThree slow wheels turn at 2 rpm, giving 0.13, 0.20 and 0.28 g. They are a gentle step between zero g and the full weight of the cities.On the scenes page
  26. Forward defence battery ExteriorAn armoured housing with a reload magazine, interceptor cells, a net launcher and a Whipple skirt guards the forward end against debris.On the scenes page
  27. External pier SpaceportPier P1 on the outer face of the end bulkhead, with a freighter alongside, tugs working and the axial aperture beyond.On the scenes page

From drum to map

The plan on the drum wall and the flat map below are the same drawing. Lengths along the floor never change as it unrolls, so a lake keeps its shape and every pin keeps its place. Scroll through the animation or press play.

Three frames of Tsiolkovsky (Rotor 1): the drum with the city on its inner wall, the floor cut and half unrolled, and the flat map.
Each rotor is a city on the inside of a drum. Cut the floor along one street and lay it flat and you have the map below. Scroll to play it, or use the controls.
Go deeper: Unrolling a cylinder

A floor point at arc length s from the cut, on a rotor of radius R = 2,500 m, bends with unroll progress t from 0 (the drum) to 1 (flat). The curvature is k = (1 - t) / R.

x = sin(k s) / k
z = (1 - cos(k s)) / k

At t = 1 the curvature is zero and the point sits at (s, 0), so the circumference 2 π R = 15,708 m becomes the width of the map. Up is toward the axis, because gravity points outward: a pin at 625 m stands a quarter of the way in, where the weight is 0.75 g. The stalks in the animation stay perpendicular to the floor all the way down.

A habitation rotor turns once every 100 seconds, in the sense given by its spin pair. The industrial rotor has no floor, so its three gravity bands unroll as three separate cylinders of different radius: the strips come apart, and their different widths are the point.

The rotors

Each rotor is generated from its own seed, with 72 to 114 lakes, about 40 districts and 30 to 35 percent of its floor given to parks, lakes and plazas. Pick one. Zoom in to read a single park, and pins close together gather into a count.

Tsiolkovsky Rotor 1

Tsiolkovsky was the first rotor to be spun up, and the first residents arrived in 2041. The Arbor Quarter, home of the story family, sits at the left edge of the plan, where the cut runs straight down its main street. The rotor turns retrograde, seen from the spaceport end, and is paired with Noordung through rotating bridges. Parks, lakes and plazas cover 32 percent of its floor.

A quiet residential street of mid-rise blocks lined with trees, with the curved city rising ahead under a bright artificial sky.
Tsiolkovsky: the main street of the Arbor Quarter, the street the plan is cut along. Open this view
Unrolled ground plan of Tsiolkovsky (Rotor 1): districts, parks, lakes, streets, metro and landmarks, 15.7 km around by 2.5 km along the axis. The left and right edges are the same street.
Tsiolkovsky (Rotor 1): forward is up, the aft end wall at the bottom. A pin with a ring is above the 150 m level; its colour is the gravity band.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

What is drawn

  • Mid-rise residential
  • Premium residential
  • Civic and parkland
  • Lake park
  • Urban core
  • Vertical residential
  • Axis access
  • Service
  • Park
  • Lake
  • Plaza
  • Ring, spoke and boulevard streets
  • Arterial and collector streets
  • Metro
  • Axis station (ascender tower)
  • Landmark tower

Views in Tsiolkovsky

  1. A residential street at ground level, 1.0 gAn ordinary street in Tsiolkovsky (Rotor 1) at eye height. The ground is the rotor wall, so it feels like any street on Earth, and the lawns and buildings run on until they curve out of sight.On the scenes page
  2. Metro lift tower at ground level, 1.0 gA glass lift tower at the Arbor crossing, with a street door and canopy at the foot and a shaft rising 46 m to the platform deck.On the scenes page
  3. A park by the lake at ground level, 1.0 gA lakeside park a short walk from the family apartment, framed by low-rise housing. The path leads to the water, and the far shore bends upward with the rest of the city.On the scenes page
  4. Viaduct over the avenue at ground level, 1.0 gFrom the street, the metro runs 45 m overhead on portal piers and carries on along the avenue. The line stays above so the street stays free.On the scenes page
  5. District skyline at ground level, 1.0 gCrowned towers, spires and one signature landmark seen from a park lawn 1.1 km away. Every skyline here is a cluster of landmarks set against the curve of the world.On the scenes page
  6. Axis Station plaza at ground level, 1.0 gThe plaza at the foot of the ascender, where the metro delivers commuters. The boarding lift entrance is the doorway to the sky and the axis above it.On the scenes page
  7. Foot of the end wall at ground level, 1.0 gThe end bay of Rotor 1 at the foot of its forward wall. Cantilevered ledges with coffered undersides step up, a train viaduct crosses the frame and a planted cliff rises to the sky seam.On the scenes page
  8. Arbor metro platform at 57 m, 0.98 gThe 108 m platform on its hump at 55 m, with screen doors, a canopy and a train set waiting. This is the Arbor interchange.On the scenes page
  9. Foot of the megaframe at 75 m, 0.97 gA rib of the megaframe rises from a lived-in neighborhood. This lattice carries the elevated city up to 1,500 m on the wall of the rotor.On the scenes page
  10. Viaduct terrace on the end wall at 250 m, 0.90 gA 241 m ledge on the forward end wall, at about 0.9 g. A train runs along the track strip, vines trail from the planters and the city lies 240 m below.On the scenes page
  11. Ascender at 250 m at 250 m, 0.90 gEarly in the climb the neighborhood is still familiar, and the horizon begins to rise around the cabin. Weight has already dropped to about 0.90 g.On the scenes page
  12. Inside the ascender cabin at 650 m, 0.74 gThe panoramic cabin at 650 m, where weight is 0.74 g. Seats, rails and a glass floor gallery face the city curving up beyond the glass, with a live altitude and gravity readout.On the scenes page
  13. A plate district at 625 m at 690 m, 0.72 gA raised quarter at 625 m, where weight is about 0.75 g. Planters line the deck edge, an inhabited bridge crosses the ring beam and, above the sky layer, the opposite upper city hangs overhead.On the scenes page
  14. Through the artificial sky at 800 m, 0.68 gThe cabin passes the sky layer and the blue ceiling becomes a lit machine, with the opposite city overhead and the open interior beyond.On the scenes page
  15. Ascender tower from outside at 810 m, 0.68 gFour blade trusses with bronze lattice rise past 800 m. Three tracks carry cabins up and down, with the axis far above.On the scenes page
  16. Packaging and dispatch at 1,000 m, 0.60 gCrates of salad, trays of loaves, bottles and wrapped pallets leave the process wing on freight pods. Ordinary food, moving the way ordinary food does.On the scenes page
  17. Harvest line at 1,000 m, 0.60 gTotes arrive on a belt and pass the wash tunnel, the optical sorter and the weigher in the process wing. Most of what grows upstairs is on a city table soon after.On the scenes page
  18. Grow deck at 1,030 m, 0.59 gA visitor gallery above a deck of the farm hall. Racks of lettuce, basil and kale stand in four stages of growth beneath LED rigs, with nutrient channels and a harvest gantry.On the scenes page
  19. Service facilities at 1,000 m at 1,270 m, 0.49 gA grow gallery and a utility plant of the 1,000 m service tier, seen from the open fringe. Glazed rack faces glow white and magenta beside vessels, air handlers and pipe racks.On the scenes page
  20. Low-gravity atrium at 1,700 m, 0.32 gHigh in the frame, near 0.32 g, long-span structure opens into sparse atmospheric process halls. Everything is lighter here, including the way people move through it.On the scenes page
  21. City turning around the viewer at 2,130 m, 0.15 gStand on the spine and the city turns around you, once every 100 seconds. The spine is the only thing that holds still.On the scenes page
  22. Rotating transfer hub at 2,140 m, 0.14 gThe hub drum turns behind its bearing collar, with four portals marked by bronze sunbursts. This is where the ascender cabins meet the stationary spine.On the scenes page
  23. Upper end wall from the axis side at 2,150 m, 0.14 gThe upper end wall seen from about 2,150 m, at 0.14 g. Concentric ledge rings carry low-gravity halls, vaults and gardens, and the ribs thin toward the bore.On the scenes page

Noordung Rotor 2

Noordung turns the same way as Tsiolkovsky and is locked in step with it. Its forward end wall faces Bernal's aft wall across the counter-rotating interface, where the two walls pass each other at about 313 m/s, so no bridge crosses that gap. Its sky runs a 14 hour day, the longest on the station.

Copper-crowned towers and spires seen from above, with megaframe ribs and the far side of the curved world beyond.
Noordung from 120 m up: copper-crowned towers and spires at arm's length, the megaframe and the far side of the world beyond. Open this view
Unrolled ground plan of Noordung (Rotor 2): districts, parks, lakes, streets, metro and landmarks, 15.7 km around by 2.5 km along the axis. The left and right edges are the same street.
Noordung (Rotor 2): forward is up, the aft end wall at the bottom. A pin with a ring is above the 150 m level; its colour is the gravity band.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

What is drawn

  • Mid-rise residential
  • Premium residential
  • Civic and parkland
  • Lake park
  • Urban core
  • Vertical residential
  • Axis access
  • Service
  • Park
  • Lake
  • Plaza
  • Ring, spoke and boulevard streets
  • Arterial and collector streets
  • Metro
  • Axis station (ascender tower)
  • Landmark tower

Views in Noordung

  1. A civic street in Noordung at ground level, 1.0 gA paved street in Noordung (Rotor 2) with a stately civic frontage on one side and a green square ahead. Beyond the square a tower district climbs the curve of the rotor. The generator that drew Tsiolkovsky drew a different city here, from its own seed.On the scenes page
  2. Charter Hall at ground level, 1.0 gThe seat of the Concordia Charter Authority, seen from the street in front of its portico. Gate towers and a vaulted roof stand over the colonnade in the densest core on the station.On the scenes page
  3. The Court at ground level, 1.0 gA columned portico and pediment on a street of civic frontages in Noordung. The arbitration courts sit here, in the same quarter as the Exchange and Charter Hall.On the scenes page
  4. Lakeshore in Noordung at ground level, 1.0 gA promenade on the shore of one of Noordung's lakes. The reeds are planted, the path is paved and the ground climbs away along the ring to a bright sky. Noordung runs a 14 hour day, the longest on the station.On the scenes page
  5. The Exchange in Noordung at ground level, 1.0 gThe market hall of the capital quarter in Noordung (Rotor 2), a dome behind a portico on its own plaza. Energy and compute for the whole station are priced here, a few streets from the Charter Hall and the Court.On the scenes page
  6. Crowned towers at 120 m at 120 m, 0.95 gCopper-crowned towers and spires in Noordung from 120 m up, where the weight is about 0.95 g. Megaframe ribs rise between them and the ground climbs away along the ring in every direction.On the scenes page

Bernal Rotor 3

Bernal turns the opposite way from the first two rotors, prograde seen from the spaceport end, and forms the second spin pair with O'Neill. Its aft wall is the far side of the counter-rotating interface. Its sky runs a 10 hour day, the shortest of the four.

A wide aerial view along the rotor: parkland and blocks below, megaframe towers and the curved city rising ahead.
Bernal from 120 m up: parkland, lakes and mid-rise blocks, with megaframe towers rising to the sky. Open this view
Unrolled ground plan of Bernal (Rotor 3): districts, parks, lakes, streets, metro and landmarks, 15.7 km around by 2.5 km along the axis. The left and right edges are the same street.
Bernal (Rotor 3): forward is up, the aft end wall at the bottom. A pin with a ring is above the 150 m level; its colour is the gravity band.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

What is drawn

  • Mid-rise residential
  • Premium residential
  • Civic and parkland
  • Lake park
  • Urban core
  • Vertical residential
  • Axis access
  • Service
  • Park
  • Lake
  • Plaza
  • Ring, spoke and boulevard streets
  • Arterial and collector streets
  • Metro
  • Axis station (ascender tower)
  • Landmark tower

Views in Bernal

  1. A terrace street in Bernal at ground level, 1.0 gA mid-rise street in Bernal (Rotor 3) at eye height: a bike lane, red-roofed terraces and a boulevard that runs on into the curve of the city. Bernal's day lasts 10 hours, the shortest on the station.On the scenes page
  2. Lakeside in Bernal at ground level, 1.0 gA lakeside path in Bernal, toward its forward end wall. A resident walks the shore, towers stand across the water and the upper city fills the sky.On the scenes page
  3. Bernal from 120 m at 120 m, 0.95 gBernal from 120 m up, looking along the rotor. Parkland, lakes and mid-rise blocks lie below, and the megaframe towers carry the eye up to the sky membrane and across the curve of the world.On the scenes page

O'Neill Rotor 4

O'Neill is the forward rotor and the last one built; it reached full spin in 2044. Beyond its forward wall lie the momentum bay and the bearing gallery, where its hub faces the industrial rotor's and the two turn against each other. Its day is 12 hours.

A field of crowned towers and spires from above, with megaframe ribs climbing toward the sky.
O'Neill from 120 m up: a field of crowned towers and spires. Same generator as the other rotors, a different seed and a different city. Open this view
Unrolled ground plan of O'Neill (Rotor 4): districts, parks, lakes, streets, metro and landmarks, 15.7 km around by 2.5 km along the axis. The left and right edges are the same street.
O'Neill (Rotor 4): forward is up, the aft end wall at the bottom. A pin with a ring is above the 150 m level; its colour is the gravity band.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

What is drawn

  • Mid-rise residential
  • Premium residential
  • Civic and parkland
  • Lake park
  • Urban core
  • Vertical residential
  • Axis access
  • Service
  • Park
  • Lake
  • Plaza
  • Ring, spoke and boulevard streets
  • Arterial and collector streets
  • Metro
  • Axis station (ascender tower)
  • Landmark tower

Views in O'Neill

  1. A core street in O'Neill at ground level, 1.0 gA street through the urban core of O'Neill (Rotor 4). Tall arched frontages stand close on both sides and the street runs into the dense center of the district.On the scenes page
  2. Lakeside plaza in O'Neill at ground level, 1.0 gA paved plaza on the shore of a lake in O'Neill. A resident stands at the water's edge, reeds line the shore and the city rises across the lake and the ground climbs away along the ring.On the scenes page
  3. Garden villas in O'Neill at 18 m, 0.99 gThe estates of O'Neill (Rotor 4) from a raised walk: detached villas on lawns the size of a city block, with hedges and planted trees. The richest districts trade density for open ground, and the megaframe carries the density overhead.On the scenes page
  4. Estates and lake from 60 m at 60 m, 0.97 gThe estate district of O'Neill from 60 m up. Villas in their gardens line a curving street, with a lake and parkland beyond.On the scenes page
  5. O'Neill from 120 m at 120 m, 0.95 gO'Neill's urban core from 120 m up: a field of crowned towers and spires with megaframe ribs climbing between them. O'Neill is the forward rotor, and it reached full spin in 2044.On the scenes page

Ehricke Industrial rotor

Ehricke is an open lattice in vacuum, not a floor, so it is drawn as three strips, one for each gravity band: 0.35 to 0.45 g in the outer band, 0.2 to 0.3 g in the middle and under 0.15 g in the inner band. Each strip is drawn at its own radius, so they narrow toward the axis. The rotor turns once every 143 seconds, the same way as Tsiolkovsky and Noordung, and most of its volume is left empty on purpose.

The industrial rotor unrolled into three gravity bands, outer band on top, each drawn at its own radius so the strips narrow toward the axis. Rim rings, spokes, girders, cargo rails and equipment pads.
Band plan: the three gravity bands side by side, drawn at their own radii. The shipyard side is at the top, the momentum bay at the bottom.

Drag to pan. Pinch, Ctrl and wheel, or the buttons zoom. Arrow keys and + and - work when the map has focus.

End-on section of the industrial rotor: rim ring, spokes, the three gravity bands with their g values, the stationary spine at the centre and the open vacuum between.
End-on section, seen from the spaceport end. Spin: clockwise.

What is drawn

  • Tank farm
  • Process unit
  • Utility plant
  • Fabrication cell
  • Container racks and rail yard
  • Staging and crew modules
  • Assembly truss and expansion bay

Views in Ehricke

  1. A cargo tug on its rail 1,620 m from the axis, 0.32 gA cargo tug carries a pod along one of the axial rails in Ehricke's outer band. Tugs move slowly and deliberately along these rails, hauling containers between the two ends of the rotor.On the scenes page
  2. A tank farm in Ehricke 1,550 m from the axis, 0.31 gA tank farm on the outer band of Ehricke, the industrial rotor, at about 0.4 g. Six horizontal vessels and two spheres sit on a lattice deck in open vacuum. The view is from the middle band, looking outward.On the scenes page
  3. Industrial rotor 85 m from the axis, 0.02 gAn open truss that is 70 to 80 percent vacuum, carrying cargo, tank farms and robotic logistics. Material from the Moon and the asteroids is stored and processed here.On the scenes page

Off the map

A few views sit too far from the drawings to pin: the satellites, the aft power field and the wide shots from cislunar space. They open in the simulation like any other.

Why these names

The rotors are named for the people who drew the idea first, in the order they drew it.

Sources and further reading

  • The station at a glance Concordia sits in the Earth-Moon L5 region, 384,400 km from Earth.
  • Places in Concordia Concordia is a few dozen kilometres of streets, farms, factories and docks.
  • Scene atlas This is a guide to eighty-four views of Concordia, grouped by where they are: streets and parks, the climb to the axis, the machine rooms, the spaceport and the outside of the...