TLA Colony is a cylinder with slightly curved walls having an average circumference of 1.312km and a length nearly equal to its diameter.
It usually rotates at around 1.2 RPM. The wall has an average tangential velocity of around 25m/s, so jumping from the central axis to the wall would be comparable to jumping out of a moving car on a highway, possibly survivable but severely injuring (Zeta mentions in AG119). Spin rate is controlled by way of balance between the habitat and service modules of the colony, which have about equal mass and spin in opposite directions to cancel out gyroscopic effects and allow the colony to maintain a stable attitude. But its attitude can be adjusted by changing the rotation rate of one half of the colony, acting like a giant reaction wheel.
The colony's superstructure is made up of an iron-nickel skeleton, built from materials extracted from an M-type asteroid, metal panels also made of iron-nickel, and glass panels made from silicates from an S-type asteroid. The structure also contains a lot of other metals, ceramics, and plastics made in space mostly from asteroid materials.
Radiation shielding in its deep space environment is accomplished with a two-part system. A water barrier less than 1 meter thick encloses the entire colony, reducing most kinds of particle radiation inside to levels comparable to Earth's surface pre-collapse. Electromagnetic radiation is deflected using an active magnetic shield encompassing the colony. The water barrier also plays an important role in thermal regulation, circulating to bring absorbed heat from the constant exposure to sunlight to the colony service module which dissipates heat through three radiator panels about as long as the entire colony.
The glass wall and the water barrier is sectioned off into segments connected by valves that can be quickly shut in the event of a wall breach. Due to the large volume of the atmosphere, a small breach would not be catastrophic and engineers would have adequate time to respond before the situation became life-threatening. But like all colonies, a number of small shielded pressure-vessels are attached to the exterior of the wall as emergency shelters.
Electricity is generated by the colony's hydrogen fusion reactor located in the service module. This reactor is very stable and safe, but in the event of catastrophe, the two halves of the colony can be quickly separated and moved apart by emergency solid rocket motors. For the colony's own propulsion and maneuvering capabilities, limited though they are, it has a number of nuclear thrusters that can be used for emergency stabilization and hazard avoidance. But the colony lacks the propulsive capacity to relocate itself to a drastically different orbit.
The entire habitable section of the colony is pressurized with a nitrogen-oxygen atmosphere constituted of oxygen extracted from Lunar rock and nitrogen refined from ammonia mined from comets and icy outer solar system moons. The plant and algae life on the colony is sufficient to create a natural oxygen-CO2 cycle for the colony's normal human and animal population. Air pressure varies by distance from the wall, but everywhere in the TLA atmosphere has a survivable air pressure (at least in the short term, at the central axis).
Centrifugal artificial gravity experienced by someone standing on the wall is on average 0.33G, about one third of Earth's surface gravity and double that of the Moon. This is sufficient gravity to prevent bone density loss and other detrimental effects of weightlessness (it is more common for colonies to have higher gravity than this, TLA’s is slower to be more accessible to Lunatics)
The service module also houses the colony’s main computer cores, extremely powerful processors shared by all technopaths on world. The powerful resource of this computer system and of TLA’s sensitive data from its students’ training record is protected from physical sabotage by the isolated position of the colony, with only authorized personnel allowed on world, and it is protected from cyberattack by the three TLA admins. By academy regulation, at least two admins must remain on world at any time.
Due to the principle of centrifuge, standing and walking on the colony wall is very much like moving in a natural gravity well, you can jump and appear to fall back down, but any object not at rest on the wall will drift opposite of the direction of spin, so jumping and landing in the same spot is more challenging. This is due to the fact that all kinetic motion is linear, but a “stationary” person on a colony wall is moving with angular motion, so objects traveling in a straight line appear to be on a curved trajectory. Pouring liquids needs to be done slight ahead (spinward) of the recipient vessel. A person can easily identify the direction of rotation by turning their head, giving colony dwellers an intuitive sense of direction.
The slight curvature of the walls is barely noticeable by a person standing on them, but it has the effect of causing all loose water to gather in the center of the cylinder, where a reservoir pond at the topological low point collects it. Water is sprayed at regular intervals on all colony soil areas where plants and fungi live, and an artificial water cycle is necessary for their survival. This interior water cycle also contains the drinking water of colony inhabitants.
The "habitable strip" of the colony is unusually shaped and runs around the circumference at an angle, creating the effect of a long rectangular world about 1.5km long and about 200m wide that does not connect into a circle.
On one end is the residential block, where student housing and the housing of colony faculty and staff and their families is built. While it might have the seeming of a village of sorts, the non-student population is too small to sustain a self-contained economy, so it functions as a small outpost requiring food and provisions from off-world.
On the far end is the academic block, housing Translunar Academy proper, made up of several buildings. The medical center is located here (a linear car running along the outside of the colony wall is able to quickly transport patients from the residential block to the medical center if needed).
The middle of the habitable strip contains the TLA garden, a complex natural ecosystem maintained by its groundskeeper and professor of cybernetics theory, Reina. The garden is the site of several large scale botanical, mycological, entomological, and zoological research projects by Professor Reina and her colleagues.
This unusual design was created for psychological reasons, using a perceived closeness to nature to keep students in a good calm headspace conducive to technopathic thinking. Students need to walk through the garden and back daily to get between the two blocks of the colony.
The colony is oriented with its ends facing Solar north and Solar south, and it receives sunlight directly through the sides of the colony. About 50% of the wall is habitable and 50% is glass allowing an abundance of natural light. People on TLA experience a full rotation of the Sun close to every 60 seconds (Lunar).
Colonists naturally adjust to the rapidly changing day-night cycle and can use the sun as an indicator of short durations of time rather than days. The daily schedule of a student or resident of TLA remains similar to the natural day length of Earth, but is artificially constructed. Even on the "night" half of the colony it never becomes completely dark, but rather a nice level of twilight, due to the reflected light from the parts of the ground "above" any particular spot. During a solar eclipse by the Moon, the colony can experience total darkness.
TLA Colony orbits the Earth-Moon system in a Lyapunov halo orbit parallel to the Lunar orbital plane and with a low enough libration period that the Earth is never visible from the colony. Being in a LaGrangian orbit, its orbital period is exactly one month.
This description is far from comprehensive, so if you have any other questions about Translunar Academy or other places that exist in the Ætherverse, feel free to contact us.