Colonia

Needed systems

Life support

Air quality: O2, CO2, climate control, circulation, filtering

Gravity

Food production/agriculture

Water supply

Sewage handling

Recreation

Heat removal (air conditioning)

Heat exchanger disks at each end that double as radiation shielding?

Power generation

Backup/emergency power generation

Power grid/distribution

Lighting - natural (fiber-optic?)

Lighting - agricultural (fiber-optic?)

Light collection area (external mirrors, etc) must be about the same as lighted surface area inside, divided by some factor since there's no atmosphere, to achieve earth-like results. Especially important for the plants to grow quickly.

Lighting - artificial

Wobble control/balance

Shift cooling water in heat exchangers to different radii? Put one exchanger disk at each end for full control

Docking

Radiation shielding

Contain regolith/soil in layers for agriculture. Put radiation-hardened breeds in outer rings and most delicate plants in inner rings

Communications

PC networking

Computer controlled systems/mainframe

Administration/flight planning

Industrial options/exports

Mining options

Self-repair (manufacturing)

Maintenance

Transit between levels

Emergency broadcasts

Fire suppression

Leak containment

Radiation storm shelter

Design revision/improvement questions to ask

Simplicity

Few moving parts

Redundancy

Interchangeability

Low mass

Avoid catastrophic failure modes

Increase citizens enjoyment

Maximize parts that can be replaced on-station

Upgradeability/growth potential

Fail safe/passive systems