Not depicted is the Earth Departure Stage, the propellant tank shown is the hydrazine/tetroxide 'Replaceable Stationkeeping Unit', based on the Apollo service module propulsion system (The same the space shuttle\'s OMS is based on, but it used a different propellant. This uses the same prop as the shuttle) 1.3 km/s delta-v in total, more than enough for stationkeeping over a long period. These components will all fit in 3 Falcon Heavy launches and 1 Falcon 9 launch. 2 Falcon 9 launches if you want to send a Dragon capsule with the ship on its way to the moon. Replacement of RSU would consist of two launches, one for an EDS, and one for the stage itself. The stages delivered to the moon later have their own navigation systems, allowing them to be docked to the station without an EVA being performed. The initial one has a very basic system, only enough to deorbit itself after being jettisoned. This might seem like a lot of effort to replace the module, but it won\'t be needed very often as the amount of delta-v needed for stationkeeping is minimal, provided you are in a good orbit. As such, much of the initial propellant sent would be used to put the station into as stable of an orbit as possible without making it too difficult for visiting spacecraft to rendezvous with it. Centrifuge is 17m across, and spins at 6 rpm to generate 0.7g. Can easily be tweaked to move slower, but 0.7 seems like it would be the upper limit for comfort at the given size). The centrifuge is also only a sleep area, and since you\'re laying down in the pods at either end, the Coriolis force is minimized on your body. Should pods contain windows? Would this help or hurt motion sickness? Further capsules are delivered to the station via Falcon Heavy launches, for crew replacement. Future developments include additions such as multiple docking ports, allowing the station to be used as a 'rest stop' for lunar landing missions. Current job: calculate the EDS and figure out if a Dragon capsule launched at the moon full of cargo and crew could have the ability to put itself in orbit and rendezvous with the station, or if it needs a new propulsion system (if so, a scaled down RSU could work nicely) Minor todo: Decide exactly how the station is assembled: LIDS docking system, APAS system or Common Berthing Mechanism, or something in-house Future: add comms equipment, work out interior of BA-330