3D Life Support Rack Maintenance

This is the physical side of the preventive-maintenance tradeoff: a service drone rides a rail along a rack of four life-support modules — an O2 generator, CO2 scrubber, water recycler and air filter — each wearing continuously since it was last touched. As a module wears, its panel material drifts from a clean accent colour toward a dull, rusty grime, and a small beacon lights red once its health sinks below the danger line. On each scheduled round the drone travels down the rack and services every module in sequence, wiping the grime away and resetting the wear clock, at a fixed crew-hour cost per module per round. Stretch the interval or speed up the degradation rate and you'll see panels stay dark, and beacons stay lit, for longer before the drone catches up.