Water, oxygen, and waste demand closed-loop life support

Minimum drinking requirements alone approach 60 million liters per year. Total water demand could exceed seven times that figure once washing, cleaning, food-shuttle decontamination, coolant losses, leakage, and transport losses are included. The population also requires roughly 8.5 billion liters of oxygen per year, while life-support systems must remove carbon dioxide and process large waste streams. Urine recycling helps but cannot make the system perfectly closed, so the fleet would need the equipment and trained labor to recover water and other inputs from asteroids. Agriculture adds a separate material problem: recycled waste can help as fertiliser, but the fleet still needs soil as well as water.