Lunar Megacity Faces Water Constraint Within a Century

Solar power on the Moon could support a million residents, but water is the bottleneck: with optimistic water supplies and high recycling, a 1-million-person Moon city might last a bit over 100 years; given current estimates of far less lunar water, that timescale collapses to only a few years for a large city, while smaller settlements could endure for centuries. Solutions include improved recycling, reduced water use (e.g., vertical farming), importing water, or locating more water beneath the surface.