Overview
- The peer-reviewed analysis published Monday, September 14, 2026, finds that even a generous one-billion-tonne water baseline with 98% recycling would let a one-million-person lunar city run out of usable water in just over a century.
- Researchers used the International Space Station's 98% water-recycling benchmark to show that without near-perfect advances in recycling or major imports, water — not power — is the binding resource for long-term lunar population growth.
- Power generation looks solvable because crater rims get near-continuous sunlight and could support roughly 3 gigawatts via large photovoltaic towers and eventual local panel manufacture.
- Smaller settlements of about 1,000 to 10,000 people could be sustained for centuries on known polar ice, while populations in the hundreds of thousands would face much shorter timelines unless water use drops sharply or new supplies are found.
- The paper stresses practical next steps — deeper subsurface prospecting, big improvements in recycling and low-water farming, water import logistics and cooperative governance — and notes that orbital missions since 2013 mapped surface ice but cannot rule out larger hidden reserves below a few meters of regolith.