Moon water supply caps sustainable settlements at 10,000 people
New research in Frontiers in Space Technologies finds that current lunar water estimates are insufficient for million-person cities, limiting long-term habitation to small towns.
By Marco Kapoor ·
A new study published in Frontiers in Space Technologies concludes that current estimates of lunar water reserves support a sustainable population of only 10,000 people, not the millions envisioned by major aerospace leaders. The analysis by Martin Elvis and Jonathan McDowell challenges recent assertions that large-scale moon cities are viable in the near future.
The research responds to specific public claims made by industry executives. In February, Elon Musk stated that SpaceX had shifted its primary focus to building a self-growing city on the moon within ten years. Jeff Bezos separately claimed that millions of people would reside in space by 2045. Elvis, a senior astrophysicist at Harvard University's Smithsonian Astrophysical Observatory, and McDowell, an honorary professor at Durham University in England, tested these timelines against available data on power and water.
The authors found that energy requirements are manageable. Solar and nuclear sources would provide enough power for a million inhabitants. Water presents a different constraint. Most lunar water is located in permanently shadowed polar regions. The study assumes a total availability of one billion tonnes, a figure consistent with current scientific estimates.
Under these assumptions, a population of one million could survive for approximately 100 years. This projection relies on recycling 98% of all water used, matching the efficiency of the International Space Station. Elvis described the total volume as comparable to an aquarium the size of Central Park filled until the Statue of Liberty is just submerged. He characterized the reserve as a small lake that cannot supply a large city for an extended period.
The findings suggest that smaller settlements are more viable. A town of 10,000 residents would remain sustainable for centuries under the same recycling conditions. However, the researchers noted that the one-billion-tonne estimate may be generous. Elvis suggested the actual recoverable amount could be 20 to 30 times lower. If only one percent of the estimated water is accessible, the 100-year lifespan for a million people drops to just one year.
Uncertainty remains regarding the physical state of the lunar water. Gordon Osinski, a planetary geology professor at Western University in London, Ontario, noted that satellite measurements contain uncertainties. He compared the potential ice to Arctic permafrost, consisting of sub-millimetre crystals mixed into soil that are difficult to extract. Osinski emphasized the need for ground confirmation of these resources.
McDowell advised that the results should not be viewed as a barrier to exploration. He stated that the truth is never negative, and that attempting projects likely to fail is the negative outcome. The study indicates that infrastructure must match the available resource scale to ensure long-term viability.
