Harvard Researchers Reveal Moon's Water Supply Cannot Support Mega Cities

Harvard astrophysicist Martin Elvis and Durham University professor Jonathan McDowell have determined that the moon likely lacks the water resources needed to sustain the massive urban centers described by prominent technology executives. Their new study challenges the optimistic timelines for lunar colonization that have gained traction in recent years. The researchers analyzed the feasibility of large scale settlement based on two critical resources: energy and water.

The debate gained momentum earlier this year when SpaceX CEO Elon Musk announced a pivot from Mars to building a self growing city on the moon. He suggested this goal could be met in under ten years. Blue Origin CEO Jeff Bezos has also predicted that millions of people will live in space by 2045. Elvis and McDowell decided to test these bold claims against available data. Their paper in Frontiers in Space Technologies found that while power generation is manageable, water availability presents a significant hurdle.

The team concluded that solar and nuclear power sources are sufficient to support one million inhabitants. However, the lunar water supply is far more limited. Most of the moon's water is located in permanently shadowed polar regions. Even if there is one billion tonnes of water, a population of one million would only survive for about one hundred years. This estimate assumes a water recycling rate of 98 percent, which matches the efficiency currently achieved on the International Space Station.

Elvis noted that the total water volume is modest when viewed in context. He compared the supply to an aquarium the size of Central Park filled until the Statue of Liberty is just submerged. He described it as a small lake that cannot supply a big city for very long. In contrast, a smaller settlement of 10,000 people could remain sustainable for centuries under the same conditions. McDowell added that covering the moon with cities requires finding a way to transport water there because it is not currently sufficient.

The researchers also argued that the initial estimates may be too generous. Elvis suggested the total water figure could be 20 or 30 times too large. He estimates that only one third to one half of the available water would be recoverable. His best guess is that the usable amount is about one percent of the original figure, which would reduce the sustainability period from one hundred years to just one year.

The physical state of the water adds another layer of complexity. Gordon Osinski, a planetary geology professor at Western University, noted that satellite measurements have uncertainties. He believes the water exists but requires ground confirmation. He speculated that it might resemble Arctic permafrost, with tiny ice crystals mixed into soil that are difficult to extract. Despite these challenges, McDowell emphasized that the findings are not discouraging. He stated that the truth is never negative, and that trying to build something that will not work is the real problem.

The study provides a realistic framework for future lunar planning. It suggests that while mega cities may be difficult, smaller communities are viable. The research highlights the need for accurate water assessments and efficient resource management. As interest in space settlement grows, these findings offer a grounded perspective on the logistical challenges ahead.