Moon Water Reserves Support Only 10,000 Residents

Lunar water reserves are insufficient to sustain million-person cities, a new study reveals. The analysis indicates that the moon's available water supports a population of only 10,000 people for centuries under current assumptions. This finding challenges recent claims by major tech leaders regarding the scale of future lunar settlements.

Martin Elvis, a senior astrophysicist at Harvard University's Smithsonian Astrophysical Observatory, and Jonathan McDowell, an honorary professor at the Durham University Space Research Centre, published their findings in the journal Frontiers in Space Technologies. The research examines the viability of power and water resources on the lunar surface. While the authors determined that solar and nuclear energy could support one million people, water availability presents a stricter constraint.

The study assumes the moon contains approximately one billion tonnes of water, a figure consistent with current estimates. This water is primarily located in permanently shadowed regions at the poles. If a population of one million people recycled 98% of their water, similar to the rate achieved on the International Space Station, they would exhaust the supply in about 100 years. A settlement of 10,000 residents, however, could remain sustainable for centuries.

Elvis compared the estimated water volume to an aquarium the size of Central Park filled until the Statue of Liberty was just underwater. He described the total as a small lake that cannot supply a large city for an extended period. The authors noted that their assumptions may be generous, with Elvis suggesting the actual recoverable water could be as low as 1% of the estimated billion tonnes.

The physical form of the lunar water adds complexity to extraction efforts. Gordon Osinski, a professor of planetary geology at Western University in London, Ontario, noted that satellite measurements carry uncertainties. He suggested the water may resemble Arctic permafrost, consisting of sub-millimetre ice crystals mixed into soil. This composition would make extraction difficult and requires on-the-ground confirmation.

The findings follow public statements by industry leaders. Elon Musk wrote in February that SpaceX had shifted focus to building a self-growing city on the moon within 10 years. Jeff Bezos has claimed that millions of people will live in space by 2045. McDowell stated that the results should not discourage development, noting that the truth is never negative and that attempting projects without viable resources is the real issue.