SpaceX Moon City Plan Hits Water Reality Check
Harvard analysis suggests one million residents would exhaust known reserves within a century.
By Harper Foster ·
The conflict between ambitious commercial space goals and physical reality has sharpened. Tech leaders have pitched large, self-sustaining lunar communities, but new calculations indicate the moon's water supply cannot support such density for long periods.
Elon Musk stated in February that SpaceX aims to build a self-growing city on the moon in under 10 years. Jeff Bezos predicted millions of people would live in space by 2045. Martin Elvis, a senior astrophysicist at Harvard University's Smithsonian Astrophysical Observatory, and Jonathan McDowell, an honorary professor at Durham University's Space Research Centre, analyzed these claims. They published their findings in Frontiers in Space Technologies.
The study focused on power and water. Solar and nuclear energy sources appear sufficient for one million people. Water presents a tighter constraint. Current estimates place available lunar water at roughly one billion tonnes. If a million residents used this supply while recycling 98 per cent of their water, the reserves would last approximately 100 years.
Elvis compared the total volume to an aquarium the size of Central Park filled until the Statue of Liberty was just submerged. He described it as a small lake that cannot supply a big city for long. A settlement of 10,000 people would remain sustainable for centuries under the same assumptions. McDowell noted that covering the moon with cities requires transporting water there, as current reserves are insufficient.
The baseline estimates may be optimistic. Elvis suggested the one billion tonne figure is likely 20 or 30 times too high. He estimated that only one per cent of the original figure is reliably available, which would reduce the 100-year timeline to one year. Gordon Osinski, a professor of planetary geology at Western University, added that satellite data contains uncertainties. He believes the water exists but may resemble Arctic permafrost with sub-millimetre ice crystals mixed into soil.
The researchers view the data as a planning tool rather than a deterrent. McDowell stated that the truth is never negative. He argued that what is negative is attempting to execute a plan that is not going to work.
