Harvard Researchers Question Moon City Feasibility

Dreams of massive lunar metropolises have moved from science fiction into serious business planning in recent years. However, a new analysis published this week suggests that the moon's natural resources cannot support such large populations for extended periods.

The motivation for the study came from bold public statements by major space industry leaders. Elon Musk, chief executive of SpaceX, stated in February that his company is now focused on building a self-growing city on the moon. He projected this could happen in under ten years, a timeline he viewed as faster than settling Mars. Jeff Bezos, head of Blue Origin, has also predicted that millions of people will live in space by 2045.

Martin Elvis, a senior astrophysicist at the Smithsonian Astrophysical Observatory, teamed up with Jonathan McDowell, an honorary professor at the Durham University Space Research Centre, to evaluate these claims. Their paper in Frontiers in Space Technologies focuses on two critical needs: power and water. The team determined that energy generation is a solvable problem. Solar and nuclear sources should be sufficient to power a population of one million people on the lunar surface.

Water presents a much steeper challenge. Most lunar water is thought to exist in permanently shadowed polar regions where sunlight never reaches. Current estimates suggest there is roughly one billion tonnes of water available. The researchers calculated that a population of one million could survive on this supply for only about 100 years. This projection assumes a 98 percent recycling rate, similar to the efficiency seen on the International Space Station.

Elvis described the total volume of water as modest. He compared it to an aquarium the size of Central Park filled just enough to submerge the Statue of Liberty. He noted that such a small lake cannot supply a big city for very long. A smaller town of 10,000 people would be sustainable for centuries under the same conditions. McDowell argued that covering the moon with cities requires finding a way to bring water there, as it is not currently available in sufficient quantities for that scale.

The researchers' assumptions may even be generous. Elvis estimated that the one billion tonne figure is likely 20 or 30 times too big. He believes only a third to a half of the existing water would be recoverable. His best guess is that the usable amount is about one percent of the original figure, which would reduce the 100 year lifespan to just one year.

Gordon Osinski, a planetary geology professor at Western University, added that satellite measurements contain uncertainties. He believes the water exists but needs ground confirmation. He suggested it might resemble Arctic permafrost, with tiny ice crystals mixed into soil that are difficult to extract. McDowell emphasized that the findings are not negative. He stated that the truth is never negative, and only actions based on flawed assumptions are. The study highlights that while small bases are viable, grand visions of lunar cities face significant resource hurdles.