Over 40 years after the Apollo missions, NASA's Artemis program plans a human return to the Moon by 2024. This milestone will test the viability of lunar bases and colonies, prompting scientists to assess the Moon's capacity to support human life.
One simplistic approach compares surface areas: the Moon spans about 15.9% of Earth's total surface (excluding oceans). At densities matching Earth's densest cities, it could theoretically house billions.
Yet fitting billions differs vastly from sustainably supporting them. Here, the Moon falls short compared to Earth.
“It’s a pretty sterile place. Each species seeks to expand its ecological niche. But the new 'niche', which is the Moon, is very inhospitable to humans,” says Darby Dyar, researcher at the Planetary Science Institute in Arizona and professor of astronomy at Mount Holyoke College in Massachusetts.
Unlike Earth, the Moon lacks precipitation, breathable atmosphere, and ecosystems for agriculture.
It faces solar storms—intense solar flares whose radiation the Moon can't deflect without a magnetic field—plus extreme temperatures and prolonged day-night cycles.
These factors seem daunting, but essentials like air, water, food, and shelter are more attainable than expected.
For an initial population of hundreds, transporting air to sealed habitats is feasible. Markus Landgraf, lunar project manager at the European Space Agency, notes: “People don’t consume a lot of air, and for a long time we won’t need to generate air on the Moon. We can bring it. Transport costs for this are still manageable.”
For tens of thousands, on-site oxygen synthesis becomes necessary, though costly. Landgraf highlights that rising space activity—needing oxygen for rockets—could drive down costs: “it makes more economic sense to build oxygen generators on the Moon for rocket propulsion, rather [than] only for drinking water and air for the settlers.”
This shared infrastructure would make air production cheaper for colonists.
Once thought bone-dry, the Moon holds significant water. “We believe there is water left since the formation of the Moon. And we know that comets, which are essentially balls of ice, periodically impact the surface of the Moon. There is good evidence to suggest that these craters where comets slammed into the surface still contain reservoirs of ice,” explains Dyar. Recent missions confirm this.
Solar winds also contribute: protons collide with lunar electrons, forming hydrogen. Combined, these could sustain a sizable population. International Space Station tech already recycles urine, sweat, and shower water into drinking supply, enabling closed-loop systems on the Moon.
Still, recycling incurs losses, requiring periodic replenishment. Extracting water from regolith or polar ice demands massive energy. “My feeling is that the colonization of the Moon will depend on our supply of hydrogen,” Dyar adds. Transport costs ~180,000 euros per kilogram.
Without precise lunar water estimates, population limits remain unclear. But Landgraf predicts the first 20 pioneers won't need local extraction for 5-10 years; imported and recycled water suffices affordably.
Lunar farming in sealed domes—mimicking Earth ecosystems with solar lighting and recycled water—could feed thousands. Extensive research confirms space agriculture viability.
