New Study: Water Shortage May Hinder City Construction on the Moon

- If you, like Elon Musk, dream of a future where large numbers of humans can live on the moon, you will likely feel disappointed. Despite the possibility of trillions of pounds of water trapped inside tiny glass beads scattered across the moon's surface, scientists estimate that this amount will not be sufficient to sustain life in a large city for a long time, according to a study published in the journal Frontiers in Space Technologies on Monday.

Musk announced in February that his space company SpaceX shifted its focus from developing a settlement on Mars to "building a self-sustaining city on the moon," because achieving that would be faster and could happen "in less than 10 years," according to him. This raised another question: "What size city could be supported by this amount of water on the moon?

The answer was very surprising," said Martin Elvis, the lead author of the study and an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, to Afaq News. By estimating a billion tons of water as a "generous" estimate, Elvis and his colleague astrophysicist Jonathan McDowell found that a million people, roughly the population of Stockholm, would consume this amount entirely in less than two and a half years if used for drinking, hygiene, food cultivation, rocket fuel, and breathing, according to the study.

However, efficiently recycling water could significantly extend this duration. With a recovery rate of 98%, as in the International Space Station, the water could suffice for a city of one million people for about 100 years.

However, this requires very strict conservation in its use, which Elvis believes is likely unsustainable. The researchers concluded that a century's worth of water supply does not seem sufficient to establish a sustainable and long-term settlement beyond Earth, despite the massive investments required to achieve that.

The researchers believe that a small city with about 100,000 people could last for 1,000 years, a duration that "seems long enough to describe it as sustainable," according to the study. McDowell told Afaaq News: "However, if the town has only 10,000 residents, it would have enough water for about 10,000 years, and then it starts to make sense, as we would have enough time to find another solution."

For example, there is "a large amount of water in the solar system," including in the asteroid belt and on Saturn's moons, McDowell explained. He added: "Therefore, future lunar inhabitants may be able to import water in the quantities needed to support large populations.

It is difficult to imagine how this could be implemented using current technology, but it may become possible in the long term." In the short term, McDowell believes that building a town on the moon could take about 30 years, not 10 years, as Elon Musk suggested. "A village on the moon" said astronomer Ian Crawford, a professor of planetary science and astrobiology at Birkbeck, University of London, who is not involved in the study, to Afaaq News: "This is an important study, and I think the researchers have provided a valuable service by adding a degree of realism to the discussion about long-term plans for establishing large human settlements on the moon."

He added that creating such settlements would require importing water or the hydrogen needed to make it from the oxygen present in lunar rocks. In the study, the researchers noted that a village of about 1,000 people on the moon, a number close to those who stay in Antarctica during the winter, could potentially use lunar water "without significant constraints."

Crawford stated that the amount of water present at the lunar poles may be sufficient in the short term to support small research sites of this size, adding that he believes "this will be the most likely use in the coming decades." However, he emphasized the importance of studying the water ice at the lunar poles appropriately before fully extracting it and using it as a water source, given its scientific significance.

Ice has accumulated on the surface of the Moon since its formation billions of years ago, therefore it "preserves a chemical and physical record of the environment in which the Earth existed throughout this period, which led to the emergence of life on our planet," according to Simon Barber, the lead researcher at the Open University in the UK who studies water on the Moon, in an interview with Afaaq News. Barber, who is not involved in the study, added: "We should, at the very least, uncover the secrets that this ice holds regarding our evolution and the evolution of our planet and other planets, before thinking about extracting it for industrial use." "A rush for resources"?

Agriculture consumes the largest share of water, as feeding one person daily may require between 2000 and 5000 liters, according to estimates from the World Bank that the study relied on. Adopting a completely plant-based diet may help reduce consumption, as producing beef requires six times the water needed to produce soybeans, while chicken requires double the amount, according to the study.

But even with consumption rationalization, the actual amount of water present on the Moon and the ease of extracting it remain unclear, according to McDowell. He explained that water may be abundant in extremely cold and shaded craters, making extraction relatively easy, but it may also exist in small quantities among rocks in vast areas of the South Pole, which could make extraction extremely difficult even if its total quantity reaches significant levels.

Barber stated that "the extreme cold and prolonged darkness" make these areas "a harsh environment for robots or humans." He added that the water is not in the form of pure ice cubes that can be melted and consumed, but is likely mixed with toxic chemicals that must be removed first.

Researchers estimate that the eight largest craters on the Moon contain about 34 million tons of water. With a limited number of large craters that can be explored, interested parties may seek to "acquire the largest and best ones and exploit the water within them," according to Elvis, who called on countries participating in the Moon exploration race to cooperate instead of competing with each other.

Crawford stated that researchers are "certainly right that the careful management of the limited lunar water reserves will be essential," adding that this requires "an internationally agreed regulatory framework" to avoid a rush for resources and the premature depletion of a valuable lunar resource.