It may seem like science fiction, but we’re getting ready to colonize celestial bodies like the moon and Mars.

NASA and ESA’s Artemis program  aims to build a base camp on the moon by the end of the 2020s, and further research centers in the 2030s. The Chinese National Space Administration and Russian Federal Space Agency, Roscosmos, have also announced plans to build their own moon bases in the 2030s.

No one can own the moon

The prospect of space colonization poses some big questions. One of the most fundamental is whether nations or companies can actually own the moon or other celestial bodies.

According to Alexander Soucek, head of public international law at ESA, they can’t.

"A nation can plant a flag on the moon, but it doesn’t have any legal meaning or consequence. This is entrained in the Outer Space Treaty, where it’s written that no country can claim sovereignty on the moon or make it its own territory," said Soucek.

Crucially, Soucek explained, this law extends to private companies like Elon Musk’s SpaceX.

"We’re speaking about international law here. States have the obligation to transpose the law on their citizens and private companies in their territories," he said.

But can people own bits of the moon?

So far, so good — but what happens if people extract materials from the moon? Can they own and sell them? According to Soucek, this is a major point of tension.

"Country X or Y might say they have no interest in claiming the moon as national territory, but they are interested in owning materials extracted from the moon or Mars and selling them back on Earth," Soucek said.

Tensions come down to different legal interpretations of Article 2 of the 1967 Outer Space Treaty, which states: ‘Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.’

While this clearly refers to owning the moon as a celestial body, Soucek said, different lawyers have different interpretations of whether the article allows nations or companies to own parts of the moon for commercial use. 

If it is indeed possible to own parts of the moon to capitalize upon, do profits need to be shared? Is it first come, first serve? No current treaty deals with these issues.

But according to Kai-Uwe Schrogl, president of the International Institute of Space Law, the Outer Space Treaty clearly states that no one can own materials taken from the moon either.

"There are no loopholes. There are just wilfully wrong interpretations of the Outer Space Treaty. The nations that are responsible for private actors just have to say: No, you cannot own these resources. If they do, they breach international law," he told DW.

Nations agree that owning space territories not a good idea

Humanity has come a long way since European nations carved up Africa at the Berlin Conference of 1884-1885. The future of lunar colonization looks to be less blood thirsty, with universal agreement that owning territories on the moon is a bad idea.

"Everyone wants to explore outer space, so there is an international understanding of the greater good of international cooperation," Soucek said.

Observers often view space exploration as a beacon of hope for global peace, with treaties solidifying cooperation into binding agreements. And for the most part, countries appear to strive for this cohesion in space.

After all, the Outer Space Treaty was successfully established during the Cold War, amid great international tension. Now too, Russian astronauts are working side-by-side with astronauts from the West on the International Space Station, despite tensions over the war in Ukraine. 

How long can cooperation in space last?

While Schrogl agrees that the major international space powers have learned from colonialism, he is less optimistic about the longevity of international cooperation in space.

Although the treaties have helped establish a baseline international consensus, some disagreement over space exploration appears inevitable. Early this year,  NASA chief Bill Nelson said in an interview that China could someday land on the moon and declare the satellite as its own territory.

China vehemently rejected the claims, re-emphasizing its commitment to peace and demilitarization in space. 

"All space powers will lose when there is anarchy in space and on celestial bodies," said Schrogl. "[The idea of anarchy in space] was exactly what led to the Outer Space Treaty, when the space powers were not sure how each of them would develop. We should not make the mistake of changing this path now in this situation."

Edited by: Clare Roth