Can the U.S. Annex the Moon?

And other questions about what countries, and private companies, can and can’t do in space under a 1967 U.N. treaty.

A man walking his dog in space.
Photo illustration by Slate. Photos by Getty Images Plus.

On July 10, Future Tense and the JustSpace Alliance will hold an event titled “How Will We Govern Ourselves in Space?” in Washington. For more information, to RSVP, and to watch the livestream, visit the New America website.

Fifty-two years ago, the nations of the world sat down to ratify the first treaty that would govern outer space. It was the height of the Cold War, and although the space race was in full swing, it would still be two years before the Apollo moon landing. Nuclear apocalypse seemed significantly more likely than space settlement.

So it is unsurprising that the 1967 U.N. Outer Space Treaty was primarily designed to do two things: bar individual countries from claiming sovereignty over celestial bodies, and bar anyone from putting nukes in space. Article II of the treaty stated that “outer space, including the moon and other celestial bodies, is not subject to national appropriation.” It also established outer space as “the province of all mankind,” a place every nation is free to explore and use in peace. Article IV prohibited countries from placing “objects carrying nuclear weapons or any other kinds of weapons of mass destruction” in outer space.

As the Cold War wound down and the space race faded, we entered several decades of relative inactivity when it came to outer space. Now, that’s changing rapidly. Climate change has renewed interest in our becoming a multiplanetary species. Space is no longer the exclusive domain of the Russians and Americans—the United Arab Emirates, China, India, Nigeria, and other countries now have space programs. And with the rise of companies like SpaceX and Blue Origin, a private space race is on, with plans for tourism, asteroid mining, and even off-Earth settlements. The world is suddenly realizing a rather unfortunate fact: Other than policing where we put our nukes and where we plant our flags, the Outer Space Treaty doesn’t tell us much.

So what can you do in outer space? We decided to find out.

Can the U.S. annex the moon?

Nope. This one’s pretty clear and is one of the few things actually governed by the Outer Space Treaty. Nations can’t lay sovereignty claims over celestial bodies. Case closed.

Can Elon Musk settle Mars?

This one is tricky because there may be a loophole in the Outer Space Treaty. At the time the treaty was negotiated, no one was thinking about private companies or wealthy individuals launching into outer space. And so the treaty says little about what private citizens and companies can and can’t do in outer space.

Some argue that because the treaty does not explicitly forbid it, it is possible for private actors to claim territory in space. The problem for that side of the argument is an article in the treaty that makes the signing countries responsible for “national activities in outer space” regardless of whether they are carried out by government or private entities. For instance, in 2018 an American startup called Swarm Technologies launched four satellites after having been denied a license by the Federal Communications Commission. The incident raised concerns that the company may have made the U.S noncompliant with the Outer Space Treaty. The FCC slapped Swarm with a fine of nearly $1 million, but allowed the company to continue operating under a strict new compliance regime.

The U.S. would have to approve the launch of a SpaceX settlement mission and make sure the company’s activities in space didn’t violate the OST. And per the treaty, the mission’s personnel and materiel, including ships and habitats, would remain under the jurisdiction of the launching country. If the U.S. were to recognize property claims made by Martian settlers under those circumstances, it would look a lot like colonization by proxy.

So we’re going to call this one a “no.”

Can a space tourist bring back moon dust?

Yes … probably.

There are no conservation laws in outer space, so the countries licensing the tours would make the rules. Some advocate for declaring the site of the first moon landing a UNESCO heritage site, pointing out that the next country to reach the moon could erase Armstrong’s footprints without violating any laws. There’s also concern that we could erode the moon one souvenir at a time.

But governments have been allowed to take scientific samples from celestial bodies, which serves the common good by advancing humanity’s knowledge of outer space. All of the lunar materials collected by NASA were declared to be national treasures and (with the exception of samples given as goodwill gifts to foreign governments) are U.S. government property. It’s not illegal for private citizens to own lunar materials, just very difficult to acquire them legally. Almost all of the U.S. samples that have ended up in private hands were stolen, whether directly from NASA or from a foreign government that had received one as a gift.

But moon rocks from the Soviet space program have been sold legally on the private market. And private ownership of lunar material has been upheld in the U.S., though admittedly under exceptional circumstances: A bag used by Neil Armstrong and Buzz Aldrin to collect lunar samples, which still contained moon dust, was stolen, recovered, and then mistakenly sold by U.S. Marshals at a forfeiture auction. NASA sued the purchaser to recover it and lost in federal court.

Can you mine gold on Mars?

It depends on whom you ask. The U.S. government says yes.

We don’t know for sure that there are significant gold deposits on Mars, though it’s plausible given the amount of volcanic activity on the planet. We do have direct evidence of valuable resources like titanium and, more importantly, ice, which in addition to sustaining life can be used to make rocket fuel. Remember, the OST prohibits any country from appropriating celestial bodies. But the countries that support the right to mine, own, and sell materials in outer space argue that the ban on appropriation of celestial bodies doesn’t apply to resource extraction. Their opponents argue that mining is a form of appropriation and that resources in space belong to everyone. In 2015 the U.S. Congress passed the Commercial Space Launch Competitiveness Act, recognizing the rights of American companies to own resources mined in space. Luxembourg passed a similar law in 2017, raising concerns that the era of international cooperation ushered in by the 1967 space treaty might be undermined by national legislation, setting off a resource rush. Since 2015, a number of countries, including Russia, China, and India, have signaled their intent to pursue space mining.

Can you tow an asteroid to Earth?

You can’t own an asteroid, but nothing in the treaty says you can’t move one. Obviously we want to be able to redirect asteroids away from Earth so we don’t go the way of the dinosaurs. It’s hard to think of a more clear-cut example of using space for the common benefit of mankind.

What about bringing one into Earth orbit for scientific or commercial reasons? Changing the path of an asteroid has security implications. A wayward asteroid could destroy satellites or, if it was big enough to survive the fall through the atmosphere, hit the Earth itself. Ultimate responsibility would, again, lie with the nation that licensed the mission. NASA had a program to take a boulder from the surface of an asteroid, tow it to the moon, and park it in orbit for study. But the program was canceled in 2017.

Can you set up a gated community on an asteroid?

You could build a gate, but it wouldn’t do you much good. The right to explore and use space includes the right to build bases, not to exclude people from them or obstruct access to any part of a celestial body. Noninterference zones have been floated as a way of establishing safe boundaries for activities in space, but granting exclusive licenses to operate in a given location could establish a de facto property right.

Time for a new space treaty?

Sure looks like it. None of these scenarios has been tested yet, so it’s not surprising that laws made half a century ago to govern things that nobody has ever done are probably inadequate. We’re betting that all of this ambiguity will eventually lead the spacefaring nations to hash out a new treaty. But it might be best to wait until there are real activities to regulate.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.