Are there any laws governing the legality of construction on Luna? If there are, who's responsible for enforcing them?

At least vaguely related: moon structure ownership

  • $\begingroup$ From a legal point of view, what is the difference between a construction on Luna and a construction in Outer Space (cf. The International Space Station)? $\endgroup$
    – Ng Ph
    Jul 26, 2021 at 13:24
  • $\begingroup$ @NgPh: planetary protection, for one. The ISS can't harmfully contaminate anything, biological contamination from a moon base could obscure signs of lunar life. The moon being an almost certainly lifeless rock, COSPAR only requires some basic documentation (en.wikipedia.org/wiki/…). $\endgroup$ Jul 26, 2021 at 14:53
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    $\begingroup$ I didn't dive into COSPAR and planetary protections issues in my answer, but to respond to these comments briefly: Yes, PP issues are one legal difference between outposts in orbit and on the Moon. There are a few other differences, set out in the Outer Space Treaty, where certain provisions apply only to the Moon and/or celestial objects in general: eg prohibition on weapons, and a right of inspection. Oh, and COSPAR guidelines are not law, but yes, they are used as a guide for nations to implement OST obligations re pp. COSPAR provides sufficient rules, if not necessary, is how I see them. $\endgroup$ Jul 26, 2021 at 18:18
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    $\begingroup$ The emerging consensus internationally is that space resource utilization is lawful, so long as you comply with relevant international law. No difference between whether it's commercial or civil. The United States and other signatories to the Artemis Accords agree on this, and it appears to be the position of China as well at this point. Holdouts include Germany, possibly Russia, Belgium. Maybe Mexico. $\endgroup$ Jul 27, 2021 at 20:44

1 Answer 1


Ok, so I understand the question as being about a private, commercial base on the Moon. The short answer is sure: it's legal, so long as you get authorization from your "launching state".

As another answer says, the 1967 Outer Space Treaty is the primary international law instrument governing activities in outer space. Article II of the OST forbids "national appropriation" of outer space or celestial bodies, including the Moon, and Article IV forbids the creation of military bases on the Moon. Those two articles provide the most relevant limits on what you can do. The question isn't about military bases, so we can ignore Article IV. The prohibition on national appropriation is somewhat debated in the international community - a minority view is that it forbids extractive activities without additional authorization - but that isn't the question here anyway, so the relevant limitation from Article II is that you can't claim the territory under your base as your land. So you can't say "because we built this base, SpaceX owns this crater" or "now this is part of America." You can't do that.

But you certainly can build, operate, own, and control a lunar base. Article I of the Outer Space Treaty provides that outer space, including the Moon, is free for exploration AND USE by all states. Heck, Article IV explicitly says "The use of any equipment or facility necessary for peaceful exploration of the moon and other celestial bodies shall also not be prohibited." Article XII goes on to say that any installations on the Moon or other celestial bodies shall be open to inspection by Parties to the Agreement. So the OST explicitly contemplates and provides for bases on the Moon. That right there answers the question.

Oh, and although you can't own the land under your base, you can (and will) continue to own and control your base, equipment, etc. Article VIII says that ownership is not affected by being in space, and that national governments retain jurisdiction and control over their stuff, installations, people, etc. So a SpaceX base would be owned by SpaceX and governed by the laws of the United States.

In case you are thinking "ah but the OST is only about government activities, not private or commercial" NOPE. The OST was a fascinating compromise between Soviet and Western-aligned blocks in the middle of the Cold War. The core of this compromise was that commercial activities are allowed in space (what the western countries wanted) but those activities are ultimately the responsibility of national governments (the Soviets wanted space only to be for government actors). So Article VI of the OST requires national governments to "authorize and have continuing supervision" over non-government actors such as commercial companies, and for ensuring that non-government actors act consistently with the terms of the OST.

So the international law answer is that not only are lunar bases not prohibited, they are explicitly provided for. So long as a national government authorizes and supervises a commercial base, and so long as that base does not do anything that is inconsistent with international law (claim territory, host nuclear weapons, etc.) then international law is fine with it.

A commercial company building and operating a lunar base would need to get authorization by their home government; those authorizations differ by country. In modern systems, there's often a single space authority that would handle it all. In the United States, authorizations are split between NOAA, the FAA, and the FCC. It's a whole annoying thing, but not relevant to the question here. Bottom line is that yeah you need those authorizations if you are an American company.

But sure, go make a lunar base.

Edit to provide details on "who is responsible for enforcing" laws: as I hinted at above, the OST requires "launching states" to have continuing supervision over space activities of even private actors, and to ensure that those actions are consistent with the treaty. So national governments are responsible for enforcing the rules in space. If some other government thought that an American company were doing something unlawful, they would work through diplomatic channels to raise that issue with the U.S. Government. There are no space police (certainly not any ones with international enforcement powers, sorry Space Force), but the reality is that so far, in space at least, countries almost all have an interest in complying with the rules because they create predictability and safety in a very expensive and dangerous environment. To date, we have seen very very few examples of private actors running around doing unlawful things in space without getting smacked down and controlled by a national government. Enforcement has not been a problem so far, but anyway, now we're getting into another issue for another day.

  • $\begingroup$ "A commercial company building and operating a lunar base would need to get authorization by their home government;". Is the wording of Article VI clear enough that the company must get the authorization from their "HOME" government (only)? $\endgroup$
    – Ng Ph
    Jul 26, 2021 at 18:23
  • $\begingroup$ So I was using shorthand: the real language is "launching state." Where there are multiple launching states (which is likely to be the case in reality) those states should consult to determine whether one of them is most "appropriate" to exercise jurisdiction and control, or whether they should share j&c, a la how we handle the ISS. $\endgroup$ Jul 27, 2021 at 20:45

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