Space mining and the non-appropriation puzzle.

At the center of the debate is one distinction: the difference between owning territory and owning what you take from it. Space law flatly forbids the first. Whether it permits the second is the unresolved question, and the prospective value of lunar and asteroid ventures rides on the answer.

The materials at issue are concrete. Water ice at the lunar poles can be split into hydrogen and oxygen for rocket propellant, which would let a mission refuel in space rather than carry everything up from Earth. Asteroids and the lunar surface also hold metals and minerals. The instruments that govern all of this were written before any of it was feasible, and they either disagree or fall silent at exactly the point where extraction becomes real. The genuine dispute is whether a right to use resources is legally the same thing as the forbidden appropriation of territory, and which forum has the authority to decide.

The Outer Space Treaty of 1967 is the constitution of space law, and it is nearly universal: 118 states are parties and 20 more are signatories as of October 2025 (UNOOSA). It entered into force on 10 October 1967. Its Article II states that 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" (UNOOSA). In plain terms, no country may plant a flag and call a patch of the Moon its territory.

Article I points the other way for activity that stops short of claiming territory. It declares that exploration and use "shall be carried out for the benefit and in the interests of all countries" and "shall be the province of all mankind," and that outer space "shall be free for exploration and use by all States" (UNOOSA). Appropriation of the body is forbidden; use of space is free.

Between those two poles sits the silence that drives the whole dispute. The treaty never says whether the ice or metal a mission removes from a celestial body may be owned once it is out of the ground. It addresses appropriation of the body, not molecules extracted from it, and there is no authoritative interpretation resolving which side of the line extraction falls on (Congressional Research Service).

A later treaty tried to answer the question directly. The Moon Agreement was adopted by UN General Assembly resolution 34/68 on 5 December 1979, opened for signature on 18 December 1979, and entered into force on 11 July 1984 (UNOOSA). Its Article 11 declares that "the moon and its natural resources are the common heritage of mankind" (Article 11(1)), states that the Moon "is not subject to national appropriation" (Article 11(2)), and bars its surface, subsurface, and natural resources "in place" from becoming the property of any state, organization, or person (Article 11(3)) (Lewik). Article 11(5) requires states parties to establish an international regime to govern exploitation of lunar resources as such activity becomes feasible, with an equitable sharing of benefits (Article 11(7)).

"Common heritage of mankind" is a term of art. It means, in short, that a resource belongs to everyone collectively and may be exploited only under a shared international regime that distributes the benefits, rather than being claimed first-come by whoever reaches it. The idea is rooted in developing-country positions associated with the Group of 77.

The Moon Agreement never attracted a major spacefaring power, and its membership is small. Saudi Arabia notified its withdrawal on 5 January 2023, effective 5 January 2024, the first withdrawal by any state from a United Nations space treaty, leaving 17 states parties (The Space Review). Because a treaty binds only its parties, the common-heritage rule is directly binding on those 17 states and not on the countries doing most of the relevant work.

Into the treaty's silence, several states legislated. The United States moved first. The Commercial Space Launch Competitiveness Act, Public Law 114-90, signed on 25 November 2015, added 51 U.S.C. 51303, which entitles a US citizen engaged in commercial recovery to "possess, own, transport, use, and sell" an asteroid or space resource obtained, "in accordance with" the international obligations of the United States (Cornell Legal Information Institute). The same law disclaims territorial ambition, though it does so as a non-operative statement: Section 403 records "the sense of Congress that" the United States "does not thereby assert sovereignty or sovereign or exclusive rights or jurisdiction over, or the ownership of, any celestial body" (GovInfo).

Three more national laws followed the same pattern of granting title to extracted resources while requiring government authorization. Luxembourg's Law of 20 July 2017 provides in its Article 1 that "space resources are capable of being appropriated," the first European framework of its kind (Luxembourg Space Agency). The United Arab Emirates issued Federal Law No. 12 of 2019 on 19 December 2019, providing for operators' ownership rights over resources they exploit under agency authorization (UAE Ministry of Justice). Japan's Space Resources Act (Act No. 83 of 2021) was published on 23 June 2021 and entered into force on 23 December 2021, making Japan the fourth country to enact such a law; a permit-holder owns the resources it mines per its approved plan (Library of Congress).

In parallel, the United States built a plurilateral political instrument. The Artemis Accords, adopted on 13 October 2020, are a non-binding set of principles that had 70 signatories as of July 2026, with Mauritius becoming the 70th on 17 July 2026 (SpaceNews). Their Section 10(2) affirms "that the extraction of space resources does not inherently constitute national appropriation under Article II of the Outer Space Treaty" (NASA). The Accords require signatories to notify the UN Secretary-General of extraction activities and to feed their experience into multilateral efforts, including the ongoing work at the UN Committee on the Peaceful Uses of Outer Space (NASA).

The permissive reading holds that Article II bans claims of territorial sovereignty over a celestial body, not the removal and use of resources from it. Read together with Article I's freedom to use outer space, extracting and owning resources is lawful, analogous to a vessel keeping fish taken from the high seas without owning the ocean. On this view, national laws recognizing title to extracted material implement the Outer Space Treaty rather than violate it, and expressly disclaim sovereignty over the body itself. This is the position reflected in the domestic statutes and in Artemis Section 10(2) (NASA; Cornell Legal Information Institute).

A second camp, comprising various states and legal scholars who favor a multilateral-first approach, counters that compatibility with the non-appropriation principle is a contested question of international law that should be settled by all states together, not through domestic statutes or a US-led instrument. On this view, national laws and Artemis Section 10 assert a self-serving interpretation that prejudges a question reserved for the proper forum, the UN Committee on the Peaceful Uses of Outer Space, and risks a de facto "first come, first served" order. Some in this camp read "by any other means" in Article II broadly enough to reach the appropriation of resources in place (Congressional Research Service).

The common-heritage tradition, associated with parties to the Moon Agreement and with developing-country positions, goes further. It holds that the Moon and its resources are the common heritage of mankind, that resources in place cannot become anyone's property, and that exploitation must await an international regime with equitable benefit-sharing that gives special consideration to developing countries. On this view, appropriating resources ahead of such a regime is inconsistent with the agreed framework, even though the Moon Agreement binds only its parties (Lewik).

A related flashpoint is deconfliction. Artemis Section 11 establishes voluntary "safety zones," areas around operations where signatories coordinate to avoid "harmful interference," and Section 11(11) commits them to "respect the principle of free access to all areas of celestial bodies" and describes such zones as ultimately temporary (NASA). Critics argue that de facto exclusion zones could function like appropriation over time; proponents cast them as a due-regard coordination tool required by the treaty's own duty to avoid harmful interference.

Two efforts are trying to fill the gap. The first is non-governmental. The Hague International Space Resources Governance Working Group, hosted at Leiden University, adopted 20 "Building Blocks for the Development of an International Framework on Space Resource Activities" by consensus on 12 November 2019 (Leiden University). The Building Blocks propose neither a pure common-heritage regime nor pure domestic free-market licensing, but an enabling international framework that would combine resource rights and priority mechanisms, an international registry, deconfliction and safety rules, environmental safeguards, and some benefit-sharing, offered as input to future intergovernmental negotiation.

The second effort is intergovernmental. In 2021 the COPUOS Legal Subcommittee established a Working Group on Legal Aspects of Space Resource Activities, with a five-year work plan agreed in 2022 (UNOOSA). It is tasked to study the existing legal framework, assess whether it should be expanded, and develop a recommended set of initial principles, aiming to report by 2027 for possible action by the General Assembly. The Working Group is chaired by Steven Freeland of Australia, with a vice-chair from Egypt (UNOOSA).

As of the 2025 sessions, that recommended set of principles remains in draft and has not been adopted. States broadly agree that the Outer Space Treaty, non-appropriation, and peaceful use remain foundational, but they continue to disagree on benefit-sharing, the role of the private sector, licensing, and how environmental obligations should be implemented (Open Lunar Foundation). The core question, whether a right to use resources is legally distinct from the forbidden appropriation of territory, and who has the authority to decide, is still open.