Legitimacy of commercial exploitation of mineral resources in outer space: Does the US’ Executive Order violate international law?

In an attempt to give impetus to the United States’ ‘free market’ policy towards commercial mining of mineral resources in space, President Trump in April 2020 issued an executive order (‘Order’) for promoting “commercial participation in the long-term exploration, scientific discovery, and use of the Moon, Mars, or other celestial bodies”. This Order was issued under the Commercial Space Launch Competitiveness Act of 2015, which was its first legislative measure to implement the policy of supporting claims of private firms over resources extracted from space.

This instrument seeks to further the United States’ stance that resources in space should be available for commercial exploitation by private enterprises. It follows the mandate of Space Policy Directive-1 of 2017 which envisages the creation of a program for “exploration with commercial and international partners to enable human expansion across the solar system.” However, under the international space law regime, the legitimacy of such commercial exploitation of space resources will only continue to be a contentious issue.

In this article, the author attempts to address this question of the legitimacy of United States’ space policy, as promulgated under the Order and argues in favour of the permissibility of commercial exploitation of space resources under international law.

State v individual: The permissibility conundrum

Article II of the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (‘Outer Space Treaty’) stipulates;

“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.”

A careful perusal of the wording of Article II evinces that it unequivocally limits the scope of restriction to apply only to states, and not to other entities such as private firms. This construction of Article II of the Outer Space Treaty has been reaffirmed by scholars and international jurists. Proponents of this view often rely on the doctrine of expressio unius est exclusio alterius: that expressly including one thing implies the exclusion of the alternative. The omission to explicitly bring private entities within the ambit of this restriction forms the core of the argument that the Outer Space Treaty does not intend to forbid private endeavours from using space resources for commercial purposes.

Scholars maintain that, under the Outer Space Treaty, private individuals and commercial entities (not subjects of states) are not restricted from commercially exploiting space resources, including celestial bodies such as asteroids. It is important here to highlight that their treatises also form a part of the corpus of international law on the subject as per Article 38(1)(d) of the Statute of the International Court of Justice.

This argument is further strengthened by the preamble of the Treaty which recognizes the common interest of all mankind in “exploration and use” of outer space. This is important because a Treaty has to be interpreted in light of its preamble according to the Vienna Convention on Law of Treaties [Art.31(2)]. Hence, it is evident that the Outer Space Treaty acknowledges that space resources can be explored and used, provided that it is not done by states.

A case can, therefore, be made out that: by recognizing ‘usage and exploration’ of space resources and explicitly restricting states from the appropriation of space resources, the Outer Space Treaty implicitly permits private endeavours of individuals and commercial firms to explore and exploit space resources.

Moon Agreement and its implications for the United States    

The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies (‘Moon Agreement’) details more comprehensively the extent of permitted exploitation of space resources. It calls for space resource exploitation to be conducted under an international regime that would require “equitable sharing by all States Parties in the benefits derived from space resources” and proscribes isolated attempts, public or private, to engage in the mining of resources.

In addition, Article 11 of the Moon Agreement, recognizing the natural resources on the Moon as the common heritage of mankind, asserts that

“Neither the surface nor the subsurface of the moon, nor any part thereof or natural resources in place, shall become the property of any State, international intergovernmental or non-governmental organization, national organization or non-governmental entity or of any natural person.”

Hence, the Moon Agreement categorically prohibits the exploitation of natural resources from the Moon, in direct contravention with the space policy of the United States. This issue was raised during the 55th session of the Legal Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPOUS). Several delegations expressed the view that the United States’ measures providing for private indulgence in the extraction of natural resources were contrary to the position it took during the negotiation of the Moon Agreement. The United States, however, maintained its position that since it is neither a signatory nor has ratified the Moon Agreement, it is exempt from the obligations arising under it.

The Order follows this position and additionally clarifies that “the United States does not consider the Moon Agreement to be an effective or necessary instrument to guide nation-states regarding the promotion of commercial participation in the long-term exploration, scientific discovery, and use of the Moon, Mars, or other celestial bodies.”

Absence of a customary norm concerning exploitation of space resources

Since there is no international instrument that obligates the United States to prohibit private entities from commercially exploiting space resources, an argument can only be made to that effect by tracing a norm under customary international law. That is, for the restriction under the Moon Agreement to apply to the United States, it will have to be elevated and accepted as a customary international law norm.

Dr. Ricky J. Lee in his treatise ‘Law and Regulation of Commercial Mining of Minerals in Outer Space’ (p. 113) states that owing to the limited acceptance of the Moon Agreement, it is virtually impossible to consider its operative provisions as reflecting customary norms. Moreover, Mr. Timothy Nelson cites the unequivocal provisions of the Moon Agreement relating to mineral exploitation in outer space as a possible explanation for states’ aversion from signing it, which further challenges the customary status of this restriction.

The United States maintains a similar position and through the executive order has stated that it “shall object to any attempt by any other state or international organization to treat the Moon Agreement as reflecting or otherwise expressing customary international law.” This position resonates with the practice in Luxembourg, China, India, and middle eastern countries such as Saudi Arabia and the United Arab Emirates. Hence, in consonance with the views of international scholars and state practice to the contrary, it can be argued that there exists no customary rule prohibiting states from allowing private entities from commercially mining on planets, asteroids, and the Moon.


The executive order, for the most part, follows the existing regime of international space law. From a legal standpoint, there is no international instrument that creates binding obligations for the United States to prohibit private entities from engaging in commercial mining of space. Additionally, there is no prohibitive rule in customary international law regarding the illegality of unilateral exploitation of space resources. Therefore, relying on the Lotus Principle – that whatever is not explicitly prohibited under international law is implicitly permitted – it can safely be contended that the United States is in complete observance of its obligations under international law of space.

Notably, the rapid pace at which technology related to space mining capabilities is developing and the idea of commercial exploitation of these resources is soon to be a reality. The economic incentive for this growth is evident with NASA estimating the value of this industry to be around US$700 quintillion. Hence, in order to avoid conflict, it is imperative that the international community, through multilateral dialogues, attempt to resolve the existing legal uncertainty regarding the possibility of commercial mining of space resources by private entities. The effort should not be to prohibit, rather it should be aimed at instating a framework that ensures that the interests of all the stakeholders, including non-space faring nations, are protected.