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The Moon Agreement: Hanging by a Thread?

Before 5 January 2023, no state had ever withdrawn from any of the five United Nations treaties on space-related activities. But that day, Saudi Arabia notified the United Nations Secretary-General that it was withdrawing from the fifth of those treaties - the Moon Agreement.
Image by Elen11/Getty Images.

Before 5 January 2023, no state had ever withdrawn from any of the five United Nations treaties on space-related activities. But that day, Saudi Arabia notified the United Nations Secretary-General that it was withdrawing from the fifth of those treaties - the Moon Agreement. The Moon Agreement has long struggled for practical relevance. It has gained just 18 adherents since it opened for signature on 18 December 1979. By contrast, a new, non-binding framework for lunar exploration and use - the Artemis Accords - has gained 24 signatories in less than three years. Intriguingly, Saudi Arabia’s withdrawal from the Moon Agreement comes less than six months after they signed the Accords. But in any event, a treaty with just 18 parties cannot afford to lose one. Nor can it afford to lose a party with an ambitious space program such as Saudi Arabia. What does this all mean for the future of the Moon Agreement?

The Moon Agreement

To explore this question, we need some historical perspective. The Moon Agreement came at the tail-end of a fruitful era - a now-mythical ‘Golden Age’ for developing binding international agreements relating to space. The period from 1967 to 1979 saw the conclusion of the Outer Space Treaty, the Rescue Agreement, the Liability Convention, the Registration Convention, and the Moon Agreement.

The motivation for concluding the Moon Agreement is stated in its Preamble. The Moon, as Earth's natural satellite, will play an important role in space exploration. As such, the Moon Agreement aims to promote cooperation among States in the exploration and use of the Moon in order to prevent it from becoming an area of international conflict. The Moon Agreement also recognizes the benefits that exploitation of the Moon’s natural resources could bring.[i]

As such, and similar to the other space treaties, the Moon Agreement further elaborates certain provisions of the Outer Space Treaty. However, unlike the other United Nations treaties, the Moon Agreement has only received a limited number of ratifications. And importantly, it was rejected by the then-leading space powers, the United States and the Soviet Union.[ii]

The rejection of the Moon Agreement by the then-leading space powers must be considered in light of recently declassified documents from the United States’ National Reconnaissance Office (“NRO”).[iii] These documents suggest that the Moon Agreement was nothing more than a Soviet-led (and American-supported) means of occupying time on the United Nations Committee on the Peaceful Uses of Outer Space (“COPUOS”).

On the initiative of Argentina, Poland, and France, COPUOS had been discussing a treaty to govern the Moon since 1969. In May 1971, the Soviet Union took charge of this initiative and circulated a draft treaty. Then, an NRO memorandum dated 1 September 1971 outlines a bilateral US-Soviet meeting discussing priorities of future COPUOS activities. The memorandum explains that “[t]he Soviets were soliciting US support on their proposed Moon [Agreement].” The memorandum concludes that:

“[s]ince this treaty is redundant in many regards to the 1967 [Outer Space] Treaty, the consensus is that it was proposed largely as a time consumer. The US will support the Soviet proposal.”

This suggests a desire to delay COPUOS actions that may impede US or Soviet space activities. As such, the strategy the then-leading space powers adopted was to occupy COPUOS’ time with the Moon Agreement. This behaviour by the United States and Soviet Union arguably conflicts with the good faith principle, which is stated in the Vienna Convention on the Law of Treaties (“VCLT”) to be “universally recognized”.[iv] Negotiating a multilateral treaty solely to occupy committee time, with no intention of actually signing that treaty, strikes us as potentially lacking bona fides.[v]

In any event, the US has since issued an Executive Order lamenting that the legal uncertainty regarding space resources, generated partly by the Moon Agreement, has “discouraged some commercial entities from participating in this enterprise.” As such, the US found it necessary to expressly repudiate the Moon Agreement in that Executive Order. This suggests that US complicity in the Soviet ‘time consumer’ strategy may have had adverse long-term effects.

Turning to the text itself, there are a few interesting aspects to the Moon Agreement.

First, the Moon Agreement applies beyond the Moon, to celestial bodies within the solar system (other than Earth) unless there are other specific rules relating to those celestial bodies in force.[vi]

Second, the Agreement reiterates the non-appropriation principle set out in Article II of the Outer Space Treaty and declares that “the [M]oon is not subject to national appropriation by any claim of sovereignty, by means of use or occupation, or by any other means”.[vii] It does, however, allow for the collection and removal of samples of the Moon’s minerals and other substances and protects the rights of States to freely conduct scientific investigation and exploration of the Moon.[viii]

Third, Article 11(5) of the Moon Agreement states that “State Parties undertake to establish an international régime (…) to govern exploitation of the natural resources of the [M]oon as such exploitation is about to become feasible.” Clearly, this was a touch ambitious - plans for lunar resource exploitation abound, but actual exploitation has not yet taken place.

One of the purposes of this dedicated “international régime” is to ensure resources are shared equitably. It is noteworthy in this regard that the Moon Agreement speaks of “equitable sharing” rather than “equal sharing”: to this end, special consideration is to be given to those countries that have contributed directly, or indirectly, to the exploration of the Moon.

Further, this dedicated regime should also serve to orderly and safely develop natural resources, rationally manage those resources and expand opportunities in the use of those resources.[ix]

However, the most contentious and hotly debated principle, a principle seen by Fabio Tronchetti, rightly or not, as “a stumbling block for the acceptance of the [Moon] Agreement”[x] is Article 11’s “common heritage of mankind” principle, which we will refer to as the ‘CH principle’.

The CH principle has been seen by literature as an evolution of the res communis omnium concept.[xi] However, unlike this concept, the CH principle does not confer the right to freely use and exploit a common area. Rather, it limits use and exploitation by mandating that any exploitation must be conducted according to rules established by the international community as a whole.[xii]

In other words, res communis omnium is - literally - a ‘thing of the entire community.’ As such, it remains outside the legal title of any State (or any other entity or person). It is on this understanding of the CH principle that the Accords are often seen to conflict with the Moon Agreement. We outline some of the reasons for this perception in the following section. We would be remiss, however, if we did not point out that the CH principle contained in the Moon Agreement must be seen solely in its context. Thus, the Moon Agreement itself gives meaning to the CH principle contained in Article 11. What exactly that meaning will be remains to be seen as such a dedicated regime has not yet been created.

Nevertheless, Saudi Arabia’s withdrawal from the Moon Agreement surfaces this problematique and thereby reinforces perceived conflicts between the Moon Agreement and the Accords. As such, it appears that Realpolitik may have caught up with the Moon Agreement’s lofty ideals.

The Artemis Accords

Saudi Arabia has not stated its reasons for withdrawing from the Moon Agreement, nor is it required to do so. There are various plausible reasons for withdrawal. Have the Saudis come to see the Moon Agreement as an impediment to their space program? Perhaps the United States’ requested that Saudi Arabia withdraw? Or maybe they think that the Moon Agreement has failed, and as such they wish to clean up their treaty books?

Regardless of the precise explanation, it is difficult to avoid the fact that the Saudi withdrawal comes shortly after their signature of the Accords - and that there are stark differences between the Accords and the Moon Agreement.

These stark differences are most apparent when it comes to the issue of space resource extraction and utilization. Section 10(3) of the Accords provides that:

“The Signatories commit to informing the Secretary-General of the United Nations as well as the public and the international scientific community of their space resource extraction activities in accordance with the Outer Space Treaty.”

Section 10(4) then provides that:

“The Signatories intend to use their experience under the Accords to contribute to multilateral efforts to further develop international practices and rules applicable to the extraction and utilization of space resources, including through ongoing efforts at the COPUOS.”

These provisions appear innocuous, but they confirm that the Signatories intend to extract space resources before any further international practices or rules develop regarding such extraction. This appears to differ from the process envisioned in Article 11(5) of the Moon Agreement, which can be read as requiring that the “international régime” be established before space resource extraction takes place.

Despite such differences, it is important to keep in mind that the Accords are not a treaty. Rather, they are a non-binding, political commitment that operationalizes the bedrock of international space law, the Outer Space Treaty. As such, comparing and contrasting the Accords with the Moon Agreement is not a strict like-for-like comparison.

Given this, the clearest evidence of differences between the Accords and the Moon Agreement may not lie in direct comparison of the two instruments’ various provisions. Rather, it may be the pointed silence of the former vis-à-vis the latter. The Accords’ preamble affirms the importance of complying with the Outer Space Treaty, the Rescue Agreement, the Liability Convention, and the Registration Convention. As such, the Accords specifically name and affirm all the United Nations space treaties other than the Moon Agreement.

This symbolic omission has particular weight because the Accords’ 24 signatories include three parties to the Moon Agreement: Australia, Saudi Arabia, and Mexico. Australia, in particular, was one of the Accords’ founding signatories. Clearly, during the drafting and negotiation of the Accords, Australia did not insist upon inserting a reference to the Moon Agreement. Rather, Australia later stated to COPUOS that they consider the Accords to be in harmony with the Moon Agreement. Mexico appears to take the same position.

Did Saudi Arabia not find that same harmony? Does Saudi Arabia’s withdrawal confirm the incompatibility of the Accords with the Moon Agreement? Or is it further proof that States increasingly prefer non-binding measures rather than subject themselves to binding legal instruments, such as treaties?

States that have signed but not ratified the Moon Agreement also find themselves in an interesting position. This group includes India, France, Guatemala, and Romania - all of whom signed on in the early 1980s. The effluxion of time since signature indicates that ratification is unlikely. Yet they have yet to formally announce that ratification will not take place.
Of this group of signatories, France has also signed the Accords. And we hear rumours that India will also sign the Accords. This raises an interesting legal question. While signing a treaty expresses the intention to comply with that treaty, this expression of intent is itself not binding. But signing states are required - per Article 18 of the VCLT - to:

“refrain from acts which would defeat the object and purpose of a treaty when:
(a) it has signed the treaty or has exchanged instruments constituting the treaty subject to ratification, acceptance or approval, until it shall have made its intention clear not to become a party to the treaty (…)”.

Given the differences between the Accords and the Moon Agreement, it could be argued that signing the Accords defeats the Moon Agreement’s object and purpose. This issue has likely been debated within the French foreign ministry. But given that France has not formally announced that they will not proceed to ratification of the Moon Agreement, perhaps the lawyers of the Quai d’Orsay found the same harmony that Australia presented to COPUOS? Or maybe they think that, having spent more than four decades without ratification, France’s “intention … not to become a party” to the Moon Agreement is clear? If not, perhaps signing the Accords has itself clarified France’s intention to not become a party? And if India does sign the Accords, how will the lawyers of the Indian Foreign Service view this whole situation?

If we consider further VLCT provisions, further questions arise. Over time, and with more signatories, could the Accords constitute “subsequent practice in the application” of the Moon Agreement (or the other United Nations space treaties) thereby “establish[ing] the agreement of the parties regarding” their interpretation”?[xiii] Or could the Accords even amount to a “subsequent agreement between the parties regarding the interpretation” of those treaties or the application of their provisions?[xiv]

We do not take positions on any of these issues here, other than to note that, as ever in international space law and politics, there are many more questions than answers.

Final comments

Per Article 20 of the Moon Agreement, Saudi Arabia’s withdrawal will take effect on 5 January 2024. A lot can happen between now and then: we expect that by the time that Saudi Arabia’s withdrawal is completed, the fate of the Moon Agreement will have been decided by the actions of India, France, Mexico, and Australia. Withdrawal by Mexico or Australia, or formal withdrawal of signature by India or France, would be fatal to the Moon Agreement’s future.
Although we see the Moon Agreement as a promising legal instrument and attractive framework for lunar governance, we cannot overlook the fact that many States have decided to plot a different course. And developments at the international level increasingly favor non-binding instruments over ‘hard law’; States are increasingly hesitant to subject themselves to binding legal instruments.
However, non-binding instruments are often a stepping stone for the development of binding instruments. This is exactly what happened in the early days of international space law: a non-binding resolution adopted by the General Assembly in 1963 formed the basis for the Outer Space Treaty, with some provisions carried over verbatim. It is not impossible to imagine the same thing happening with the Accords, with a binding, multilateral treaty being the end result. Given this trajectory, perhaps the time has come to end the debate, cut the final threads, and close the book on the Moon Agreement once and for all.


Mr. Stefan-Michael Wedenig, DCL candidate, Executive Director, Institute of Air and Space Law, McGill University
& Jack Wright Nelson, DCL candidate, Editor Annals Air & Space Law, Institute of Air and Space Law, McGill University

This commentary represents the personal views of the authors.

[i] Moon Agreement, Preamble.

[ii] The exact reasons for this low acceptance have been, and are still being debated by the academic community. A detailed discussion exceeds the scope of this commentary and we direct the reader to more detailed sources. See e.g Bin Cheng, “The Moon Treaty: Agreement Governing the Activities of States on the Moon and other Celestial Bodies within the Solar System other than the Earth”, Studies in International Space Law (Oxford: Oxford University Press, 1997)

[iii] These documents were brought to our attention via Cristian van Eijk’s excellent historical research of international space law.

[iv] VCLT, Preamble.

[v] We are grateful to Professor Ram Jakhu for bringing this point to our attention.

[vi] Moon Agreement, art 1. The Moon Agreement, like the other United Nations space treaties, does not conclusively define the term ‘celestial bodies’ and thus leaves room for interpretation.

[vii] Ibid, art 11 (2).

[viii] Ibid, arts 6, 11 (4).

[ix] Ibid, art 11(7).

[x] Fabio Tronchetti, “Legal aspects of space resource utilization” in Frans G von der Dunk & Fabio Tronchetti, eds, Handbook of Space Law, (Cheltenham: Edward Elgar Publishing, 2015) 769 at 783

[xi] Ibid.

[xii] Ibid at 784

[xiii] VCLT, art 31(3)(b).

[xiv] VCLT, art 31(3)(a).

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