2.1 China–US competition in the new era of lunar exploration: Security and safety concerns

The new round of lunar exploration and exploitation is characterized by the Artemis Program proposed by the US and its partners,Footnote ⁸ as well as the ILRS by China and Russia. The Artemis Program is committed to achieving ambitious goals, including landing the first woman and the first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before, and establishing the first long-term presence on the Moon.Footnote ⁹ The ILRS is defined as a scientific program by its sponsors. According to the ‘ILRS Guide for Partnership (V 1.0)’ released in June 2021, the ILRS is designed for multi-disciplinary and multi-purpose scientific research activities. These activities include exploration and use of the Moon, Moon-based observation, fundamental research experiments, and technology verification, with the capacity for long-term unmanned operation and the prospect of subsequent human presence.Footnote ¹⁰

A prominent feature of the new round is the China–US lunar competition. China and the US are not participating in each other’s lunar programs. Additionally, both parties intend to establish frameworks for their programs without coordinating with each other at the present stage. From the perspective of the US, China’s lunar activities are perceived as a serious threat to its interests. In July 2022, in an interview with the German newspaper ‘Bild’, NASA Administrator Bill Nelson criticized China, accusing it of seeking to militarize the Moon.Footnote ¹¹ In January 2023, in another interview, Administrator Nelson warned that ‘Beijing could establish a foothold and try to dominate the most resource-rich locations on the lunar surface – or even keep the US out.’Footnote ¹² Moreover, former commander of the International Space Station and Space Shuttle, Terry Virts, pointed out that ‘there is potentially mischief China can do on the Moon. If they set up infrastructure there they could potentially deny communications, for example.’Footnote ¹³

From China’s perspective, officials have stated that ‘there is no intent to militarize the Moon’Footnote ¹⁴ and called Nelson’s claims ‘reckless and false’.Footnote ¹⁵ Chinese official media also pointed out that the so-called ‘race’Footnote ¹⁶ to the Moon is a notion imagined by the US, in which China has no intention of participating.Footnote ¹⁷ However, China does not deny the existence of a new round of lunar exploration competition.Footnote ¹⁸ After the success of the Chang’e-6 mission to the far side of the Moon on 2 June 2024, observers noted that the pace of China’s ambitions has drawn concern from the US, which is China’s major rival in the new round of the ‘space race’.Footnote ¹⁹

A new era of lunar exploration and exploitation has begun. Whether acknowledged or not, this new phase is characterized by competition (if not termed as a ‘race’) between the major participants, namely China and the US.

Several new characteristics distinguish the current lunar activities from those of the Cold War era. Firstly, both parties’ lunar programs are not solely focused on returning humans to the Moon but also aim to establish a framework for sustainable and cooperative lunar activities. To achieve this, their missions encompass both lunar orbit and lunar surface operations.Footnote ²⁰ Secondly, the new round of lunar exploration places a greater emphasis on the economic potential of the Moon, such as the extraction of lunar resources. The Artemis Program, spearheaded by the US, highlights collaboration with commercial and international partners.Footnote ²¹ This includes non-governmental enterprises, which are now considered crucial participants alongside traditional state actors. These non-governmental entities are primarily interested in commercial benefits from lunar activities, such as resource extraction.Footnote ²² Consequently, a stable legal framework to protect their rights to these benefits, including extracted lunar resources, is essential.Footnote ²³Thirdly, specific controversies regarding lunar regulations focus on two key aspects: the rules for extracting resources on the Moon and the establishment of safety zones.

The first controversy emerged with the adoption of the ‘Space Resource Exploration and Utilization Act’ (2015 Act) by the US,Footnote ²⁴ which authorizes US citizens to extract resources from celestial bodies.Footnote ²⁵ The Artemis Accords adopt a similar stance.Footnote ²⁶ The Outer Space Treaty mandates that outer space, including the Moon and other celestial bodies, be explored and utilized for the benefit of all countries. This has raised legal debates over whether US activities on space resource extraction comply with existing international law.Footnote ²⁷ China has not officially reacted to the US’s 2015 Act but has outlined its position on space resource extraction. In a document submitted in March 2024 to the Working Group on Legal Aspects of Space Resource Activities of the Legal Subcommittee of the COPUOS,Footnote ²⁸ China stated that space resource utilization is permissible but must comply with the 1967 Outer Space Treaty.Footnote ²⁹ Certain analysts believe this submission indicates a convergence between US and Chinese positions, recognizing the necessity and legality of space resource activities under the Outer Space Treaty for any long-term presence in space.Footnote ³⁰ The five-year work plan of the Working Group, agreed upon at the 61^st session of the LSC, aims to finalize a set of initially recommended principles for space resource activities for the Committee’s consideration and consensus in 2027.Footnote ³¹ However, creating a detailed international agreement on space resources is not part of this initial plan, though more detailed consensus is anticipated.

Resource exploitation is only one aspect of lunar exploration and exploitation. Many other complex issues, such as the establishment of safety zones, directly impact lunar security and safety. Controversies surrounding safety zones must be carefully addressed, and coordination between China and the US on these rules will be complex but necessary. Issues concerning safety zones are crucial for deconflicting lunar exploration, which will be analyzed in the following section.

Considering the China–US competition and the particularities of this new round of lunar exploration, the following aspects for preserving lunar security and safety should be emphasized:

Firstly, the aspect of demilitarization in lunar exploration needs to be addressed. In the context of China–US competition, military concerns surrounding the Moon are increasing. According to the ‘ILRS Guide for Partnership’, the ILRS is intended solely for scientific purposes, excluding military or commercial objectives.Footnote ³² However, China’s capability to operate on the lunar surface poses a potential threat to the security and safety of the US and its partners. While it is difficult to definitively assert that military conflicts on the Moon are unavoidable in the future, growing military interest in the Moon is evident. Furthermore, given that both parties have designed comprehensive lunar missions, military concerns are no longer confined to the lunar surface alone; both cislunar space and the lunar surface must be considered as a whole. This situation challenges the principles and rules established by existing international space treaties,Footnote ³³ which primarily focus on activities below the geostationary orbit, thereby posing potential conflict risks for the future.

Secondly, the aspect of deconfliction in lunar exploration must be considered. Currently, 54 states have shown interest in participating in US-sponsored lunar programs by signing the Artemis Accords.Footnote ³⁴ These Accords are a set of nonbinding principles designed to guide the conduct of states involved in the civil exploration and use of the Moon, Mars, comets, and asteroids.Footnote ³⁵ For the ILRS, several states, such as Belarus, Pakistan, Azerbaijan, Venezuela, South Africa, Egypt, Nicaragua, Thailand, and Serbia have committed to joining.Footnote ³⁶ Unlike the US, which has formulated the Artemis Accords to facilitate further negotiation of detailed rules among its partners,Footnote ³⁷ China and Russia have only proposed several fundamental principles for ILRS participants. It can be anticipated that as the ILRS program progresses, China and Russia will establish rules concerning cooperation under the ILRS.

However, the sponsors of the two lunar programs – the US for Artemis and China and Russia for the ILRS – have not joined each other’s initiatives. Since no existing international regime is currently capable of effectively addressing the emerging lunar activities,Footnote ³⁸ rules applying only to specific lunar programs will serve as the main legal basis to ensure orderly and safe operations on the Moon. The divergent operational rules applied to different lunar programs could lead to safety concerns in daily activities on the lunar surface. If the future ILRS rules conflict with the requirements of the Artemis Accords, tensions between these two competing camps will likely deepen, increasing the risk of conflicts.

2.2 China–US coordination: A crucial step in establishing rules for lunar security and safety

Stable legal instruments to prevent conflicts are crucial for all participants conducting activities on the Moon. While existing international space treaties have established various principles and rules, they remain insufficient to guarantee the security and safety of activities conducted on the Moon. This gap motivates participants to seek improvements or establish new rules. As the main players in the new wave of lunar activities, China and the US are obliged to find appropriate coordinating measures, even amidst competition.Footnote ³⁹

Among the five space treaties, the 1967 Outer Space Treaty and the 1979 Moon Agreement are particularly relevant to preserving the security and safety of lunar activities. The 1967 Outer Space Treaty, regarded by some as the Magna Carta of contemporary outer space law,Footnote ⁴⁰ stipulates a series of fundamental principles. These include the peaceful use of outer space,Footnote ⁴¹ the non-appropriation of outer space,Footnote ⁴² the ban on nuclear weapons or any other kinds of weapons of mass destruction in outer space,Footnote ⁴³ the exclusively peaceful use of the Moon and other celestial bodies,Footnote ⁴⁴ international responsibility for national space activities,Footnote ⁴⁵ the authorization and supervision of non-governmental space activities,Footnote ⁴⁶ international space cooperation,Footnote ⁴⁷ and the protection of the space environment.Footnote ⁴⁸ These principles are essential for guiding participants in lunar programs to conduct their activities on a basis of demilitarization and deconfliction. However, the treaty lacks detailed provisions for implementing these principles. Researchers have noted that the Outer Space Treaty possesses a unique character in international law, serving as the foundation for an interconnected framework of bilateral agreements between individual countries and intergovernmental organizations, as well as for several subsequent treaties.Footnote ⁴⁹ The signatories, including major spacefaring nations such as the US, China, and Russia, may exploit the ambiguity of these principles to interpret them in ways that align with their own interests, particularly when applying them to emerging domains. This could potentially lead to misunderstandings and conflicts.

The 1979 Moon Agreement, aims to define and develop the provisions of international instruments related to the Moon and other celestial bodies.Footnote ⁵⁰ Similar to other space treaties, the Moon Agreement further elaborates certain provisions of the Outer Space Treaty.Footnote ⁵¹ It elaborates on fundamental principles contained in the Outer Space Treaty, such as in Article 3, which provides more detailed regulations on the principle of ‘exclusively peaceful uses of the Moon’. Additionally, the Moon Agreement proposes the creation of an international regime, including appropriate procedures, to govern the exploitation of the natural resources of the Moon as such exploitation becomes feasible.Footnote ⁵² One purpose of this regime is to ensure the orderly and safe development of these resources.Footnote ⁵³

Despite offering clearer rules for preserving lunar security and safety, the Moon Agreement has been signed and ratified by a relatively small number of countries. As of now, major space-faring nations such as the US, China, and Russia have not signed the Moon Agreement.Footnote ⁵⁴ A widely acknowledged reason why major spacefaring nations rejected the Moon Agreement is its introduction of the Common Heritage of Mankind (CHM) principle in Article 11 – the first instance of this concept being explicitly incorporated into space law. CHM was seen as an evolution of the vague expression ‘province of all mankind’ found in the 1967 Outer Space Treaty.Footnote ⁵⁵ However, the precise meanings of both terms remain controversial.

An analysis of the Moon Agreement’s negotiation history reveals three primary interpretations of the CHM principle. The US viewed CHM and the ‘province of all mankind’ as essentially indistinguishable, interpreting them as an extension of the res communis principle in international law, which traditionally implies that a resource cannot be appropriated by states. The Soviet Union insisted on drawing a clear distinction between the two concepts.Footnote ⁵⁶ Less developed countries at the time collectively argued that they had the right to define international law as it applied to them, given that most existing legal frameworks had been established before they attained nationhood status. Regarding the definition of the CHM principle, they asserted that it granted all nations inherent rights to shared resources, which should be equitably distributed among them.Footnote ⁵⁷ With the development of the Law of the Sea and the Moon Agreement, the distinction between the two principles has become clearer, although no consensus has been fully reached.Footnote ⁵⁸ A prevailing view is that the term ‘province’ is associated with territorial responsibility and governance, implying a form of control rather than ownership or economic benefit. In contrast, ‘heritage’ is directly linked to property and ownership, emphasizing the collective entitlement of humanity to shared resources.Footnote ⁵⁹

To understand the meaning of the CHM principle in space activities, the Moon Agreement serves as the primary reference.Footnote ⁶⁰ Article 11 of the Moon Agreement establishes that the Moon and other celestial bodies are subject to a form of common ownership, requiring the mandatory sharing of benefits derived from any exploitation of celestial resources.Footnote ⁶¹ This means that any benefits gained from extracting natural resources must be shared internationally. Consequently, resource exploitation by commercial entities would be considered inappropriate unless their activities contribute to the common benefit of all humankind. However, the extent and mechanism of this benefit-sharing obligation remain undefined, leaving significant uncertainty about its practical implementation.Footnote ⁶² Furthermore, Article 11(5) of the Moon Agreement states that an international regime must be established to regulate the exploitation of lunar resources once such activities become feasible. Based on this provision and the CHM principle, there is an argument that harvesting lunar resources is prohibited unless conducted under an internationally agreed-upon framework specifically designed to govern their exploitation.Footnote ⁶³

The limitations of existing international space treaties highlight the urgent need for coordination between major spacefaring nations, particularly China and the US. However, this effort faces several significant challenges that must be addressed. China has initiated the ILRS, which is currently the only rival to the US’s Artemis Program. China advocates for negotiating a multilateral agreement through the COPUOS as the acceptable approach to addressing lunar activities.Footnote ⁶⁴ The US has formulated the Artemis Accords to facilitate further negotiation of detailed rules among its partners. The Artemis Accords are designed to foster international cooperation and prevent conflicts in space. They include principles such as conducting activities for peaceful purposes,Footnote ⁶⁵ sharing space policies and plans transparently,Footnote ⁶⁶ developing interoperable space systems to ensure cooperation among nations,Footnote ⁶⁷ providing emergency assistance to astronauts in distress,Footnote ⁶⁸ and planning for the safe disposal of spacecraft and management of orbital space debris.Footnote ⁶⁹ These principles are crucial for preserving lunar security and safety. Additionally, the Artemis Accords endorse the establishment of safety zones as a measure to avoid harmful interference, which is an existing obligation under the 1967 Outer Space Treaty.

When developing rules for lunar activities, each participant in the lunar competition aims to dominate the process.Footnote ⁷⁰ If we consider the commonly accepted ‘province of all mankind’ principle discussed above, along with Article I, Paragraph 1 of the Outer Space Treaty, the appropriate approach to ensuring that space governance reflects the interests of all humankind – rather than those of specific nations – would be to formulate a new international agreement or amend existing treaties, such as the Moon Agreement, through the UN platforms.Footnote ⁷¹ However, the failure of the Moon Agreement and the current work agenda of COPUOS suggest that the prospect of establishing a new international treaty in the near future is highly unlikely. Since the adoption of the Moon Agreement, no new legally binding space treaties have been created. Furthermore, while COPUOS has periodically considered the possibility of reviewing the Moon Agreement, it has not made any formal recommendations to the UN General Assembly regarding the revision of its terms, as stipulated in Article 18 of the treaty.Footnote ⁷² China’s advocacy for an international agreement is seen as a strategy to hinder the US’s progress in lunar exploration and to create opportunities to establish a China-centric legal framework for governing lunar activities, thereby setting precedents for other states.Footnote ⁷³ On the other hand, the Artemis Accords represent US-centric rules. Some believe that by implementing the Artemis Accords, the US could ensure its interpretation of international space law prevails and position itself as the licensing nation for most of the world’s space companies, effectively becoming the de facto gatekeeper to the Moon.Footnote ⁷⁴

Even though China–US competition is a key feature of the new era of lunar exploration, to promote the coordination of the two major players of lunar activities, is a crucial initial step to at the present stage preserve the security and safety of activities on the Moon. As indicated, it is impossible to establish a comprehensive multilateral agreement addressing lunar activities in the short term. The membership of COPUOS has more than doubled since 1975, making it very challenging to achieve consensus.Footnote ⁷⁵ Even if a treaty similar to the Moon Agreement could be adopted, it would likely face the same challenges without the participation of major space-faring states, resulting in another ineffective agreement concerning the Moon. Given these constraints, alternative legal approaches must be pursued to address immediate concerns. Furthermore, there are feasible ways to facilitate this coordination. The reasons are illustrated as follows:

Firstly, most principles in the Artemis Accords are rooted in existing international space treaties and are also accepted by China and its partners in the ILRS program. These include principles such as conducting lunar activities for peaceful purposes, avoiding harmful interference, and fostering lunar cooperation.Footnote ⁷⁶ As the ILRS program progresses, formal legal regimes will be established. It is expected that more principles from existing international space treaties, which are included in the Artemis Accords, will also be incorporated into the ILRS legal framework. This shared foundation will provide a strong basis for promoting further coordination between China and the US.

Secondly, states participating in both the Artemis Program and the ILRS could play a crucial role in improving US–China relations and facilitating coordination in rule-making for lunar activities. As both initiatives continue to expand, more states, international organizations, and non-governmental entities are becoming involved. As of now, more than 50 states have signed the Artemis Accords, demonstrating widespread international support for the US-led initiative. On the other hand, the ILRS has attracted nearly 20 national governments and international organizations, along with over 40 non-governmental entities, which have signed cooperation agreements with China.Footnote ⁷⁷ Notably, Thailand holds a unique position as the only country that has signed agreements with both the Artemis Program and the ILRS.Footnote ⁷⁸ Similarly, Bahrain has signed agreements with China covering lunar and deep space exploration,Footnote ⁷⁹ Bangladesh and Peru, as members of the Asia-Pacific Space Cooperation Organization – a regional entity backed by China – participates in the ILRS through the organization.Footnote ⁸⁰ The growing number of countries with a ‘dual identity’ in both lunar programs could potentially ease coordination efforts between the US and China.Footnote ⁸¹

To sum up, the competition between China and the US is a significant characteristic of the new era of lunar exploration. China and the US are not like-minded states and hold different opinions on creating rules for lunar activities. However, as analyzed, coordination between China and the US on crucial rules is essential to preserve lunar security and safety in the absence of comprehensive international regulations. From China’s perspective, taking measures to coordinate with the US is an effective way to address misunderstandings about China’s lunar activities, particularly among the states participating in the Artemis program.

3.1 The exclusively peaceful uses of the Moon

The 1967 Outer Space Treaty in various sections refers to the use of outer space for peaceful purposes, yet it does not explicitly define ‘peaceful’. According to subsequent practices, the term ‘peaceful purposes’ is generally interpreted as ‘non-aggressive’ rather than ‘non-military’.Footnote ⁸² Article IV, paragraph 2 of the Outer Space Treaty, for the first time, pairs ‘exclusively’ with ‘peaceful purposes’. It has been suggested that this wording allows no room for any military use, even if non-aggressive.Footnote ⁸³ However, the same paragraph lists specific prohibitions of military activities on the Moon and other celestial bodies, such as establishing military bases, installations, and fortifications; testing any type of weapons; and conducting military manoeuvres. Moreover, the use of military personnel for scientific research or other peaceful purposes, as well as the use of equipment or facilities necessary for the peaceful exploration of the Moon and other celestial bodies, are explicitly allowed as exceptions. This raises the question of whether Article IV, Paragraph 2, provides a comprehensive and exhaustive list of prohibited military activities, leaving room for differing interpretations.

The Vienna Convention on the Law of TreatiesFootnote ⁸⁴ mandates that treaty interpretation be conducted in good faith, adhering to the ordinary meaning of the terms within their context and in light of the treaty’s object and purpose.Footnote ⁸⁵ When the application of these principles under Article 31 results in ambiguity, obscurity, or an interpretation that is manifestly absurd or unreasonable, supplementary means of interpretation may be employed. These include the treaty’s preparatory work and the circumstances surrounding its conclusion, either to confirm the intended meaning or to resolve uncertainties in interpretation.Footnote ⁸⁶ Applying these principles to Article IV, Paragraph 2 of the Outer Space Treaty, the inclusion of the term exclusively suggests that the list of prohibited military activities should not be considered exhaustive. This is particularly relevant given that the Outer Space Treaty, as a product of its time, could not have anticipated all potential future scenarios. Furthermore, the exclusively peaceful purposes clause in Article IV, Paragraph 2 was drafted with reference to the Antarctic Treaty.Footnote ⁸⁷ The latter’s phrase used for peaceful purposes only has been widely interpreted as requiring complete demilitarization of Antarctica.Footnote ⁸⁸ Given this precedent, it is reasonable to conclude that the drafters of the Outer Space Treaty intended to establish a framework for the demilitarization of the Moon and other celestial bodies.Footnote ⁸⁹

The 1979 Moon Agreement aims to establish the Moon as a completely demilitarized zone, similar to the Antarctic Treaty. Article 3 of the Moon Agreement explicitly prohibits any threat or use of force, or any other hostile act on the Moon. The expression of Article 3 is potential to make the ‘exclusively peaceful purposes’ clause of the Outer Space Treaty more clearly.Footnote ⁹⁰ As noted, since its opening for signature, only a limited number of states have ratified it, significantly limiting its relevance as a reflection of broadly accepted state practice.Footnote ⁹¹ Some argue that the primary reason for the treaty’s lack of acceptance was not the inclusion of the exclusively peaceful purposes clause.Footnote ⁹² Consequently, they suggest that Article 3 of the Moon Agreement, which elaborates on the provisions of the Outer Space Treaty, still holds potential for broader acceptance.Footnote ⁹³ However, in recent years, major spacefaring nations – particularly the US – have taken steps to minimize the Moon Agreement’s potential influence on future lunar exploration efforts. In April 2020, the White House issued the ‘Executive Order on Encouraging International Support for the Recovery and Use of Space Resources’, which explicitly rejects the notion that the Moon Agreement reflects or expresses customary international law.Footnote ⁹⁴ Consequently, from the US perspective, the provisions of the 1967 Outer Space Treaty remain the primary and sole binding international legal framework governing the exclusively peaceful use of the Moon.

As lunar activities continue to advance, the need for greater specificity in the interpretation of Article IV, Paragraph 2 of the Outer Space Treaty becomes increasingly evident. Based on the analysis above, it is widely acknowledged that the Moon should be demilitarized and used exclusively for peaceful purposes. However, further clarification and legal refinement are still required. Some commentators argue that permitting the use of military personnel, equipment, and facilities for scientific research and other peaceful exploration undermines the ‘exclusively peaceful purposes’ principle, as it is difficult to separate the military character of personnel or equipment from their stated civilian functions.Footnote ⁹⁵ As the distinction between military and civilian applications of space technology becomes increasingly blurred, this issue is likely to gain further prominence.Footnote ⁹⁶ Additionally, some scholars argue that under Article IV, Paragraph 2 of the Outer Space Treaty, certain activities on the Moon are not explicitly prohibited. These include the presence of facilities, provided they are not designated as military bases, installations, or fortifications, as well as activities that do not constitute ‘maneuvers’.Footnote ⁹⁷ While these activities may not be classified as explicitly military, they have the potential for dual-use applications. Therefore, it is necessary to consider how such activities, if conducted on the Moon, should be addressed within the framework of the ‘exclusively peaceful purposes’ principle.

For a long time after the Cold War, civil and commercial benefits were the primary drivers for space-faring nations to engage in space activities, making military concerns less prominent. Resource mining has been a major impetus for lunar exploration and exploitation.Footnote ⁹⁸ However, recent developments indicate an increasing military interest in the Moon, especially in the context of competition between China and the US. Analysts now view the Moon as an emerging military high ground and a potential conflict zone.Footnote ⁹⁹ Military presence is considered necessary to ensure the stability and security of lunar civil and commercial interests.Footnote ¹⁰⁰ The 1967 Outer Space Treaty allows for varying interpretations regarding military-related activities on the Moon, further contributing to these concerns. Additionally, the cislunar space strategies proposed by major space powers further challenge the existing Moon demilitarization rules. This growing militarization trend underscores the need to revisit and potentially strengthen international legal frameworks to prevent conflicts.

3.2 Cislunar space strategy and challenges to the Moon demilitarization rules

A report published by the US Air Force Research Laboratory in June 2021 suggests that military officials should prepare for operations in cislunar space.Footnote ¹⁰¹ A recent statement by Jared Isaacman, NASA’s next administrator appointed by President Donald Trump, further underscores the role of military officials in space. He suggested that the military might one day deploy troops in outer space,Footnote ¹⁰² a scenario that could potentially extend to cislunar space, which is part of outer space. Historically, the strategic value of cislunar space has been overlooked by space powers, and no specialized regulations have been formulated for this vast area. Cislunar space is part of outer space, so existing international space treaties apply.

Regarding demilitarization rules, national practices in implementing space treaties below Earth’s geosynchronous orbit illustrate that the military use of outer space for non-aggressive purposes has become a widely accepted norm. Furthermore, Article IV, Paragraph 1 of the 1967 Outer Space Treaty prohibits only the placement, installation, and stationing of objects carrying nuclear weapons or other weapons of mass destruction in orbit around the Earth or in outer space. Conventional weapons, military satellites, and other objects with attack capabilities are not mentioned in this provision.Footnote ¹⁰³

Factors in cislunar space that are beneficial for military purposes include: (i) Lunar orbit: The lunar orbit can host infrastructure such as satellites that provide communication and navigation services for missions in cislunar space.Footnote ¹⁰⁴ Similar to the situation on Earth, satellite communication and navigation around the Moon serve dual purposes, supporting both civilian and military operations. (ii) Lagrange pointsFootnote ¹⁰⁵: Lagrange points offer ideal locations for placing spacecraft for surveillance or as communication relays. Satellites positioned at Lagrange points can maintain communication with Earth while monitoring activities on the far side of the Moon.Footnote ¹⁰⁶ The success of China’s Chang’e-4 mission, which was the first spacecraft to land on the Moon’s far side, has raised concerns in the US.Footnote ¹⁰⁷ This achievement allows China to conduct scientific, military, or other activities without observation or interference.Footnote ¹⁰⁸ Consequently, developing monitoring capabilities at Lagrange points holds strategic and military significance for the US and other space-faring nations.

Additionally, activities conducted at lunar bases have the potential to contribute to military purposes in cislunar space, which may breach the principle of ‘exclusively peaceful purposes’ stipulated by the 1967 Outer Space Treaty. For example, the resources obtained from these bases could support military activities in cislunar space, even if the bases are owned and operated for purely civil purposes. One of the goals of the Defense Advanced Research Projects Agency’s project, Novel Orbital and Moon Manufacturing, Materials, and Mass-efficient Design, is to study resources obtained from the Moon’s surface and their applications to future defense missions.Footnote ¹⁰⁹

So far, the US has announced two significant military ventures in cislunar space: the Cislunar Highway Patrol Satellite (CHPS) and the Defense Deep Space Sentinel (D2S2). CHPS is a spaceflight experiment designed to demonstrate foundational space domain awareness capabilities within the cislunar regime.Footnote ¹¹⁰ D2S2 is a highly manoeuvrable spacecraft capable of conducting ‘rendezvous/proximity operations’, as well as ‘space object removal and recovery’, and other applications in defensive space operations.Footnote ¹¹¹ As lunar exploration and exploitation progress, it is anticipated that more military plans for cislunar space will be developed by space-faring nations.

The US military’s strategic plans for cislunar space encompass the following key considerations: (i) Trust issues with China: The US military is concerned that China may not pursue only peaceful aims and could leverage its lunar program for both economic and military advantages.Footnote ¹¹² Therefore, the US must maintain comprehensive awareness capacities in cislunar space to monitor all potential interferences. (ii) Protection of space assets: To ensure the security of US space assets on the lunar surface, in cislunar space, and even in Earth’s orbit,Footnote ¹¹³ the US needs to develop both attack and defense capacities in cislunar space.

Lunar operations have never been more prominent in military planning than they are now.Footnote ¹¹⁴ As analyzed, activities in cislunar space and on the lunar surface will inevitably interact. The military strategy for cislunar space aims to protect activities on the lunar surface, while operations on the lunar surface could potentially support military endeavors in cislunar space. This interaction further diminishes the effectiveness of Article IV of the 1967 Outer Space Treaty, which seeks to demilitarize operations on the lunar surface. This introduces uncertainty into the future of lunar exploration and exploitation. Moreover, the cislunar space military strategy introduces new risks in competing for limited resources in this area, such as the Lagrange points. To avoid potential conflicts, reasonable rules need to be coordinated among the main participants in lunar exploration.

4.1 The rationality to establish safety zones on the Moon

Article IX of the 1967 Outer Space Treaty stipulates that space activities should be guided by the principles of cooperation and mutual assistance. It requires that states conduct their activities in outer space, including on the Moon and other celestial bodies, with due regard to the interests of all other parties. If space activities are likely to cause potentially harmful interference with other activities, the relevant states must undertake appropriate international consultations before proceeding. Additionally, states that have reason to believe their activities might cause harmful interference can request consultations concerning these activities. The principles of cooperation, mutual assistance, and due regard to others’ interests outlined in this provision are somewhat ambiguous, allowing states parties considerable flexibility in their implementation.Footnote ¹¹⁵ Regarding the obligation to avoid harmful interference, Article IX mandates consultations but does not preclude other necessary measures.

The principles and obligations of due regard and consultation to avoid harmful interferences in space activities form the legal basis for establishing safety zones on the Moon. According to the Artemis Accords, signatories are required to provide notification of their activities and coordinate with relevant actors to prevent harmful interference within designated areas, referred to as safety zones.Footnote ¹¹⁶ Some researchers contend that safety zones are necessary, practical, and compliant with existing international law.Footnote ¹¹⁷

The concept of safety zones is not new. During the Cold War era, safety zones were primarily discussed as a means of conflict deterrence.Footnote ¹¹⁸ In maritime contexts, safety zones are defined as areas extending a reasonable distance around a facility to ensure its safety by promoting safe navigation in its vicinity.Footnote ¹¹⁹ The ‘Building Blocks for the Development of an International Framework on Space Resource Activities’, released by the Hague International Space Resources Governance Working Group in 2019 (the Hague Building Blocks),Footnote ¹²⁰ suggests that states and international organizations responsible for space resource activities should be allowed to establish safety zones or other area-based safety measures to ensure safety and prevent harmful interference with those activities.Footnote ¹²¹

By incorporating technological and hazard-based considerations into space activities, creating safety zones is seen as an appropriate measure for minimizing risks. On the Moon, two key safety risks are particularly notable due to its low gravity and lack of atmosphere: (i) Lunar dust from landing, launching, and surface operations can indiscriminately damage other spacecraft over long distances. (ii) The embedded energy in spacecraft fuel and energy systems can create an explosion hazard with far-reaching impacts.Footnote ¹²²

In the absence of an international consensus on a lunar legal framework, safety zones are established by the operators of specific installations or facilities on the lunar surface, operating on a ‘first come, first served’ basis. These zones occupy territory on the lunar surface, and activities within them are subject to safety restrictions. Consequently, many critics argue that safety zones could become areas of national influence or de facto appropriation, violating Articles I and II of the 1967 Outer Space Treaty.Footnote ¹²³ While the Artemis Accords emphasize the importance of compliance with international space treaties,Footnote ¹²⁴ they also explicitly affirm that their provisions do not intend to contravene Article II of the Outer Space Treaty.Footnote ¹²⁵ To avoid breaching space treaty obligations, legal arrangements for safety zones must be carefully elaborated.

To establish and operate safety zones without infringing on international obligations, the following fundamental criteria should be adhered to: (i) Ensure transparency in the creation and maintenance of safety zones. (ii) Ensure that the establishment or operation of a zone does not grant sovereign rights. (iii) Ensure that fundamental space rules, particularly the established principles from international space law such as the 1967 Outer Space Treaty, are equally applicable both inside and outside of safety zones.Footnote ¹²⁶ In other words, the freedom to explore and use outer space provided by the 1967 Outer Space Treaty is not absolute and must be balanced against the legitimate interests of other states.Footnote ¹²⁷ Therefore, even if the creation of safety zones is necessary to preserve safe operations on the Moon, rules applicable to safety zones and all space activities must be strictly observed.

Establishing safety zones is one of several possible ways to implement Article IX of the Outer Space Treaty.Footnote ¹²⁸ Given the harsh natural environment on the Moon, safety zones are seen as an effective measure to ensure the safe and sustainable development of lunar programs. China and Russia, as competitors to the US, might find no better way to avoid harmful interference when operating on the Moon within the context of the ILRS. It is highly probable that China and Russia will establish safety zones around the ILRS. The fundamental criteria for safety zones should be uniformly applicable. However, since China and Russia are not signatories to the Artemis Accords, they are not required to follow the detailed rules for establishing and operating safety zones that apply to Artemis partners.Footnote ¹²⁹ This discrepancy could lead to conflicts, which warrant careful attention.

4.2 Safety zones rules and the necessity of harmonization

The Hague Building Blocks outline several fundamental rules that must be recognized by states or international organizations that establish safety zones or other area-based measures. Specifically, safety measures must not impede the free access of personnel, vehicles, and equipment of other operators to any area of outer space, in accordance with international law.Footnote ¹³⁰ Additionally, states or international organizations may restrict access for a limited period, provided that timely public notice is given, detailing the reasons for such restrictions.Footnote ¹³¹

The Artemis Accords embrace a similar approach to the Hague Building Blocks regarding the establishment of safety zones, providing more detailed guidelines. These guidelines cover aspects such as the size and scope of a safety zone, the nature and existence of a safety zone, and rules of behavior within safety zones. However, further coordination is required regarding the size, scope, nature, and establishment of safety zones, as well as the specific behavioral guidelines governing activities within these zones.

First, regarding the size and scope of a safety zone, the Artemis Accords propose that these should reflect the nature of the operation and the environment in which it is conducted. Furthermore, the size and scope should be determined reasonably, leveraging commonly accepted scientific and engineering principles.Footnote ¹³² In comparison, the law of the sea authorizes a relatively fixed size for safety zones around artificial islands, installations, and structures located in the exclusive economic zone.Footnote ¹³³ The proposal in the Artemis Accords is more ambiguous, relying on the nature of the operations, the environment, and commonly accepted scientific and engineering principles as essential criteria. For non-signatories of the Accords, it is uncertain whether these criteria will be accepted. Even if they are acknowledged, several issues need to be addressed, including which authority is qualified to evaluate the operation’s nature and environment, what specific scientific and engineering principles must be considered, and whether there are any other impacting factors that need to be taken into account.

Second, concerning the nature and existence of a safety zone, the Artemis Accords indicate that the size and scope of a safety zone should be adjusted over time to correspond with the status of relevant operations. Furthermore, safety zones are ultimately temporary and should be terminated once the relevant operations cease.Footnote ¹³⁴ Rules confirming the nature and existence of a safety zone are beneficial for ensuring operators’ compliance with Article II of the 1967 Outer Space Treaty. All operators on the Moon, whether signatories of the Artemis Accords or not, must accept these rules. For non-signatories, establishing harmonized standards to determine changes in the status of relevant operations would be more reliable.

Third, concerning rules of behavior in safety zones, the Artemis Accords oblige signatories to respect reasonable safety zones to avoid harmful interference with operations by providing prior notification to and coordinating with each other before conducting operations within a safety zone.Footnote ¹³⁵ The requirements for notification and coordination are supported by Article IX of the Outer Space Treaty. However, due to the lack of details, it is questionable whether these procedures are sufficient in practice. Safety zones are established to prevent harmful interference; they could encompass anything from a narrow radius around a space object to large swathes of space where access would be temporarily restricted.Footnote ¹³⁶ As indicated in the Hague Building Blocks, one state may exclude or restrict other states or their nationals within safety zones for security and safety reasons. However, the legality of these safety zones is determined by the extent and manner of such exclusions and restrictions. Therefore, for the US and its Artemis partners, as well as other non-signatories, formulating clear and reasonable rules of behavior in safety zones is not only essential to ensure regular lunar operations but also necessary to fulfill international obligations.

Rules not contained in the Artemis Accords but relevant to lunar activities must also be emphasized. For instance, regulations addressing overlapping safety zones and dispute settlements between different entities are necessary. The south pole of the Moon holds the majority of relatively accessible ice, and the race to operate there has already begun.Footnote ¹³⁷ While it is difficult to predict immediate crowding at the lunar south pole, the overlap of safety zones between different operators is a possibility. For countries involved in the Moon race, the pioneer establishing a safety zone at the lunar south pole will gain priority. However, in the long term, formulating appropriate rules and mechanisms to prevent and resolve potential overlaps and disputes will be the optimal choice to safeguard the safe and sustainable development of lunar activities.

In summary, creating safety zones on the Moon is a necessary step to implement Article IX of the Outer Space Treaty. However, this action could potentially breach other provisions of the Outer Space Treaty (Articles I and II), making it essential to establish clear criteria for safety zones to ensure their legality. The US’s competitors on the Moon, namely China and Russia, have not accepted the Artemis Accords as signatories. Despite this, China and Russia may find no better measures than creating safety zones to avoid harmful interference. Safety zones could potentially be accepted by all lunar operators. Therefore, it is crucial to formulate specific rules concerning the size, scope, nature, existence, management, and dispute settlement of safety zones that are agreed upon by all participants in lunar activities.

5.1 Participating in the creation of international norms, rules, and principles for the demilitarized use of the Moon

In 2008, China and Russia submitted a ‘Draft Treaty on the Prevention of Placement of Weapons in Outer Space, the Threat or Use of Force against Outer Space Objects’ (PPWT) to the Conference on Disarmament (CD).Footnote ¹³⁸ A revised version was submitted in 2014.Footnote ¹³⁹ The PPWT aims to fill the gaps of the 1967 Outer Space Treaty by proposing to prevent the placement of any type of weapons in outer space, including on the Moon and other celestial bodies. Additionally, the PPWT stipulates prohibiting any actions involving the threat or use of force against space objects.Footnote ¹⁴⁰ However, the PPWT lacks consensus among significant space powers, with the US being the major objector.Footnote ¹⁴¹ Conversely, the European Union initiated a non-legally binding model, the ‘Draft Code of Conduct for Outer Space Activities’ (ICoC). The first version of the ICoC was published in 2008,Footnote ¹⁴² and the latest draft was published in March 2014.Footnote ¹⁴³ The ICoC aims to enhance the safety, security, and sustainability of all outer space activities related to space objects and the space environment.Footnote ¹⁴⁴

The debate over whether a hard law or soft law model is better to prevent the arms race and weaponization in outer space was a key point of contention.Footnote ¹⁴⁵ However, after the latest versions of the PPWT and ICoC were proposed in 2014, the debate seemed to be suspended. Recently, the idea of reducing space threats through norms, rules, and responsible behaviors was proposed by the United Kingdom,Footnote ¹⁴⁶ bringing renewed emphasis on the model for governing space military activities and weaponization.

The ‘Reducing Space Threats through Norms, Rules and Principles of Responsible Behaviours’ resolution, adopted by the UN General Assembly, calls on all Member States to work toward a shared understanding of measures to mitigate threats to space systems. Its primary objective is to ensure that outer space remains a peaceful, safe, stable, and sustainable environment – free from conflict and an arms race – for the benefit of all.Footnote ¹⁴⁷ Pursuant to the UN General Assembly Resolution, an Open-Ended Working Group (OEWG) was convened to develop recommendations on possible norms, rules, and principles of responsible behavior related to space security.Footnote ¹⁴⁸ The OEWG held four substantive sessions: the first session reviewed existing legal frameworks and assessed the current state of outer space security; the second session examined current and potential threats to space systems, including those arising from Earth-based activities; the third session explored possible norms, rules, and principles to enhance space security and mitigate threats; the fourth session aimed to consolidate recommendations and draft a final report for the UN General Assembly.Footnote ¹⁴⁹ Despite extensive discussions, the OEWG failed to reach a consensus on its final report.Footnote ¹⁵⁰ However, its work remains a significant contribution to advancing space security and preventing an arms race in outer space.Footnote ¹⁵¹ In 2023, the UN General Assembly approved the establishment of a new Open-Ended Working Group to further develop the concept of responsible behaviors in space and make recommendations on preventing an arms race. This new OEWG is tasked with submitting its report to the General Assembly at its 81^st session and is required to adopt its final conclusions and recommendations by consensus.Footnote ¹⁵²

Compared to the PPWT, the proposal for responsible behaviors is more comprehensive and flexible. Some have put forward the idea that like-minded states should first reach a consensus on the fundamental criteria of responsible behavior, then promote these criteria to other states and non-governmental space entities.Footnote ¹⁵³ If major space powers and commercial space entities accept them, universally applicable norms, rules, and principles can eventually be established.

China continues to advocate for negotiating a legally binding treaty based on the PPWT to prevent an arms race and weaponization in outer space.Footnote ¹⁵⁴ Additionally, China is concerned that the binary distinction between responsible and irresponsible behaviors in outer space could be used as a political tool.Footnote ¹⁵⁵ Consequently, China voted against the UNGA resolution on responsible behaviors.Footnote ¹⁵⁶

In October 2023, the First Committee of the UN voted to support the US and its allies, as well as China and Russia, in organizing two working groups to develop different measures for preserving space security.Footnote ¹⁵⁷ The working group led by the US and its allies will continue negotiating norms of responsible behavior, while the China/Russia-led working group will focus on a legally binding model to prevent the deployment of space weapons.Footnote ¹⁵⁸ These parallel paths further confirm the coexistence of hard law and soft law models.

The particularities of the new round of lunar exploration and exploitation, such as the participation of non-governmental entities and the emphasis on commercial benefits, demand a stable legal regime to ensure safe and sustainable operations on the Moon. However, various factors make the creation of a new treaty unlikely in the near future. The responsible behaviour proposal aims to establish a soft law framework as a first step, with the creation of legally binding instruments as a long-term goal. This does not contradict China’s proposal of the PPWT. China has acknowledged that the responsible behaviour proposal can be included as an agenda item for the Prevention of an Arms Race in Outer Space and has expressed its intention to participate in further discussions.Footnote ¹⁵⁹

It is recommended that China, as a significant player in lunar activities, both improve the PPWT and actively engage in creating norms, rules, and principles of responsible behaviour for lunar exploration and use. As indicated, space powers have already identified cislunar space as a strategic military area. While conducting military activities in cislunar space may not violate existing space treaties, these activities are relevant to the safe and sustainable development of lunar surface operations. Consequently, clarifying fundamental principles through the PPWT and establishing norms, rules, and principles of responsible behaviour in cislunar space will help prevent conflicts and arms races. Additionally, some activities are not explicitly prohibited on the Moon under the existing legal framework, which may deviate from the principle of exclusively peaceful use and needs to be addressed and evaluated by the criteria of responsible behaviour.

5.2 Coordinating with the US on harmonized safety zones rules for lunar operations

Once lunar programs are established by the US and China, harmonized deconfliction rules will become urgent, with the most significant being the rules for safety zones. In 2011, the US Congress included a passage in an appropriations bill, known as the Wolf Amendment,Footnote ¹⁶⁰ forbidding NASA from cooperating with China due to fears of technological theft or espionage.Footnote ¹⁶¹ However, the Wolf Amendment does not explicitly ban all cooperation between NASA and Chinese counterparts but rather prohibits NASA from using government funds to cooperate with China without direct Congressional approval.Footnote ¹⁶² Some argue that without cooperation between the US and China, space cannot be safe.Footnote ¹⁶³ The two countries need to set aside their mistrust to establish harmonized rules necessary for ensuring safety lunar operations.

China is advised to coordinate with the US to formulate rules on enhancing the transparency of lunar operations and activities in safety zones. Transparency is fundamental for creating and maintaining safety zones to avoid harmful interference in daily activities and is a measure to safeguard the security, safety, and sustainability of space activities.Footnote ¹⁶⁴ Both the US and China support establishing transparency and confidence-building measures in outer space,Footnote ¹⁶⁵ providing opportunities for further negotiation concerning safety zone rules.

The US, within the framework of the Artemis Accords, will establish detailed rules concerning safety zones with its partners. To ensure the safe and sustainable implementation of lunar activities, it is anticipated that China and Russia will take similar steps under the ILRS. Fragmented deconfliction rules of lunar programs from different camps could result in collisions. Therefore, it is recommended that China coordinate with the US to harmonize the details of safety zones, including size and scope, nature and existence, rules of behaviour, and dispute settlement measures. Formulating these details will take time, even with a China–US coordinating system in place. However, actively coordinating with its rival on the Moon will benefit China by reducing misunderstandings of Chinese lunar activities and lowering the possibility of conflicts on the Moon.

The UNCOPUOS has discussed the dangers of unilateral regulation of lunar activities and the advantages of international regulation for ensuring compliance with the Outer Space Treaty.Footnote ¹⁶⁶ However, the Artemis Accords, criticized as unilateral measures, cannot be judged to breach existing international law. As previously noted, by sponsoring the Artemis Accords, the US aims to build a US-centric regime of governance in lunar exploration and exploitation.Footnote ¹⁶⁷ In contrast, some observers suggest that, although China and Russia have expressed support for developing an international regime through the COPUOS, they are unlikely to accept commitments that might constrain their strategic interests on the Moon.Footnote ¹⁶⁸ Instead, they appear to be pursuing the creation of a Sino-Russian-centered governance model – through multilateral cooperation platforms – as a counterweight to the Artemis Accords.Footnote ¹⁶⁹

To avoid conflicts on the Moon and ensure lunar security and safety, neither a US-centric nor a Sino-Russian-centric regime will benefit humanity. Coordination between them is necessary as a starting point. Concerning demilitarization rules surrounding lunar activities, establishing norms, rules, and principles of responsible behavior in cislunar space and on the Moon can be a transitional measure until an international treaty is adopted. While creating safety zones on the Moon may not be the best choice to implement Article IX of the 1967 Outer Space Treaty, with the development of lunar programs, safety zones may become the earliest practice of lunar deconfliction. In this case, effective coordination on specific rules between space powers that can establish a presence on the Moon, namely the US and China/Russia, is essential. Furthermore, coordination between these competitive camps is crucial for promoting further negotiations under the UNCOPUOS.