War Laws In Space: What Rules Apply?

The laws of war are a component of international law that regulate the conditions for initiating war and the conduct of hostilities. The laws of war define sovereignty and nationhood, states and territories, occupation, and other critical terms of law. The laws of war are considered distinct from other bodies of law, such as the domestic law of a particular belligerent to a conflict.

The laws of war are binding not only upon states but also upon individuals, especially members of their armed forces. Parties are bound by the laws of war as long as such compliance does not interfere with achieving legitimate military goals.

The prospect of armed conflict in outer space appears to be growing. Beyond geopolitical tensions between space powers, countries' reliance on space for national security purposes and the proliferation of counterspace capabilities are contributing to the risk of space war.

International humanitarian law (IHL) is never dependent on the lawfulness of the decision to employ force. Rather, its applicability is a question of fact—specifically, whether the situation at hand amounts to an international armed conflict (IAC) or non-international armed conflict (NIAC). If an IAC or NIAC has begun, all operations with a nexus to the conflict are subject to IHL's obligations, prohibitions, and restrictions.

The Woomera Manual on the International Law of Military Space Operations is an international collaborative effort to develop what is hoped to become the definitive document on military and security law as it applies to space. The project is named after the Woomera township in South Australia, which has a long association with both Australian and multinational military space operations.

While the Woomera Manual is not binding or authoritative law, it does provide critical guidance for policymakers as they draft and consider new legislation or international agreements.

Jus ad bellum

Under modern public international law, the UN Charter establishes the fundamental rules of jus ad bellum. Article 2, paragraph 4 of the Charter states:

> All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any other manner inconsistent with the purposes of the United Nations.

Article 51 of the UN Charter clarifies:

> Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations.

An international agreement limiting the justifiable reasons for a country to declare war on another is concerned with jus ad bellum. In addition to bilateral non-aggression pacts, the 20th century saw multilateral treaties that placed entirely new restrictions on going to war. The Kellogg-Briand Pact, the London Charter, and the United Nations Charter are notable examples.

The principle of right authority suggests that a war is just only if waged by a legitimate authority. This authority is rooted in the notion of state sovereignty. According to the principle of right intention, the aim of war must not be to pursue narrowly defined national interests, but rather to re-establish a just peace. The principle of last resort stipulates that all non-violent options must be exhausted before the use of force can be justified.

The rules of the UN Charter are generally considered to apply in outer space. Article 2 (4) of the Charter is sufficiently broad to cover the illegal use of force in outer space, despite the lack of conventional borders in the res communis environment. This is because Article 2 (4) prohibits the use of force "in any other manner inconsistent with the Purposes of the United Nations", which include maintaining international peace and security.

The Outer Space Treaty (OST) states that outer space use shall be in accordance with international law and the UN Charter. The jus cogens use of force prohibition, as found in the UN Charter and customary international law, thus also applies to outer space use.

The "launching states" retain sovereignty over their space objects under international law, similar to the concept of the "flag state" in maritime law. Since space objects remain under the sovereign control of their respective launching states, the use of force against another state's space object qualifies as a prohibited use of force.

The lack of sufficient normative clarity regarding the legality of using force in outer space contains the risk that states may abuse existing legal gaps or act in ways that others consider unlawful. Since it is unlikely that the major global space powers will agree on any new space treaty in the foreseeable future, other means of restricting the use of force in outer space should be considered.

Customary international space law is frequently formed through soft law, such as UN General Assembly resolutions. These resolutions can be considered as authoritative interpretations of the UN Charter in the context of outer space and contribute to the formation of customary international law regarding the prohibition of using force in outer space.

Although the applicability of international humanitarian law (IHL) to space operations carried out during an armed conflict triggered by terrestrial military force is indisputable, whether space operations can alone initiate a state of armed conflict is a more challenging question. For hostilities in space to rise to the level of a non-international armed conflict (NIAC), a threshold of "intensity" must be met.

The principle of distinction, considered a "cardinal principle" of IHL, requires parties to an armed conflict to distinguish between combatants and civilians, and between military objectives and civilian objects. The common practice of using civilian launch systems to place military satellites into orbit offers a straightforward case study of qualification as a military objective.

The growing commercialisation of space activities, the reliance of military forces on commercial space systems, and the dual-use nature of many space technologies will provide challenges in identifying military objectives and applying the principle of distinction during armed conflict in outer space.

Jus in bello

The laws governing jus in bello are found in various international treaties and agreements, including the Outer Space Treaty, the Geneva Conventions, and the Additional Protocol I (AP I) to the Geneva Conventions. These laws apply to all forms of warfare and weapons, including those used in outer space.

The principle of distinction is a cardinal principle of jus in bello, which requires parties to an armed conflict to distinguish between combatants and civilians, and between military objectives and civilian objects. This principle is reflected in Article 52(2) of AP I, which states that objects may only be attacked if they make an effective contribution to military action and their destruction offers a definite military advantage.

Another important concept in jus in bello is the prohibition on indiscriminate attacks, which is distinct from the prohibition on directly attacking civilians or civilian objects. Indiscriminate attacks demonstrate reckless disregard for civilian casualties or damage to civilian objects. This prohibition is formulated in Article 51(4) of AP I and is considered a norm of customary international law applicable in both international and non-international armed conflicts.

The issue of space debris is relevant to the prohibition on indiscriminate attacks. Space debris can be human-made or naturally occurring, and it can remain in orbit for a long time, posing unique problems. Some commentators argue that the use of kinetic weapons in outer space violates the prohibition on indiscriminate attacks because the effects of this method of attack cannot be limited as required by international law. However, this conclusion has been disputed, and the evaluation of this issue must consider the quantity and decaying timeline of the resulting debris.

The rule of proportionality is another customary norm of jus in bello, which prohibits any attack expected to cause excessive harm to civilians or civilian objects, regardless of whether the attack itself is discriminating. This rule requires a balance between the expected military advantage and the potential harm to civilians.

In the context of space warfare, the definition of an "attack" is important. An attack is defined as an "act of violence against the adversary, whether in offence or defence." Any military space operation that causes physical damage, whether in space or on Earth, amounts to an attack if the damage surpasses a de minimis threshold. However, there are grey areas regarding where to draw the line between space operations qualifying as an attack and those that do not.

In conclusion, jus in bello sets out the rules that should be followed during a war to ensure that it is conducted justly and lawfully. These rules include the principle of distinction, the prohibition on indiscriminate attacks, and the rule of proportionality. In the context of space warfare, the application of these rules can be complex and ambiguous, especially when considering the unique physics of space and the potential impact of space debris.

International humanitarian law

IHL, also known as the law of armed conflict, applies to situations amounting to an international armed conflict (IAC) or a non-international armed conflict (NIAC). It is not dependent on the lawfulness of the decision to employ force but rather on the factual determination of whether an armed conflict exists. This is clarified in Article III of the Outer Space Treaty, which states that the use of outer space shall be carried out "in accordance with international law," including IHL.

The applicability of IHL to space operations is further supported by the 1949 Geneva Conventions' reference to "any... armed conflict" and the International Court of Justice's (ICJ) 1986 Nuclear Weapons Advisory Opinion, which confirmed the applicability of IHL to all forms of warfare, without distinction based on the domain or methods of warfare. The United States Department of Defense Law of War Manual and the International Committee of the Red Cross (ICRC) also affirm that IHL regulates the conduct of hostilities, regardless of their location, including in outer space.

IHL imposes constraints on military operations conducted in the context of an armed conflict, including those carried out in or affecting outer space. It aims to protect civilian populations and objects during armed conflicts, as outlined in the principles of distinction, proportionality, and the obligation to take precautions to minimise harm to civilians. These rules apply to kinetic and non-kinetic military operations against space systems and require the consideration of potential incidental harm to civilians and civilian objects.

The challenge of identifying military objectives and applying the principle of distinction is particularly complex in space due to the dual-use nature of many space technologies and the commercialisation of space activities. The principle of distinction requires distinguishing between combatants and civilians, as well as between military objectives and civilian objects. In the context of space warfare, this can be difficult due to the use of civilian launch systems to place military satellites into orbit and the presence of hosted payloads, where military payloads are integrated with civilian satellites.

The prohibition on indiscriminate attacks, as outlined in Article 51(4) of Additional Protocol I (AP I), is another critical aspect of IHL applicable to space warfare. This prohibition is distinct from the ban on directly attacking civilians or civilian objects and focuses on the reckless disregard for potential consequences. The issue of space debris and its potential indiscriminate effects is central to this discussion. While the creation of space debris through kinetic strikes does not automatically violate IHL, States must take all feasible precautions to minimise incidental harm to civilians and civilian objects, which may include opting for less harmful alternatives to kinetic attacks on military satellites.

In conclusion, IHL plays a crucial role in regulating military operations in outer space by imposing constraints aimed at protecting civilians and civilian objects. However, the unique characteristics of space and the complexities of space warfare present significant challenges in interpreting and applying IHL principles. Efforts such as the Woomera Manual on the International Law of Military Space Operations aim to provide clarity and ensure the effective application of IHL in future conflicts involving outer space.

International treaties

Six international treaties have been negotiated to govern state behaviour in space:

• Partial Test Ban Treaty
• Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space, and Under Water
• Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (the "Outer Space Treaty")
• Agreement on the Rescue of Astronauts, the Return of Astronauts and the Return of Objects Launched into Outer Space
• Liability Convention (Convention on International Liability for Damage Caused by Space Objects)
• Registration Convention (Convention on Registration of Objects Launched into Outer Space)
• Agreement Governing the Activities of States on the Moon and Other Celestial Bodies (the "Moon Treaty")

The Rescue Agreement, the Liability Convention, and the Registration Convention elaborate on provisions of the Outer Space Treaty. Many consider the Moon Treaty to be a failed treaty due to its limited acceptance. However, some have pointed out that the limited membership of the Moon Treaty allows current signatory states to easily amend and update the treaty to keep up with the fast pace of technological development in space exploration.

In addition to the above treaties, the nations participating in the International Space Station have entered into the 1998 Agreement among the governments of Canada, Member States of the European Space Agency, Japan, the Russian Federation, and the United States. This agreement provides that NASA is the lead agency in coordinating the member states' contributions to and activities on the space station, and that each nation has jurisdiction over its own module(s). The agreement also covers the protection of intellectual property and procedures for criminal prosecution.

The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) and its Legal and Scientific and Technical Subcommittees are responsible for debating issues of international space law and policy. The United Nations Office for Outer Space Affairs (UNOOSA) serves as the secretariat of the committee and promotes "Access to Space for All" through various conferences and capacity-building programs.

The few international treaties that deal with outer space provide little regulation of modern space activities, including both military and commercial uses of space. As such, legal experts are now debating how Earth-bound laws might apply to wars in outer space and are developing a manual on military and security law as it applies to space: the Woomera Manual on the International Law of Military Space Operations. Although such manuals are not binding or authoritative, they do provide critical guidance to policymakers.

Customary international law

The applicability of IHL to space operations is not dependent on the lawfulness of the use of force but on the existence of an international or non-international armed conflict. This distinction is crucial, as it determines whether IHL's obligations, prohibitions, and restrictions come into force. The challenge lies in defining the threshold of "intensity" required for hostilities in space to escalate into an armed conflict, particularly in the context of non-international armed conflicts.

The concept of "attack" in IHL is pivotal, as it underpins various rules governing the protection of civilians and civilian objects. In the space context, an attack is defined as an "act of violence" against an adversary, encompassing both kinetic and non-kinetic means that cause physical damage or destruction. However, the line between what constitutes an attack and mere "acts of inconvenience" that result in temporary disruptions is less clear and remains a subject of debate.

The principle of distinction, a fundamental tenet of IHL, requires the differentiation between combatants and civilians, as well as military and civilian objects, during hostilities. In the context of space warfare, the challenge arises from the dual-use nature of many space objects, including satellites, which serve both civilian and military purposes. While these dual-use objects are generally considered legitimate military objectives, the potential humanitarian consequences of their disruption or destruction are significant.

The principles of proportionality and precaution come into play when assessing the legality of targeting dual-use satellites. Proportionality dictates that the anticipated collateral damage to civilians and civilian objects must not be excessive in relation to the concrete and direct military advantage anticipated from the attack. The principle of precaution mandates constant care to spare the civilian population and minimise incidental harm to civilians and civilian objects.

In conclusion, customary international law plays a vital role in regulating space-related activities, including military operations in outer space. While treaties provide a foundational framework, customary international law adapts to evolving challenges and fills gaps, ensuring that the dynamic domain of space remains governed by international legal principles.

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