NATO clearly identified outer space as the fifth military domain beside air, land, sea and cyberspace on November 2019, in response to expanding issues over protecting space assets from hostile intentions such as interference.1 As mentioned by the NATO Secretary General, Jens Stoltenberg, during a press conference in Brussels ‘this can allow NATO planners to make a request for allies to provide capabilities and services, such as satellite communications and data imagery’.2 There are about 2,000 satellites in the Earth’s orbit, at least half of them are owned and operated by NATO member States.3 Still, the Alliance does not possess its own space assets, and depends on the technologies of its members. This is a reality that space is becoming more and more important for military operations and missions. However, the Secretary General assured that NATO’s approach ‘… will remain defensive and fully in line with international law. NATO has no intention to put weapons in space. But we need to ensure our missions and operations have the right support.’4
These words illustrate the growing significance of outer space for the Alliance. Space is part of our daily life on Earth making space assets an integral part of national and international infrastructure. Moreover, space assets represent crucial elements to support military or humanitarian operations on Earth through remote sensing data, navigation, and telecommunications. Outer space can be used for peaceful purposes, but also in an aggressive way. As of now, the dependence on space assets is the reason why they are an attractive target to adversaries. Hence, space is becoming an essential tool for the Alliance’s deterrence and defence.5 It is crucial for NATO member countries that during the missions and operations they will undertake, they have the right support. Today, without satellites, modern warfare can no longer work. More and more countries are therefore developing new technologies such as Anti-Satellite (ASAT) weapons6 or cyberattacks to damage enemy satellites in case of ‘aggressive’ behaviour against space assets. Espionage should also be taken into account, just as in the case when a Russian satellite came close to the French-Italian satellite ‘Athena-Fidus’ used for military communications in October 2017.7 Another more recent example concerns a Russian inspector satellite which shifted its position in orbit to get closer to a United States (US) spy satellite.8 New space applications such as on-orbit servicing vehicles, due to their dual-use nature, might also represent a menace as they may be used in a hostile way against the space asset serviced.
The Legal Perspective of Outer Space
From a legal perspective, two substantial articles have to be stated when discussing the military use of outer space. First, Article III of the Outer Space Treaty (OST)9 stipulates that States shall carry on space activities in accordance with international law, including the Charter of the United Nations (UN). Then, Article IV paragraph 1 of the OST does not provide a complete demilitarization of outer space, but a denuclearization regime. In fact, States are unrestricted to deploy in outer space any type of military satellites and to use outer space for conventional weapons. Its paragraph 2 concerns the use of the Moon and other celestial bodies and it introduces full demilitarization of the Moon and other celestial bodies. Article IV denotes some ambiguities in the sense that it prohibits the use or placement in space of ‘nuclear weapons or any other kinds of weapons of mass destruction’ but it does not address the issue of conventional weapons. In this context, some activities carried out by States reveal the limits of Article IV such as the use of ASAT missiles10 by China, the US and more recently India.
States have the challenge to balance their commitment to international laws and the UN space treaties with protecting their space assets and interests in space activities from hostile action.
Linking Space Assets with States
In case of aggressive or hostile action against a space asset, the right of self-defence in outer space arises.11 Self-defence is a notion of international law linked to a State’s territory.12 Indeed, it refers to the right of a State to respond to armed attacks against its territory.13 In the first instance, one can argue that because outer space is an area beyond national jurisdiction, self-defence is not permitted in this environment. However, practice demonstrates that the right of self-defence is also in relation to the use of force against facilities and objects under the jurisdiction of a State, not just its physical territories.14 In this context, it is important to underscore the fact that an object launched into outer space, such as a satellite, must be registered by the launching State on an appropriate registry which it shall maintain.15 Thus, registration shapes a link between the registering State and the object registered that enables State to exercise its jurisdiction over its asset. Hence, States can legally conduct action in self-defence to respond to attacks against space objects that they have registered.16 One can highlight the fact that the right of self-defence in space is similar to the protection of vessels on the high seas or aircraft flying in international air spaces.17
Satellites can be ‘attacked’ using kinetic means, for instance ASAT, laser, microsatellites used as ‘explosive devices’, or non-kinetic means such as cyberattack, jamming, or interference. Hence, ‘attacking’ a space asset can reduce its functionality or destroy it, and it can create a strategic military advantage for the adversaries in case of conflict in outer space. These actions may represent an armed attack18 leading to the activation of the right of self-defence.
Given the crucial importance that space assets represent for military, social and economic systems, States seek to protect their assets against menaces that could damage or destroy them.19 States are placing the protection of space assets at the core of their defensive strategies and declaring their intention to act in self-defence in space if needed.20 In 2019 France presented a national space strategy with the establishment of a ‘Space Command’.21 In addition, the United States recently established the US Space Force as the sixth military branch.22
Jus Ad Bellum in Space
Nevertheless, the exercise of the right of self-defence in outer space represents a grey area of international law.23 First, States have to consider Article 2.4 of the UN Charter which prohibits the use of force in international relations. However, the UN Charter foresees two main exceptions to the prohibition on the use of force in international relations: (i) the use of force authorized by the Security Council under Chapter VII of the Charter; (ii) the individual or collective right of self-defence pursuant to Article 51 of the UN Charter. Both provisions are based on the jus ad bellum that is the circumstances under which it is lawful to employ military force.24
As mentioned, ‘jurisdiction’ over these objects is considered to correspond to ‘sovereignty’, and so the right of a State to defend objects under its sovereignty on Earth coherently extends to outer space. Thus, as long as states do not interfere in a hostile manner with the space assets of other states (thus violating of Article 2 (4) of the UN Charter) and do not station weapons of mass destruction or nuclear weapons in space, their right to act in self-defence in outer space pursuant to customary law and Article 51 of the UN Charter cannot be denied.
Some questions must be emphasized: do offensive or defensive actions in space warfare cause re-alignments to allied treaties? In other words, if a NATO Member State is attacked in space, does that automatically mean that NATO countries will come to its defence? According to Articles 5 and 6 of the North Atlantic Treaty, in case of an armed attack against one or more NATO Member States, it shall be considered as an attack against them all and consequently, the right of individual or collective self-defence shall be activated and shall assist the Party(ies). Here, it is admitted that the State jurisdiction is extended to its space assets, and in case of armed attack in space against one or several NATO Member States, the others may be able to support them.
These issues deserve new rules and much more attention from the international community. There is an imperative need to revisit the existing framework of international laws pertaining to space and State behaviour. It is necessary to reconsider the area of intervention, as outer space is a new ‘military domain’. In June, NATO defence ministers first announced the creation of a space strategy25, intending to protect satellites that are crucial for communication, navigation, early warning systems for rocket launches, and status reports in conflict zones. The North Atlantic Alliance could implement a policy similar on what already exists in the field of cyberspace operations. Indeed, NATO outlined that a cyberattack can, under certain circumstances, be considered a reason for activating Article 5 of the North Atlantic Treaty, thus activating the principle of collective defence.26 Triggering Article 5 could be also relevant in case of future hostile act in outer space.