Explainer: As Threat of Militarisation Rises, International Community Races to Set Standards for Responsible Behaviour in Outer Space Features
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Explainer: As Threat of Militarisation Rises, International Community Races to Set Standards for Responsible Behaviour in Outer Space

The past decades have seen a growing interest in, and utilisation of, outer space. Ease of access to space has increased alongside the rise of more affordable and small-scale technologies, and as a consequence space has become a congested and competitive environment. This has resulted in an increase in the number of nations with space ambitions, while the proliferation of commercial space platforms and space exploration has also grown, even leading to Elon Musk’s capabilities to support Ukraine in its defense against Russia’s invasion, and the new phenomenon of space tourism. 

No longer is the space domain reserved for the original space-faring nations — the United States, Russia and the emerging global power China. It is also causing the increased militarisation of space (‘arms race’) with a number nations having formed new military commands and armed forces (e.g. Space Command and Space Force: USA, UK, France) and NATO having declared space a war-fighting domain in 2019. 

The proliferation of space objects and debris is resulting in a growing risk of collision and damage, while the activities of certain nations (Russia, China) pose increased threats and risks of conflict. Western Allies have realized that they rely more and more on space for all military activities, including collective defence, crisis response, disaster relief, and counterterrorism, and depend on information delivered from and through space. Militarily tensions seem to have been on the rise too. There are real concerns among the international rule-based nations about the challenging behaviours of Russia and China wreaking real havoc in space which even resulted in serious endangerment of the lives of American and Russian astronauts at the International Space Station. 

This article will shed some legal light on the recent announcement by US Vice-President Kamala Harris that the US would refrain from conducting destructive direct-ascent anti-satellite missile testing (i.e. destroying satellites in space). Whilst this seems to firmly place destructive actions at the centre of recent debates, the growing conduct of non-lethal operations such as jamming and spoofing should not be discarded. This article will therefore concentrate more widely on the international legal framework and military use of space. The main issue that will be addressed is whether the increased militarisation of space requires better norms and rules to ensure the responsible and peaceful use of outer space. There will be a brief reflection on the United Nations organisations that are leading efforts to bring nations together in the development of such norms and rules and where the international community is going next. 

Military Use of Space – the Relevant Law?

It seems inherently contradictory to talk about military and weapons in the same breath as outer space. In December 1963, the UN General Assembly unanimously adopted a resolution recognising the common interest of all mankind in the progress, exploration, and use of outer space for peaceful purposes. These words resembled similar aspirations as defined in the Antarctic Treaty a few years earlier. The main difference was that this Treaty also spelled out the prohibition of military activities whereas resolution 1962 did not. It has therefore been unavoidable that two interpretations of the term peaceful have emerged: one arguing a complete ban of all weapons in space, while the prevailing view does not represent such a prohibition. 

Let’s place the increased militarisation of space in the appropriate context by defining the international legal framework for outer space and reflect on the legal underpinning of military activities within outer space. The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, 1967, better known as the Outer Space Treaty (OST), and four other key treaties, commonly referred to as the outer space legal regime, together provide a legal foundation for ‘the expanding and increasingly complex tasks aimed at the exploration and use of outer space for peaceful purposes.’ In addition, the UN General Assembly has defined several principles as well as adopted various resolutions. Article I of the OST states that exploration and use of outer space, including the moon and other celestial bodies, is to be for the benefit of all mankind. Importantly, Article II clarifies that they shall not be subject to national appropriation and thus there can be no claims of sovereignty. The OST further states that the use of outer space, including the moon and other celestial bodies, shall be undertaken consistent with international law. This includes the UN Charter and is to conform with the UN’s purposes to maintain peace and security and the promotion of international co-operation. The deployment of arms in outer space is not forbidden nor is conflict in space specifically prohibited. However, the OST regime does include some restrictions limiting military activities and certain weapons.  The parties to the OST have agreed to not place any objects carrying nuclear weapons or any other kinds of weapons of mass destruction in orbits around the earth. Furthermore, it is forbidden to establish military bases, installations, and fortifications on the moon or other celestial bodies, as is the testing of weapons and the conducting of military manoeuvres.  

Most importantly, as the OST states that activities in outer space shall be conducted in accordance with international law and the UN Charter it is clear that they are also governed by existing principles of public international law that pertain to the use of military forces more generally. Therefore, tightly coupled to the UN Charter Article 2(4), with respect to outer space, any threat or use of force is prohibited. This is further amplified specifically for the moon prohibiting any other hostile act or threat of hostile act. It is similarly prohibited to use the moon to commit any such act or to engage in any such threat in relation to the earth, the moon, spacecraft, the personnel of spacecraft, or manmade space objects. In conformance to the UN Charter, and as per the laws of Jus ad Bellum, States may respond to an armed attack in self-defense provided that they meet the criteria of necessity and proportionality as argued in the Caroline correspondence. Furthermore, it is permitted to deploy force in outer space if so instructed by the UN Security Council (SC). However, there have thus far been no SC resolutions pertaining to action in space. Even so, as it is likely that such future actions may involve a response to the actions of one of the permanent members it should be anticipated that such action will be vetoed. Should States decide to breach the prohibition of the use of force, and armed conflict ensues in outer space, Jus in Bello or the Law of Armed Conflict (LOAC) applies. Similar targeting rules constraints apply in outer space thus limiting actions against military objects only or to the advancement of military objectives. More importantly, most destructive military actions are likely to damage outer space from a mere environmental perspective and render certain areas unusable for many decades and centuries to come. In conclusion, the increase in militarisation and military operations in outer space has resulted in a highly complex international legal framework. Some legal scholars such as Frans von der Donk and Fabio Tronchetti have argued that the international legal framework is lacking in coherence due to the distribution of applicable rules for military operations among various sources of law and the pre-eminence of the UN Charter versus the OST regime. Whilst state practice may be limited due to the low number of space-faring nations, many of the legal rules and principles are customary and, although potentially lacking in outer space specificity, they nevertheless bind states as well as inter-governmental and international commercial organisations. 

Preventing Bad Behaviour: Mitigating Risks of Damage and Threats of Escalation

It is often reported that debris in space is growing exponentially. The logical consequence of the increase in space activities is a growing risk of collisions with space objects, i.e. other satellites, and the creation and proliferation of new debris due to ever more launches. However, whilst some of this risk could arguably be mitigated through more cautious behaviour, there has also been a noticeable growth of capabilities to interfere with systems in outer space or even destroy them, and we have seen an upturn in deliberate malicious acts by actors seeking to affect the space activities of other nations. The most destructive forms are those of kinetic or physical counter-space weapons that directly hit satellites. 

In 2007 China used a missile to destroy one of its old weather satellites, resulting in thousands of sizeable pieces of debris. In 2019, India responded to this perceived Chinese threat by adding itself to the list of nations with anti-satellite capabilities when it successfully struck and destroyed one of its own small satellites, signalling to China India’s willingness and ability to protect its space assets. Last year Russia drew strong condemnation from across the international community when it decided to destroy one of its satellites, in the process posing risk of harm the astronauts then present at the International Space Station. 

Non-kinetic weapons can physically affect space systems without direct contact through the use of one or more of a range of technologies that include lasers, high-powered microwave, or electromagnetic pulses. Other harmful approaches may include signal transmissions to and from satellites and ground stations aimed at interfering with the radio frequency signals using techniques to disrupt signals (i.e. jamming) and falsifying signals (a.k.a. spoofing). Cyber attacks target the data rather than the radio signals. In the Gulf Region Iran has been known to have been jamming GPS signals creating false positions aboard ships in attempts to coerce them to move into Iranian territorial waters and justify intervention by their armed forces. 

A myriad of nations have electro-magnetic and cyber means capable of electronically disrupting assets and ever more capable technologies are still being developed. Russia and China have been successfully developing more advanced technologies such as orbiting robots and inspection satellites capable of rendezvous and proximity operations aimed at placing satellites in the plane and vicinity of other satellites. The arms race no longer seems to be a possible outcome but has rather become a worrying reality.

United Nations and National Leadership

The framework for state action in outer space is now far behind the technological possibilities, developments, and commercialisation of space. Nevertheless, the Proposed Prevention of an Arms Race in Space (PAROS) has been on the United Nations’ disarmament agenda for over four decades. Numerous nations have expressed their concerns about the harmful and damaging effects of this competition for space. While the discussions in the international community have intensified over the past decades these have not yet resulted in binding treaties or measures.

The UN Conference on Disarmament has been tasked with negotiating agreements for disarmament and weapons control but has not yet been able to achieve any new agreements pertaining to security in outer space and disagreements on how to achieve PAROS persist. In 2008, Russia submitted to the Conference a draft treaty on the prevention of the placement of weapons in outer space and of the threat or use of force against outer space objects. Various nations rejected the draft treaty out of hand stating that existing international law already covered most of the new treaty’s purposes and objecting to the omission of several existing capabilities. In 2014, Russia and China submitted a revised version of the draft treaty which failed to alleviate previous objections. The UN Disarmament Commission and the conference have only just ended a period of inactivity as a consequence of the Covid-19 pandemic and have not been able to achieve further progress.

In 2020, the General Assembly with 164 votes — 12 against and six abstentions — adopted a UK drafted resolution (GA Res 75/36)  for the reduction of space threats through norms, rules, and principles of responsible behaviours. In 2021, after extensive consultation, the UK successfully submitted another resolution (GA Res 76/231) proposing to establish an open-ended working group (OEWG) to consider threats and make recommendations on norms, rules, and principles. The OEWG will lead the efforts throughout 2022 and 2023. Because it is adopting a bottom-up approach based on identifying threats and challenges from nations’ own security perspective it is anticipated to be more successful than previous top-down object-based attempts.

The UN Office for Outer Space Affairs (UNOOSA) works to help all countries, especially developing countries, access and leverage the benefits of space to accelerate sustainable development through a variety of activities that cover all aspects related to space, from space law to space applications. It has established the Committee on the Peaceful Uses of Outer Space COPUOS) which is tasked with reviewing and fostering international cooperation in the peaceful uses of outer space, as well as to consider legal issues arising from the exploration of outer space. UNOOSA has also created several initiatives as platforms for young professionals to become involved and share knowledge and insight and has created internships; focused on building an outer space community fit for the future. 


This article has explored the international legal framework for outer space and military use of space. The increased militarisation of outer space and advancement of technological progress is increasingly resulting in threatening behaviours. Nevertheless, the international community, under leadership from the UN has been seeking to come to new agreements for disarmament in space, Regrettably, only little has been achieved thus far. Through the efforts of the UK, some success has been realised and the first steps have been taken in the development of better norms, rules, and principles to ensure the responsible and peaceful use of outer space. United Nations organisations will continue to play a leading role in the endeavour to bring nations together in this development. Transparency and the building of confidence remain high on the agenda and are paramount for any measure of success in this area at a time when the international legal order is being challenged to its core. When placed in this light, the US’ recent voluntary commitment is a great example, which will hopefully soon be followed by others.