from International Institutions and Global Governance Program

The Outer Space Treaty

Overcoming Space Security Governance Challenges

A satellite orbits Earth. NASA/iStock

Outer space is growing more crowded and contested. Rajeswari Pillai Rajagopalan recommends regulating activities that disrupt, deny, or destroy space systems to ensure outer space is available to all.

February 23, 2021

A satellite orbits Earth. NASA/iStock

This Global Governance Working Paper is a feature of the Council of Councils (CoC), an initiative of the Council on Foreign Relations. Targeting critical global problems where new, creative thinking is needed, the working papers identify new principles, rules, or institutional arrangements that can improve international cooperation by addressing long-standing or emerging global problems. The views and recommendations are the opinion of the author only. They do not necessarily represent a consensus of the CoC members, and they are not the positions of the supporting institutions. The Council on Foreign Relations takes no institutional positions on policy issues and has no affiliation with the U.S. government.

The Challenge

Rajeswari Pillai Rajagopalan

Distinguished Fellow, Observer Research Foundation

Outer space is crowded, with more than eighty countries either owning or operating satellites. The types of actors are also increasingly diversifying. Space is no longer only a realm of states. A growing number of nonstate actors, including the private sector and academic institutions, are also jostling for access. Simultaneously, outer space has become a more contested arena. Fueled by changes in regional and global balances of power, increasing security-driven competition in space has compelled many states to develop counter-space capabilities that can be used to disrupt, deny, or destroy space systems. These activities need to be regulated to ensure safe, secure, and sustainable use of outer space for all.

More on:


Global Governance

Diplomacy and International Institutions

International Law

Treaties and Agreements

These trends are proving to be a growing challenge for existing global governance mechanisms. Outer space activities are governed by a number of treaties and agreements, the foundation of which is the 1967 Outer Space Treaty (OST)—or, more formally, the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies. But these agreements were developed in the 1960s and 1970s, and they are showing their age. Constructed under different geopolitical and technological circumstances, they are not well-suited for addressing contemporary challenges.

The OST and four subsidiary legal instruments—including the Rescue Agreement of 1968, the Space Liability Convention of 1972, the Registration Convention of 1976, and the Moon Agreement of 1979—have, to a large extent, maintained the sanctity of outer space. But they also suffer from problems: they are open to expansive legal interpretations, which prevent them from restricting the weaponization of outer space. Unless more effective rules are developed to more comprehensively address counter-space technologies and activities such as on-orbit satellite servicing or rendezvous proximity operations, continued access to and management of outer space will face increasing difficulties, to the detriment of all countries. While new international legally binding measures are the ideal proposal, the current political and security environment will likely make them difficult to achieve. An alternative could be to focus on developing norms of behavior in outer space, but norms alone are unlikely to be sufficient.

This dilemma was evident at the most recent UN Group of Governmental Experts (UNGGE) on the Prevention of an Arms Race in Outer Space, which met in Geneva in 2018–19. The UNGGE’s inability to reach a consensus and produce an outcome report in its final session testifies to the enormous difficulties in space governance and the lack of consensus among the major powers on the definition of vital space security concepts, including what a space weapon is, what constitutes an armed attack in outer space, and the application of the right to self-defense.

Legally binding measures, including revising the OST, should be pursued in earnest, but the political impediments to developing new measures or amending existing measures are challenging to overcome. Given that the difficulties arise mostly from political disagreements, nonlegal, political instruments such as transparency and confidence-building measures (TCBMs) should also be pursued. While legal measures such as reforming the OST still need to be considered the end goal, this working paper recommends a step-by-step approach to addressing the political difficulties of developing effective rules of the road.

Two opposing perspectives prevail on global governance in outer space—one that believes that legal measures are necessary to resolve the problems facing the current space regime and another that argues that, given the contemporary political climate, traditional TCBMs are the more practical goal. A better approach could be something in between. This could take the form of a UNGGE developing legally binding TCBMs that encompass new outer space codes of conduct. While TCBMs are traditionally construed as political measures rather than treaties, legally binding TCBMs could be a useful middle ground.

More on:


Global Governance

Diplomacy and International Institutions

International Law

Treaties and Agreements


All major spacefaring nations should prioritize revitalizing the Conference on Disarmament (CD). The CD is the multilateral body in Geneva responsible for international arms control negotiations, including for outer space. But the CD has not participated in any significant negotiations for more than two decades largely due to member states’ disagreement on their annual program of work. If this stalemate continues to block new multilateral agreements, countries will be forced to rely on deterrence to protect their assets in outer space. This approach would be inherently destabilizing and would have a cascading effect: if one country relies on deterrence, others will be forced to follow, making further negotiations difficult.

Deterrence has not yet become the default policy for any state in outer space.

The world can still avoid this path. Deterrence has not yet become the default policy for any state in outer space. Before this happens, multilateral negotiations need to resume in the CD. Certain countries have a tendency to suggest other venues, but, to a large number of countries, the CD is the only multilateral institution that can negotiate a space security–related agreement. Many countries attach importance to the CD’s consensus rule for decision-making, which allows smaller, weaker members to veto decisions. On the flip side, this rule also holds agreements susceptible to the whims of any of the member states. Developing consensus among the major powers has remained the biggest stumbling block to creating an effective outer space regime, which means that the CD’s functioning will continue to suffer unless countries, particularly great powers, can sufficiently resolve their differences. Unless states find ways to revitalize the CD’s functioning and start agreeing on a program of work at the minimum, addressing the growing problems of governance in outer space will be difficult. Other venues such as the UN First Committee and the UN Disarmament Commission are too large and unwieldy to negotiate, while venues such as the UN Committee on the Peaceful Uses of Outer Space do not have the mandate to discuss military space issues.

All OST signatories should review and modernize the treaty. Although the OST has served as a useful instrument in ensuring safe and secure access to outer space, the development of counter-space capabilities including electronic and cyberwarfare measures is a major threat that needs to be dealt with. Counter-space capabilities are weapons that can destroy space-based objects or disrupt and interfere with space-based services through either kinetic physical attacks or electronic and cyber means. There are currently no effective regulations against them, as the OST only prohibits weapons of mass destruction (WMD) in outer space. Some states are now beginning to dangerously interpret the OST to mean that “non-WMD armaments in space do not violate international law.” Although customary international law could still be used to make the weaponization of outer space illegal, some states will likely exploit the OST loopholes.

Therefore, signatories need to review and modernize the OST in two ways. First, Article IV of the OST should be expanded to include conventional weapons and other non-WMD technologies, including land-based anti-satellite weapons and other counter-space systems. Second, the OST needs to refine ambiguous wording to provide greater clarity. Important terms in the OST such as “peaceful uses of outer space” have come to have such expansive interpretations that they are not useful in restricting irresponsible actions in outer space. For instance, some have interpreted “peaceful” to suggest the “nonmilitary” use of space, while others suggest it means “nonaggressive” behavior. Unless such basic concepts are clarified, the effectiveness of the OST, any other treaty, or TCBMs will be in doubt.

Formulating new rules of the road in outer space should be more inclusive. Although an inclusive approach to rulemaking is challenging, it critically leads to more buy-in from states, thus ensuring better compliance. Of course, developing an agreement involving all actors could lead to an instrument that is less than ideal because building consensus requires compromises, but ensuring more participation and endorsement is worth the effort. Processes and approaches are as important as the final outcome document. An inclusive process gives states a sense of ownership over drafting a treaty or a TCBM. The voice of emerging powers and developing countries is important in developing rule-based systems for global governance. An inclusive process that brings different stakeholders together should be pursued to ensure wider acceptability, which could lead to increased legitimacy and compliance. It will not help if this is done as an afterthought.

States should develop transparency and confidence-building measures.

The effort to create a Code of Conduct for Outer Space Activities in the European Union (EU) is illustrative in this respect. The substance of the EU code itself was not a problem. The code, for instance, recommended avoiding actions that create long-lasting space debris and called on states to undertake collision avoidance measures and participate in prelaunch and high-risk reentry notifications. Many countries outside the EU, such as China and India, opposed the code because they were not part of the development process. This prevented it from gaining broad support. To its credit, the EU eventually recognized the problem and reached out to other countries, but the damage was already done. This experience should be considered carefully, especially if efforts at the CD prove fruitless and geopolitical conditions do not improve. This kind of initiative of like-minded countries offers a path forward on space governance, but it needs to be done differently than the EU code. It would be useful to include a larger group of concerned countries at the start of the deliberative process.

States should develop TCBMs. Reviewing and modernizing the OST will take time. Developing TCBMs could bridge the gap as an intermediate step to legal instruments, which should remain the ultimate goal. TCBMs should be seen as useful, pragmatic steps in building trust among countries. They can strengthen dialogue among multiple stakeholders and encourage openness, information sharing, and transparency. TCBMs have the flexibility to start with the least common denominator, measures that all parties agree to. These could include norms of responsible behavior, an outer space code of conduct, or GGE activity. Despite the failure of the most recent UNGGE on the Prevention of an Arms Race in Outer Space, such efforts still need to be pursued. TCBMs can be narrowly focused and start with specific measures, such as “no testing/deployment of space weapons in outer space,” before proceeding to broader issues, such as “noninterference with peaceful activities of other states.” Adopting specific TCBMs such as prelaunch notifications can also strengthen efforts to establish norms of responsible behavior and regulate activities and capabilities that are inherently destabilizing.

A recent proposal from the United Kingdom (UK) on space security can be a helpful reference. The proposal, “Reducing Space Threats Through Norms, Rules and Principles of Responsible Behaviors,” aims to look at space security challenges with a bottom-up approach. One of the operative clauses in the proposal asks countries to “characterize actions and activities that could be considered responsible, irresponsible or threatening” and share their ideas on how they can be managed. That the UK proposal focuses on a behavior-based approach and does not favor a specific format for its outcome leaves reasonable flexibility for states to discuss and arrive at an advantageous outcome.

States should pursue innovative multilateralism. Given the challenges surrounding the CD, states should consider setting up a body akin to the Intergovernmental Panel on Climate Change to address some of the pressing challenges in outer space. Similar to the GGE, the group could be established through a UN General Assembly resolution, but for a period of two or three years. Such a group of international experts could be mandated to review universal challenges confronting every state, including space debris, the outer space arms race, and counter-space capabilities, and produce an outcome document that can be submitted to the UN secretary-general. The group could be an inclusive platform with policy and technical experts from developing and developed countries, thus providing a voice to emerging powers. States could also consider creating an institution modeled after the International Civil Aviation Organization, given the importance of space traffic management in handling outer space affairs. Having a group of technical experts ideating possible resolutions could alleviate some of the political issues that have prevented consensus among major powers. States could also pursue smaller, technical agreements addressing a particular threat rather than attempt all-encompassing treaties, which are difficult to build support for.

The United States has taken the lead in lunar exploration.

The United States’ Artemis Accords are an innovative attempt at forging international cooperation, but the bilateral approach has limits. The United States has taken the lead in lunar exploration through a series of bilateral agreements, reinforcing many of the norms and principles enshrined in the OST. Although countries including Australia, Canada, Japan, the United Arab Emirates, and the United Kingdom have signed on, space powers such as China, India, and Russia have not. Geopolitical rivalry with the United States will likely prevent China from accepting these arrangements, and India and others have avoided signing on because it is not a multilateral agreement under the UN umbrella. A better approach to promoting OST norms in lunar exploration would be developed under the aegis of a multilateral entity.


Although the outdated regime is a stumbling block, the bigger challenge to outer space governance is the lack of consensus among major spacefaring powers. Failure to develop consensus on everything from what the major challenges are to what possible resolutions can be found is of particular concern. Although technical, legal, and political challenges are involved in the development of global rules of the road, the political obstacles are most important. Unless sufficient political attention is paid to the issue, states are unlikely to find a way to bridge their differences, and work on both legal measures and TCBMs will suffer. All countries ought to consider what sort of future space is desirable, what behavior is counterproductive, and accordingly what norms should be pursued in their own enlightened self-interest. The alternative is that countries will no longer be able to consider outer space a global commons—a scenario in which everybody loses.

This paper benefited from numerous comments and suggestions from Council of Councils members, in particular Stewart Patrick (Council on Foreign Relations) and Juan Battaleme (Argentine Council for International Relations).

Top Stories on CFR


The closely watched elections on July 28 will determine whether incumbent President Nicolás Maduro wins a third term or allows a democratic transition.

International Law

The high court’s decision could allow future U.S. presidents to commit grave abuses of power with impunity, with serious implications for U.S. foreign policy and national security.

Election 2024

The Ohio senator is Donald Trump’s choice as his running mate for the 2024 presidential election.