The emergence of outer space as an increasingly important domain of international activity raises fundamental questions for International Relations. The relationship between sovereignty, strategic competition, international institutions, and cooperation becomes particularly complex when political activity extends beyond the traditional territorial boundaries of states.

The historical foundations of international politics provide an important starting point for understanding these questions. The Westphalian idea of sovereignty, the Space Race, and the development of international institutions demonstrate how states have sought to protect their interests while simultaneously creating rules for competition and cooperation.

This raises a fundamental question: Do the traditional theories of International Relations still explain politics beyond Earth?

Realism, Liberalism, and Constructivism offer different perspectives through which space governance can be examined. These approaches can help explain why states cooperate in projects such as the International Space Station while simultaneously competing over strategic capabilities, influence, and the future use of space resources.

Realism reminds us that states pursue their interests, while neorealism places particular emphasis on international anarchy, uncertainty, and the distribution of capabilities. This leads to a difficult question: If no higher authority can ultimately compel a great power, why would a great power voluntarily accept meaningful constraints on its freedom of action?

Outer space makes this question particularly interesting. International institutions, legal rules, the “province of all mankind” principle, shared infrastructure such as the ISS, and cooperation between states that may also be strategic competitors all exist within an international system that remains fundamentally decentralized.

This raises several questions. Can cooperation be sustained when trust is limited? Can a system remain anarchic without necessarily becoming chaotic? Can institutions meaningfully constrain state behaviour without eliminating anarchy? And perhaps most importantly, can great powers accept constraints that they do not strictly need to accept?

These questions do not necessarily demonstrate that realism or neorealism is inadequate. Rather, they raise the possibility that these theories may face difficult questions when applied to the space domain.

The increasing strategic importance of outer space also raises questions about international norms and the role of emerging and developing states. Power in international politics is not distributed equally. Emerging states may not possess the same economic, military, or technological capabilities as great powers, but this does not necessarily mean that they cannot influence the development of international norms and institutions.

This brings us to another question: Can the Westphalian understanding of sovereignty be applied to the political environment of outer space?

On Earth, sovereignty is strongly connected to territory. Outer space is different. States cannot simply claim the Moon or other parts of space as their territory. The political and legal environment of outer space therefore requires different mechanisms for managing competition, cooperation, and strategic interests.

The Artemis Accords provide an interesting framework through which these questions can be examined. Transparency, information sharing, coordination, and peaceful activities can support cooperation and reduce the possibility of misunderstandings. However, trust is not created simply by signing an agreement.

How can trust be built between states with different strategic interests? What should states do when cooperation and national interests begin to conflict? And perhaps the larger question is whether anarchy and the balance of power should be understood as permanent characteristics of international relations, or whether long-term peace in outer space is possible.

The goal may not be to eliminate competition completely. Perhaps the more realistic question is whether rules can be created to limit how states compete.

This also leads to another possibility: Can rivalry produce restraint instead of escalation?

Great powers do not always want to limit their power. They protect their interests, seek security, and often distrust their rivals. This is one of the central problems associated with realism and the security dilemma.

Yet rivalry does not necessarily have to produce escalation.

Space provides an interesting example. The United States and Russia have remained strategic rivals while cooperating in areas such as the International Space Station. This suggests that cooperation does not always require complete trust. Shared interests and mutual dependence can create limited forms of cooperation even between rivals.

The 1967 Outer Space Treaty also presents outer space as the “province of all mankind.” Yet legal equality does not mean equal capabilities. Great powers continue to possess very different technological, economic, and strategic resources.

International institutions can create rules and legitimacy, but they cannot automatically control great powers.

Perhaps, therefore, the goal should not be to eliminate rivalry. Instead, it may be useful to examine whether rivalry itself can create incentives for information, predictability, and restraint.

Information → Predictability → Restraint

If rivals already have strong reasons to monitor each other, could this competition be structured in a way that reduces uncertainty and creates opportunities for restraint?

This does not provide a final answer. It presents a possibility: perhaps the challenge is not to end rivalry, but to structure it.

Could rivals become each other’s monitors—and could that make peace more sustainable?

These questions are central to the study of Space Diplomacy and to the broader relationship between international cooperation, space governance, and the peaceful use of outer space. They also demonstrate why the space domain may require International Relations scholars to reconsider some of the assumptions traditionally associated with sovereignty, anarchy, power, cooperation, and strategic competition.

The objective is not to present a finished theory.

It is to test an idea.

Perhaps this is where research begins: not with having the final answer, but with asking a question that is difficult enough to keep exploring.