1 Introduction¹

Diplomacy matters to outcomes in international relations, and space is another realm in which it occurs.² At no time has it been more necessary to take up the challenge of better understanding diplomacy’s scope and limits than in the unfolding realities of what some are calling a new space race.³ On the one hand, these realities promise prosperity and progress for humanity as never before. The global space economy is now estimated to be nearly USD450 billion in size and is projected to grow to over USD1 trillion by the 2040s.⁴ Reusable rocketry, mega-constellations, off-world habitats, service spacecraft and autonomous robotics, among others, are technologies that hold promise for the exploration of space and for tackling the economic and digital divides around us. On the other hand, the dual-use nature of some of these same space technologies calls peaceful prospects in outer space into serious question.⁵ These dangers are amplified in a world that has seemingly returned to great power competition, in which national rivalries are extending to outer space.

In this special issue, we take up the challenge of assessing the prospects for space diplomacy, which we define as processes of dialogue, carried out by actors in pre-existing or emerging contexts, structures, institutions or venues, which result in outcomes of co-operation or conflict on a given space issue. In doing so, these actors use formal and informal mechanisms (i.e. ‘what happens between a cause and its effect’⁶) to communicate norms, persuade others of the merits of their thinking, or bargain in the spirit of achieving a successful compromise.

In the remainder of this framing article we bring together the fields of international relations and space studies to advance our understanding of space diplomacy in the scientific, economic and military realms. To the best of our knowledge, this special issue is the first in the field of international relations to use theories of diplomacy to bring to light the various ways in which experts, scientists, astronauts, space enthusiasts and professional diplomats, among others, have shaped the formal and informal interactions among states when it comes to this key area of foreign policy.

This introductory article proceeds as follows. We first identify and situate many aspects of space diplomacy in the broader international relations (IR) literature, emphasising the importance of processes among state and non-state actors in many of the field’s mainstream paradigms. Second, we lay out a framework of analysis that captures the main mechanisms by which space diplomacy occurs, namely persuasion, communication and bargaining. Finally, we provide an overview of the articles and practitioners’ perspectives that comprise this special issue, and what they ultimately say as a whole in terms of explaining the outcomes of space diplomacy. Embracing an analytically eclectic approach, we leave it to each empirical contribution to advance a causal argument about the mechanisms that underpin their case studies of space diplomacy.

2 The Varieties of Space Diplomacy in International Relations

In the mainstream IR literature, the notion that processes of diplomacy matter is not a given.⁷ Many IR scholars argue that diplomatic processes only serve to minimise transaction costs of negotiations among states or to find optimal bargaining outcomes based on the self-interest of the actors involved.⁸ Others argue that processes of diplomacy do not matter at all because outcomes of international relations simply reflect the relative power and interests of dominant states.⁹ By contrast, in this special issue, we argue that diplomacy can have an independent impact on international outcomes because these processes can result in more than the sum of their parts. For example, the existence of the International Space Station (ISS) cannot be explained simply by looking at relative power or hard bargaining; it is also the product of historical setbacks and the slow-moving realisation of international collaboration on human presence in space.¹⁰ Nor can the legal framework of space security be explained without the concerted, nationally minded efforts of both the United States and the Soviet Union to create it through treaties and agreements. As then so now, space diplomacy will continue in ‘fits and starts to address commonly identified problems’.¹¹ The diplomatic studies literature recognises that processes of persuasion, deliberation, compromise and consensus impact outcomes in fundamental ways. The more important question is under what conditions they are likely to be successful or not.

Historically, space has been regarded as both central to Cold War military competition and an arena in which co-operation was highly desirable despite this competition.¹² Today, space has a bearing on economic, scientific, cultural, political, climate and industrial interests, and it involves many different types of actors and processes. Daniel Deudney, for example, argues that space expansionism presents deep and possibly catastrophic risks but, if moderated, could bring societies together around an ‘Earth-centered pro-space agenda’ focused on nuclear security and the protection of the environment, instead of military conquest and colonisation of space.¹³ Along these lines, the October 2022 Biden-Harris US National Security Strategy stipulates that when it comes to space, the US will ‘lead in updating outer space governance, establishing a space traffic coordination system and charting a path for future space norms and arms control’.¹⁴

The emphasis on law, norms and governance has been a subject of long-standing interest to lawyers, legal analysts and practitioners.¹⁵ In comparison to the scholarship on space law and policy, it is fair to say that space studies still has inroads to make in the field of IR and has largely remained a niche topic for IR specialists interested in space security and politics. So far, much of the space-related IR research has focused on conflict, competition and co-operation, but with little reference to the role of diplomacy more explicitly as a process among actors.¹⁶ Together, though, these works give us foundational building blocks for thinking about how and whether states can diplomatically forge policies in an international context riven by great power competition. Some question the premise of diplomacy in the space domain. As Paul Meyer notes, it is true that diplomacy has been steadily downplayed by states; but even though it is the ‘missing ingredient from current considerations of space security [it may nevertheless help to] realign the depiction of outer space as a realm of promising international cooperation rather than one of inevitable confrontation and conflict’.¹⁷

In the space domain, the three mechanisms of diplomatic processes on which we focus in this special issue — that is, communication, persuasion and bargaining — involve shifting constellations of both state and non-state actors, who may be motivated variously by visions of profits, security, exploration, science and development. Among them are professional diplomats, space agencies, private companies, start-ups, think tanks and even individuals, such as so-called space billionaires. The foundations and flows of space diplomacy rest and are also spurred on by these actors’ scientific knowledge, industrial innovations, technical expertise and sheer experience that traverse the public and private spheres in this new era of space exploration. As they interact across borders in many types of fora, these actors and elements also criss-cross, infuse and shape the prospects for many varieties of space diplomacy, as will be discussed. In doing so they also showcase linkages to the theory and practice of international relations — that is, to some degree they all have a bearing on politics — which we highlight as we move along.

The most obvious manifestation of diplomacy in outer space activities is through what scholars identify as science space diplomacy, a distinct category that is defined as diplomatic processes leading to international scientific, including technological, co-operation or competition.¹⁸ A 2010 Royal Society report further delineates science diplomacy as occurring in three forms: diplomacy for science (state actors co-ordinate to facilitate scientific endeavours), science in diplomacy (states use scientists to inform foreign policy choices in war or peace) and science for diplomacy (scientists facilitate relationship-building among states).¹⁹ In all three areas, science can be an area in which co-operation is possible even in the context of tense political relationships. As the report states, ‘science provides a nonideological environment for the participation and free exchange of ideas between people, regardless of cultural, national or religious backgrounds’.²⁰ The soft power of science can enrich traditional diplomacy, public diplomacy and cultural diplomacy even at the most difficult times.²¹ Here Joseph Nye’s concept of soft power is useful in understanding the nature of space capabilities as a form of attractive power. Nye includes cultural products, ideology and institutions of a nation as comprising soft power resources.²² Soft power is defined as attractive power, as opposed to its counterpart hard power, which is coercive.

Science diplomacy is not just about using scientific and technological capabilities to enhance the image or attractiveness of a country (often associated with public diplomacy); it is also about a process of engagement and dialogue between actors, scientists and states which, when successful, can result in co-operation. One argument is that science diplomacy matters when there is a clear need for a certain type of expertise.²³ Scientific knowledge has long been in demand in this respect. Science diplomacy has been conducted both by professional diplomats concerned with scientific issues, and by scientists engaged in professional diplomacy.²⁴ There are numerous examples of professional diplomats deliberating over issues grounded in science, and they often seek the advice of scientists in the background. But at other times, scientists engage in diplomacy directly, and even formally. For example, environmental scientists supplanted the role of diplomats in helping the United States, Canada and Mexico agree to migratory bird treaties in the early 20th century.²⁵ Countries also use science diplomacy to maintain people-to-people connections in the context of political turmoil. For example, the United States engages with Iran through science, with programmes such as the Jefferson Science Fellowship and scientific collaborations through the American Association for the Advancement of Science, National Academy of Science and National Institutes of Health, among others.²⁶ The United States also maintains the Science Envoy Program as part of its science diplomacy effort more generally. Science diplomacy has actually been around for centuries, even if it has not always been recognised as such.

While in many respects space is a clear example of science diplomacy, it also extends beyond this since space has many implications that are not simply about scientific pursuits. Space has a clear bearing on economic, commercial and military interests. In this context, even science itself may become ‘instrumentalised by foreign policy’.²⁷ Scientific advancements in space make strong contributions to soft power and the idea that we as humans have more in common than issues that divide us,²⁸ but they also raise issues of technological innovation and commerce that underwrite the wealth of nations. Further, science diplomacy, contrary to being always co-operative in goals, can actually have both a ‘statist approach’ and a ‘globalist approach’ — analytics which help to link space activities to IR frameworks more generally. Pierre-Bruno Ruffini argues that science diplomacy can be statist in that it is ‘a subset of the country’s foreign policy … advancing broader foreign policy goals’, or it can be globalist in that is ‘critical to inform policy for addressing global challenges … engagement in the international system and in collective action’.²⁹

This clearly resonates with space diplomacy more generally in that policies and outcomes often demonstrate a strong desire to tackle common challenges — for example, building a new space station, creating a permanent presence on the Moon, taking humans to Mars, discovering medical breakthroughs, dealing with space debris and so on — while at other times seeming to instead reflect concerns of national interest — such as building the capacity to protect and destroy satellites, launching more powerful rockets, guarding space intelligence and so on.

Thus, another important variety of space diplomacy can be thought of as economic space diplomacy, especially as states all around the world are becoming ever more invested in capitalising on the industrial and technological benefits derived from space. Given the forecasts of growth as noted at the outset, these trends have the momentum to build more peaceful relations among states — echoing long-standing IR works on economic interdependence as a force for peace. Advocates of the commercial space peace, who are mindful of the challenges in contemporary geopolitics, argue nonetheless that the ‘chance of conflict in space is less than commonly understood or recognised precisely because of the extent to which the global economy has become dependent on space-based assets’.³⁰ With the assumption of rational states, the basic contention is that, as the economic costs of conflict rise, power-seeking countries will be dissuaded from weaponisation and all manners of disruption. Economic space diplomacy, for example, could focus instead on negotiating new contracts for national space industries or building consensus on state practice through national legislation. These realities may build mechanisms for restraint and possibly diplomatic rapprochement between states, aided also by the rising stakes of private companies. Whether this happens through formal or informal fora, it raises the analytical possibility of communication, persuasion and bargaining playing a key role in governing a mutually beneficial and peaceful space economy.

Of course, we are mindful that not all states are equally dependent on space assets for their economic well-being, and this may create different incentives and unexpected outcomes in space diplomacy. And, as diplomatic interactions increase, there is of course the question of whether there is a fundamental difference in the kind of diplomacy that addresses space-centred goals versus Earth-bound goals. Further, not all observers see such positive prospects in this new space age, instead pointing to the higher likelihood of cut-throat competition to see who can reap the biggest rewards from being at the frontiers of space exploration.³¹ But a focus on economic space diplomacy offers a corrective to the caricature of space as a battleground, both historically and today. There is a danger in self-fulfilling prophecies, and over the past 70 years, we can actually observe an under-recognised but growing arena of diplomatic activity surrounding space. From the early years, even before spaceflight was possible, there was a transnational spaceflight movement that conceived of the future of space as fundamentally peaceful.³²

To be sure, space diplomacy is often possible because it rests on the political neutrality of knowledge and expertise in space,³³ and the desire to achieve international economic co-operation; but if efforts at diplomacy fail, space may quickly come to be seen as an arena of conflict and competition for dominance.³⁴ From a realist perspective, Everett Dolman forecasts that this breakdown is actually likely and proposes a so-called Astropolitik (building on realpolitik) roadmap for the US to prevail in great power competition in space.³⁵ While this pessimism may or may not be warranted, it does help to link to prospects for a final variety of space diplomacy, specifically military space diplomacy. This is rising in salience as the world returns to great power competition and it heats up particularly between the United States and China. It is also fuelled by the dual-use nature of space technology, which means that space assets can be transposed form commercial to military purposes. The paradigm of realism, along with the study of war, conflict, power and strategy, seems to strike many as being inhospitable to diplomatic processes.

But diplomacy has long played a role within them, dating back to Thucydides’ work on the Peloponnesian War in which some of the most memorable passages are those where envoys, leaders and ambassadors spent much time trying to communicate and persuade their audiences about the merits of their positions.³⁶ Diplomacy plays a prominent role for many realist theorists and practitioners.³⁷ Hans Morgenthau once wrote: ‘Of all the factors that make for the power of a nation, the most important, however unstable is the quality of diplomacy … Diplomacy, one might say, is the brains of national power … .’³⁸ It is diplomatic history that forms the evidence for one of the most celebrated books on why states come together or not as allies.³⁹ Using a state-centric neoclassical realist framework, one work is making inroads into understanding the prospects for counterspace technologies, organisational changes and space diplomacy more explicitly.⁴⁰ Going back to Morgenthau, there is a striking similarity and one strong difference with the three mechanisms of interest in this special issue. He writes that there are three means at the disposal of diplomacy, namely ‘persuasion, compromise, and threat of force … [and that the diplomat from a great power] in order to serve both the interests of his country, and the interests of peace, must at the same time use persuasion, hold out the advantages of compromise, and impress the other side with the military strength of his country’.⁴¹

3 A Framework of Analysis for Space Diplomacy

Our objective in this special issue is to advance both theoretical and empirical knowledge about when, why and how space diplomacy manifests in practice, and more broadly, to what extent, in what areas and why collaboration is possible. At the broadest level, we seek to identify the nature of specific diplomatic mechanisms that lead to co-operation in space and use IR frameworks to explain why they succeed or fail. This is important for both theory and practice in the present geopolitical flux. As space becomes more accessible, the potential for actual conflict — going beyond competition — presents itself. Thus, with the help of our contributors, we seek to illuminate the extent to which the three mechanisms of space diplomacy promote peaceful interaction across borders versus conflict and militarism. The literature on space diplomacy has been relatively silent on the mechanisms behind its effectiveness, and thus our framework of analysis seeks to address this gap by incorporating insights from diplomatic studies more generally.

As a general framework for our contributors, we identify mechanisms that are informed by the nature and motivations of the actors in specific space-related issue areas. By mechanisms, as will be discussed, we identify (1) communication, (2) persuasion and (3) bargaining as crucially important. By setting them up as distinct mechanisms, we are not suggesting that they are moving in a linear or clockwork fashion towards some teleological endpoint of co-operation. Rather, we are distinguishing them because, analytically and practically, they are likely to be marked by different degrees of deliberate, strategic and goal-driven behaviour by the actors involved, and they may be used in combination with one another. Nor are we suggesting that these are the only mechanisms of import, as previously noted especially in the case of military space diplomacy, but by and large they chime well across most works. Finally, it is worth mentioning that those engaged in space as actors are broad-ranging and diverse and cannot be presumed to have similar interests or preferences to their counterparts on any given issue across countries or even within their home country, including states (i.e. heads of states or professional diplomats), epistemic communities, scientists and engineers, lawyers, academics, companies, entrepreneurs and private individuals (e.g. space billionaires, activists, citizens).

Through focusing on some combination of communication, persuasion and bargaining, we ask our contributors to elucidate — or not — the processes laid out in each.

1. Communication (framing, narratives, norms communicated to the public or transnationally)

   1. Any space actor may engage in national, transnational or international communication about the importance of space. This can be in the form of formal or informal public diplomacy, including cultural, scientific or technological outreach, among others, leading to the perception that space is a realm of collaboration.

   2. Engagements in scientific networks or epistemic communities/coalitions may involve continual mutual communication of scientific findings and reiteration of shared goals in space.

The diplomatic studies literature offers valuable insight into the role of communication as a mechanism for successful interaction among diplomatic actors. The process of diplomatic communication can involve conveying information through public relations or outreach initiatives, such as explaining the value of investing in space to the regular public. Perhaps more importantly though, communication can involve mutual engagement between publics and diplomatic actors or within groups, such as epistemic communities. Mutual engagement with the public often happens in the form of public diplomacy, which includes cultural and scientific diplomacy and is broadly defined as ‘the communication of narratives that embody key norms about a society’.⁴² In the context of space diplomacy, these narratives are about the human presence in space itself, for example, the history, inspiration, meaning, value, identity and progress behind human aspirations in space.

By contrast, private or internal communication occurs within groups of space diplomats. It is often practice-oriented, such as verbal or non-verbal signalling or rituals such as diplomatic protocol.⁴³ State and non-state diplomatic actors alike benefit from frequent informal interactions, ‘everyday social practices’ and socialisation to promote trust and, ultimately, consensus.⁴⁴ Private communication is also substantive in that it is an opportunity to continually reiterate shared goals in and knowledge of space, from science to investment to exploration. The various ways in which communication serves as a mechanism for diplomatic processes demonstrate how space diplomacy can facilitate broader international co-operation.

2. Persuasion (deliberation between space diplomats and political actors)

   1. Spillover/trust: Success in initial scientific sharing⁴⁵ (facilitated in part by common technical language,⁴⁶ shared scientific method and open-source data in addition to diplomatic processes)⁴⁷ influences the political level, which then enables more space co-operation and to some degree insulates space co-operation from geopolitical conflict.⁴⁸

   2. Arguing: Scientists, diplomats or other non-state actors convince states and each other of the value of co-operating through framing, narratives, expertise, epistemic communities, informal interactions, socialisation and normative influence.⁴⁹

Persuasion is another type of mechanism underpinning effective diplomacy, and in the diplomatic studies literature, it traces much of its origins to Jürgen Habermas. It occurs both within groups of space diplomats and between space diplomats and political decision-makers. Persuasion goes beyond communication in that it is a form of arguing with the aim of changing the minds of others to find new areas of consensus that benefit the common good.⁵⁰ As Pauline Kerr notes, however, a change in mind is not always possible, but persuasion could still result in a compromise outcome.⁵¹ The act of persuasion is facilitated by prior relationships, trust, shared language, face-to-face interactions, the ability to convey resolve and open-mindedness, among others.⁵² On one end of the spectrum, ongoing diplomatic interactions built on trust make persuasion straightforward, while on the other end, persuasion may sometimes involve some level of coercion stemming from the broader political context (i.e. political or economic concerns of states in a given issue area).⁵³

To identify persuasion as a mechanism of space diplomacy, one must look at the nature of deliberation between and among state and non-state space actors. Do they use evidence, causal beliefs and validity claims to make ‘good’ arguments about co-operation in space? Do they draw upon prior understandings, scientific co-operation and shared norms about the role of space for humankind to seek a common starting point? Does persuasion occur in both formal and informal settings, and face to face? Do diplomatic actors invoke the common good, that is, the benefit of co-operation in approaching investments in space?

2. Bargaining (state actors strike deals based on self-interest)

   1. Strategic negotiations result in tit-for-tat trade-offs among space diplomats (state or non-state) who seek to maximise their state’s self-interest through bargaining with other states.

Finally, bargaining is distinct from communication and persuasion in that it is far more strategically focused on individual or national self-interest. The mechanism for finding agreement through diplomacy is tit-for-tat exchange. As articulated in Robert Putnam’s analogy of a two-level game,⁵⁴ Andrew Moravcsik defines diplomatic bargaining as a ‘process of strategic interaction in which actors simultaneously try to take account of and, if possible, influence the expected reactions of other actors, both at home and abroad’.⁵⁵ He argues that this often results in lowest common denominator agreements.⁵⁶ The diplomatic studies literature has delineated many forms in which bargaining takes place, such as logrolling, normative entrapment, co-operative bargaining and competitive bargaining, among others.⁵⁷ Although it is generally rationalist in strategy, tit-for-tat exchange can also happen over what constitutes shared norms, identity and the ‘logic of appropriateness’.⁵⁸ In this sense, when it comes to space diplomacy, bargaining can occur within the context of co-operation in space, such as the set-up of the ISS or the Artemis Accords. Considering the underlying power and materialist dynamics involved in bargaining, more often than not it involves state actors.

It is important to note that these three types of mechanisms represent a spectrum of approaches to space diplomacy — from more ideational to more self-interested — that connect to larger debates on outcomes in space (i.e., militarisation, exploration, new laws, environmental concerns and so on). They also allow us to shed light on how actual processes of space diplomacy matter. As our contributors discuss in depth, many events may trigger or change ongoing processes of diplomacy in the realm of space. For example, the explosion of a satellite, mining of asteroids, problems of space debris, return to the Moon and exploration of Mars, among many other issues, could lead to space diplomacy processes that invoke one or more of these mechanisms and play an important role in determining whether outcomes are co-operative or not.

Just as these mechanisms often facilitate successful diplomacy, in the realm of space, they may also derail efforts if they are relatively weak. Communication could, for example, feature conflictual rhetoric that amplifies the language of dominance or the notion of a space race, potentially leading to a sense that conflict is inevitable. Persuasion could backfire if there is a lack of trust or common language. And bargaining could lead to ultimatums that back states into a corner. Through a close examination of these processes, however, we contend that if at least one of these mechanisms is strong, outcomes are likely to be more co-operative, and we draw out the specific ways in which space is also a unique venue for diplomacy.

Each contributor to the special issue investigates the role these actors play in affecting or influencing outcomes in space diplomacy. Each mechanism has an important bearing on how states and non-state actors engage in space diplomacy, and the outcomes that emerge. Delving more deeply into one or more of these mechanisms, each author puts forward theories specific to his or her case study. If at least one of these mechanisms is strong, we claim that continued or new areas of co-operation in space are more likely. If they are weak or break down, then co-operative outcomes become more difficult. For example, if tensions on Earth push states to view space as a place of great power competition, despite other motivations and efforts, space diplomacy may fail.

Within this general framework we also ask our contributors to address some overarching questions that help to glue the volume together and that draw on IR frameworks to advance our understanding of the analytics driving the three mechanisms. First, when, why and to what extent have states or non-state actors strived to co-operate when it comes to space? For example, is it mainly about cost sharing, the need for outside scientific knowledge,⁵⁹ shared norms, space security or other factors? Second, what are the major difficulties in reaching successful compromise involving space diplomacy, and why? Third, why do some efforts at space diplomacy succeed while others fail? These questions are particularly important in the context of today’s emerging international relationships when it comes to space and the different perspectives on what this means for the future.

4 Overview of the Contributions in this Issue

All the contributors to this special issue agree that processes of diplomacy matter to international co-operation in outer space. Through a broad-ranging and in-depth examination across key cases, all contributors find that communication and persuasion are ubiquitous as key mechanisms behind these diplomatic processes. Thus, to a lesser extent, bargaining is present alongside communication and persuasion, but it is not as common.

William Stewart and Jason Dittmer take a historical perspective on science space diplomacy through examining the role of materiality in space diplomacy, and specifically the example of orbital docking technology.⁶⁰ Drawing on the use of assemblage theory in political geography, their article argues for a ‘more-than-human’ approach to space diplomacy to supplement and provide an alternative to conventional approaches to diplomacy studies. By focusing on the ways communication and persuasion in space diplomacy fostered closer relations between the United States and Russia, specifically around material co-operation on androgynous orbital docking technology, they show how collaboration and peace in the space domain emerged in the wake of the Cold War and continues today.

Examining more present-day challenges to maintaining a permanent human presence in space, Kunhan Li and Maximilian Mayer compare two central pillars of China’s crewed space programme.⁶¹ They observe that Chinese space diplomacy is not uniform regarding international scientific co-operation in both its approaches. In the case of the Chinese Space Station programme, the China National Space Administration went through the existing United Nations channels and successfully attracted international partners. However, the International Lunar Research Station has avoided UN channels and used national and bilateral platforms. In contrast to the US Artemis Program, the bilateral co-operation is limited to Russia and it has failed to attract other major partners at this stage. This bifurcation in approaches and results offers an intriguing puzzle concerning international co-operation: practices of institutionalised multilateral co-operation and areas of state-centric bilateral co-operation co-exist in this case and further complicate the issue of space diplomacy. To propose a potential explanation, Li and Mayer argue that a crucial intermediate variable — institutional density — requires further theorising, as it seems to influence strategic choices about space diplomacy, which may lead towards success or failure. China’s bifurcated strategy also highlights the ways in which institutional density varies across different areas of (outer) space. This variable needs to be further conceptualised as a factor that enables science, economic and military space diplomacy, or that makes it harder to realise.

Saadia M. Pekkanen probes Japan’s space diplomacy in a world returned to great power competition.⁶² She argues for paying closer attention to the wide variety of governing contexts through which purposeful states such as Japan channel their overlapping science, economic and military space diplomacy. Governing contexts that are characterised by hard law and formal organisational structures (such as those under the auspices of the United Nations) are as important to the mechanisms of communication, persuasion and bargaining as are those marked by soft law and informal interactions (such as regional intergovernmental institutions and persistent interactive dialogues).⁶³ A holistic approach also helps to capture the full gamut of Japan’s space diplomacy at the global, regional and bilateral levels. Her principal argument is that Japan’s space diplomacy is carefully designed to serve the country’s national interests, reflecting a criss-crossing blend of science, economic and security concerns. In line with the country’s changing security realities, she asserts that Japan’s space diplomacy is predicated on the country’s advanced space technologies and can be summed up as proactive positioning. Japan’s space diplomacy cultivates an image of a pacifist and responsible actor in the international order and helps set expectations about building consensus on peaceful prospects in outer space.

On the other end of the political and normative spectrum, Marianne Riddervold examines the role of the European Union (EU) in space diplomacy.⁶⁴ The EU has become one of the key players in space, second only to the United States. She analyses what type of diplomatic actor the EU is in space by exploring whether the EU contributes to peaceful co-operation in space or if the EU — influenced by more conflicts on Earth — is developing into a more strategic, realist power. For this purpose, her article combines our space diplomacy framework with Riddervold and Newsome’s framework for exploring actors’ co-operation, conflict and interaction in the global commons,⁶⁵ empirically focusing on how the EU communicates its policies and how it seeks to persuade others to follow its approach. This framework proved helpful for teasing out the EU’s diplomatic practices in space. She finds that the EU contributes to peaceful diplomatic practices in space through the mechanisms of bargaining and communication. Although not primarily driven by the space flight idea, the EU is committed to the peaceful development of space for economic, strategic and societal purposes. Even when moving to space, multilateralism and co-operation are in the EU’s DNA.

In her article, Nikita Chiu, seeks to contribute to the burgeoning scholarship on military space diplomacy by investigating the interplay and dynamics of two major issue-domains: disarmament and outer space.⁶⁶ She analyses three significant cases since the Cold War, when space technologies constituted a significant topic in diplomatic exchanges and in advancing foreign policy objectives related to global arms control, disarmament and non-proliferation. She contends that space diplomacy reflects a process that often involves actors beyond the state. Inputs from scientists, weapons inspectors and photo interpreters, whose roles were sometimes thought to be functional, often have direct or indirect impacts on actions, processes and even results in foreign policy and diplomatic exchanges, particularly in the domain of global arms control, disarmament and nuclear non-proliferation.

In line with this exploration of the role of non-state actors in space diplomacy, Nancy Riordan, Miloslav Machoň and Lucia Csajková conduct qualitative research based on expert interviews and document analysis to gain insight into the involvement of actors responsible for the negotiations that led to the Artemis Accords.⁶⁷ Their analysis deals with diplomatic communication and elaborates actors’ institutional backgrounds and professional affiliations. They conclude that pre-existing relationships, trust and shared understandings among appointed federal officials and their international counterparts from like-minded countries determined the dynamics of the negotiations that led to the Artemis Accords, and therefore epistemic outputs supported the negotiations but did not shape them directly.

Coming full circle back to science space diplomacy in its truest form, Mariel Borowitz delves into the issue of weather satellites.⁶⁸ Over the past 70 years, the world has established an impressive history of international co-operation on weather monitoring via satellite, but this co-operation has not been consistent. Multilateral co-operation on this topic emerged early in the space age, and weather satellites were also the topic of bilateral engagement between the United States and the Soviet Union during the Cold War. However, more recently, the United States has struggled to maintain its contributions to the global weather monitoring system and has rejected potential opportunities for bilateral co-operation with China in this area. This article investigates the variation in diplomatic efforts in this area and demonstrates that to understand these trends, we must examine the key actors involved in diplomacy on this topic, their motivations, and the processes they use to engage in diplomacy.

Again, in nearly every contribution the importance of persuasion and communication is front and centre, historically and today, regardless of whether the issue resonates more with the economic, scientific or military space diplomacy realms. At the same time, several contributors find in their research that there are contextual conditions that could either diminish or enable the impact of diplomatic persuasion. For example, Li and Mayer argue that institutional density is a key intermediate variable.⁶⁹ Borowitz finds that even the weather can become politicised over time, making the context for space diplomacy to take place a bit more fraught.⁷⁰ Riordan, Machoň and Csajková argue that trust and shared understandings are needed among space diplomacy interlocutors, while Stewart and Dittmar find that the integration of actual space materials tends to lock in co-operative outcomes.⁷¹

Of course, the success of space diplomacy is not unidirectional. What once worked could later fail. As Micah Lowenthal argues, when it comes to science diplomacy, if it is conducted without ulterior motives it is more likely to work.⁷² But this can change. After all, genuine efforts to engage in space diplomacy with the aim of achieving international co-operation have failed, as in the case of the US-China relationship. Politicisation of existing scientific efforts can cause collaboration to deteriorate as scientists start to lose trust in each other.⁷³And if the actors involved are private corporations, individuals or other non-state actors, prioritising goals above scientific discovery could also lead to less co-operation in space.

In this sense, our four practitioners’ perspectives at the end of this special issue are a crucial reminder of the need to actively work on achieving successful space diplomacy in day-to-day interactions. On the one hand, as former head of the European Space Agency Jan Wörner cautions, even with the best intentions, co-operation can become bogged down by national self-interest, slowing progress in this area.⁷⁴ On the other hand, Rick Sturdevant, Space Training and Readiness Command (STARCOM) historian, documents the successes of US efforts to engage in military space diplomacy and achieve international co-operation even when national interests are at stake.⁷⁵ From an astronaut’s perspective, Naoko Yamazaki, an astronaut for Japan’s space agency, emphasises the value of diplomacy in space among those few who have actually experienced it.⁷⁶ Looking to the future, Frank White, the originator of the Overview Effect idea — the psychological and emotional transformation that occurs when astronauts see Earth from outer space — emphasises the potential gains from inculcating a common human outlook through sending more and more people to space to experience this for themselves.⁷⁷

5 Conclusion

Space diplomacy is a valuable lens through which to understand developments in space more generally. As space becomes increasingly indispensable to daily life on Earth, being able to forecast the extent to which it promotes peaceful interactions across borders versus conflict and nationalistic militarism will allow policy-makers to prepare for future scenarios.

Russia’s February 2022 invasion of Ukraine, for example, seemed to initially threaten the continued operations of the ISS. Astronauts from the United States, Russia and Europe were in orbit, living and working on the space station, at the same time that Russian troops marched into Ukraine and attempted to topple the government in Kyiv. However, despite Russian threats to derail the ISS, co-operation continued. Diplomacy in space, on board the ISS, was never in question — astronauts, as quintessential space diplomats, function as a close-knit team with years of common experience — but there was a sigh of relief when the American astronaut Mark Vande Hei returned to Earth on a Russian Soyuz spacecraft alongside two cosmonauts without incident. And the ISS continued to function normally. Future work will certainly uncover the space diplomacy that occurred behind the scenes to make this happen, and these lessons will be indispensable as humans continue to develop a thriving space economy at home, set up a permanent presence on the Moon and go on to Mars.

Overall, this special issue provides an in-depth picture of the main drivers of and obstacles to space diplomacy, which will likely determine the nature of human interaction with and in space for the foreseeable future. Understanding the form and function of space diplomacy also has a bearing on how international relations more generally is evolving in the context of new technologies, new spheres of human activity in the natural world, and the challenge of trying to engage peacefully in a domain where national appropriation is prohibited.⁷⁸