At least 14 space agencies have identified ‘in situ resource utilization’ as a necessary capability for long-duration missions, including crewed missions to the Moon, Mars and deep space. Attention is focused on the potential production of rocket fuel from ice and water-bearing minerals. If fuel can be sourced in space, it will not need to be lifted, at great expense, from Earth’s surface. But while the mining of asteroids and other celestial bodies offers benefits, it will also create risks. Mining that is motivated purely by resource extraction could overlook or even destroy important scientific information, while physical interactions with an asteroid could alter its trajectory and, in some circumstances, potentially create a human-caused Earth impact risk. There are presently two competing efforts to develop widely agreed rules on space mining. The first is an industry-friendly effort in which the United States is engaging in bilateral negotiations with dozens of states, encouraging them to sign the non-binding Artemis Accords. The second is a multilateral effort that fully considers the interests of non-spacefaring states and is taking place in the United Nations Committee on the Peaceful Uses of Outer Space.

Humanity’s ascent into space began in 1929 when the German Army tested its first rocket, the A-1. But while militaries have always accounted for a large portion of human space activity, their use of the space environment has been constrained by a mutual self-interest in preserving access to it for communications, navigation, reconnaissance, weather forecasting, arms control verification and early warning. In 1962, the ‘Starfish Prime’ nuclear test demonstrated that nuclear explosions in space pose a major and indiscriminate threat to satellites. This prompted the United States and the Soviet Union to negotiate the 1963 Limited Test Ban Treaty, which prohibits nuclear tests in space. This chapter addresses such tensions between the expansion of military capabilities in space and the need to keep space free of direct conflict. The chapter highlights the growing need for a treaty to ban the testing of ‘kinetic’ anti-satellite weapons, i.e. weapons that rely on violent impacts to destroy a satellite and thus create space debris. Although Russia tested such a weapon in November 2021, the very next month the United Nations General Assembly created an ‘Open Ended Working Group on Reducing Space Threats through Norms, Rules and Principles of Responsible Behaviours’. The chapter concludes with an examination of the potentially destabilising effects of an imminent extension of military activities to cis-lunar space, the region between Earth and the Moon, including special Moon–Earth orbits.

This chapter starts from the proposition that legal substance may be inherently connected to legal form. In particular, consideration is given to the claim that individualistic norms tend to be manifested in highly administrable rules while altruistic norms lend themselves to expression as standards in the legal system. An examination of specific standards in the international legal order that provide a regulatory space for altruism ensues. In doing so, the chapter builds on the insights offered in the previous chapters on substantive international law and reveals that there are certain common legal vehicles through which altruism is compelled or promoted by the law. In a context where the altruistic behaviour of individual states waxes and wanes, the chapter concludes by making a call for greater institutionalisation of altruism.

This chapter considers how certain values may come to shape the law. It explores the institutions, processes and actors that facilitate the emergence of altruistically oriented legal norms. In doing so, the link between ideology and law will become more apparent. The evolution in international law presented in this book is the product of an underlying cosmopolitan altruistic ideology which coexists with a statist individualistic ideology that shape the content of legal rules. A legal system can be influenced by one or more philosophical ideologies, and the international legal system has been and continues to be shaped by different variations of these two major ideologies. As such, cosmopolitan altruism and statist individualism have a dialectic existence in the formation of law and its interpretation. Despite the fundamental differences in the nature and effect of these ideologies, they are capable of having simultaneous normative influence on the behaviour of states and the formation of international law.

This chapter attempts to assess whether and to what extent international law can be seen as governing intra-state peace agreements; and, by turning to the practice of negotiating such agreements, whether international legal obligations, such as with respect to the inclusion of civil society actors, have emerged or are currently emerging. Demonstrating that there exist complex relationships between the practice reflected in peace agreements and international law, the chapter argues that when trying to understand these relationships, much depends on our theoretical stance vis-à-vis international law. Relying on an interactional and pluralistic conception of law, this chapter emphasises the relevance of process-related obligations and the continuous creation and adjustment of legal norms. Finally, the chapter considers the reasons why it might be desirable to ground the practice of peace agreements in international law and to allow this practice to contribute to the development of international law.

This chapter introduces the debates regarding the development of jus ad bellum, with a particular focus on the development of the definition of force and the right to self-defence. It discusses the relationship between the rules of the UN Charter and customary international law, and the way in which development of custom, as well as debates amongst other international actors, contribute to the dynamic interpretation of the Charter rules.

This concluding chapter argues that conventional approaches addressing the development of customary international law relating to the use of force are unable to make sense of the changing practices and technologies that are explored throughout the book. It is argued that rather than focusing on an ambiguously defined requirement of publicity, practice will meet the minimum qualitative requirement as soon as it is publicly known and acknowledged. The chapter further highlights how methodological choices relating to the positioning within international lawmaking of covert operations that are publicly known contribute to the creation of spaces for a range of actors seeking to influence the development of the law. By positioning some acts as ‘outside’ of the international lawmaking process, it leaves open new opportunities to decide what the acts are, and how they should be responded to.

This chapter focuses on the development of customary international law and unpacks the requirement of publicity for state practice. It introduces the different levels of publicity and covertness, and closely examines the role of acknowledgement, justifications, and public knowledge within the requirement of publicity in the light of various approaches to the development of (customary) international law. The chapter illustrates how the requirement of publicity can be unpacked into two main parts, where the first relates to how a state communicates its understanding of its practice in relation to international law, and the second relates to how the act itself and — if available — the justifications provided for it, are known and reacted to by other states and international actors.

This chapter demonstrates how covert operations differ significantly in their level of publicity, and range from acts that remain secret, to acts that are the object of debates amongst states, legal scholars, and civil society, in and outside the settings of international organisations. It is demonstrated that unacknowledged acts can affect the law in different ways depending on their level of publicity and covertness. It will also be shown that the necessity of the involvement of states in a debate around an operation can vary depending on the rule that it is informing. An unacknowledged act leading to extensive academic debate might prove very informative and play an important role in updating the already vague definition of ‘force’ in light of technological developments, but it would not have the same effect if arguing for a right to preventive self-defence against non-imminent threats, where states have been more active in the debate. It is further argued that the absence of states from certain events and debates opens up more influential participation by other international actors, such as legal scholars and other groups of experts.

This introductory chapter intsroduces the themes, context, and structures of the book.