As space develops as a potential war fighting domain, so does the need to have ethical scrutiny. Since the 1960s there have been core space treaties that together with national laws, provide a clear framework for both military and civilian space activities, yet ethical questions still exist around space warfare. Is it appropriate to respond kinetically on earth to a threat in space? Does just war theory apply in space and does the remoteness of space lower or raise the threshold for armed conflicts? Will the creation of new space forces start a space arms race? New combat environments also create a number of new challenges, including whether future war in space will be conducted by robots or space marines, and how the dual-use nature of satellites will impact on their permissibility as targets in any future conflict. As technologies become more widespread, space may be threatened by the likes of non-state groups and rogue states, leading to a need to inhibit their movement in space. In space, differences are magnified; resources are especially scarce, risks are multiplied, and specialized medical care is a world away. The physical and psychological distance between combatants in modern warfare applies also to space and the impacts of remote warfare need to be considered including the potential for moral injury and psychological trauma. With greater military power comes greater responsibility and this responsibility is carried out at the end of a chain of decisions and technologies. This book’s relevancy will not be lost on students at service academies and staff colleges in preparing them for the task of emphasizing ethical responsibility in space to those whom they will lead in the future.