European space policy is currently at a watershed. In 2021, there will be two institutions responsible for European space activities: The EU Space Agency (EU SPA) and the civilian European Space Agency (ESA) founded in 1975. This article investigates how new objectives and governance scheme(s) of European space activities reflect the increasing securitisation of space in Europe. Linking work in critical security studies to the concept of boundary work from science and technology studies (STS) I outline three phases of boundary work – expansion, expulsion and protection of autonomy – that all show how the dividing lines between peaceful and militarised space activities have become increasingly blurred. The conclusion argues that we currently witness a shift in the visions of European integration in space, with ESA remaining outside the EU framework and open to non-EU members while the EU SPA is accessible to EU members only and explicitly dedicated to the use of space for security. As the strategic potential of outer space is likely to grow, the paper offers a critical empirical investigation of the ongoing transformation in European space policy that has significant consequences for how we envision a “united Europe in space”.