In the ever-evolving landscape of modern warfare, the significance of space in military operations has reached unprecedented heights. As nations gear up for multi-domain operations, the theatres of battle extend far beyond the traditional land, sea, and airfields. The critical role of space for the defence sector has forced EU member states to upgrade their capabilities in this area. In this paper, we briefly show how the armed forces of European states increased their interoperability in space and the upper atmosphere. To do this, we refer to the new European space commands, the investments of European countries, military exercises concerning the space domain and, finally, the most recent developments concerning European high-atmosphere hypersonic missile interceptors.