In the aftermath of the Second World War, space technologies became an important area of development for the leading world powers. The Sputnik shock in 1958—when the Soviet Union proved that they could put a satellite into orbit—and the moon landing achieved by the United States were important technological milestones. They were also major events in the Cold War context, serious evidence that both sides had access to, and knew how to use, cutting-edge technology, strengthening the leadership status of both sides vis-à-vis their allies. Such endeavours required substantial resources which were not available to medium powers such as France and Britain. They also understood clearly that the formidable costs of a fully fledged space programme could not be borne by any one of them alone. However, just as for nuclear capabilities, both Britain and France realised that such key technologies were indispensable for them, for reasons which will be analysed in detail in the main text. Against this background, this paper will trace out the progress of the early bilateral cooperation which finally led to the wider project of the European Space Agency.