This chapter examines the cooperation between ESA and Soviet space organisations during the period leading up to perestroika. Formally established in 1971, this relationship gave rise to a series of scientific exchanges that paved the way for more active collaboration in the years that followed. After reconstructing the history of joint projects implemented between 1971 and 1985, we will analyse the factors that contributed to the rapprochement between the USSR and ESA, the characteristics of its development, and the key influences that shaped this collaboration. Special attention will be given to the international Halley’s Comet projects, which were initiated during the pre-perestroika era and whose implementation coincided with the early years of Gorbachev’s reforms.