At the onset of perestroika, space research in the USSR was thriving, as evidenced by the numerous domestic projects and joint international missions undertaken, which indicated promising prospects for the future. The primary research activities were conducted under the Intercosmos program, which facilitated both cooperation between the Soviet Union and the countries of the socialist camp, as well as collaboration with a diverse range of international partners. Notably, joint projects were implemented with various Western European countries, the United States, India, and Australia. The relations with ESA were also developed across various scientific fields. A key factor driving the rapprochement with Western partners in the latter half of the 1980s was the temporary withdrawal of the USSR’s main competitor from the space race. As Western observers noted, following the 1986 Challenger shuttle disaster, the Soviet Union sought to capitalise on this opportunity and seize the initiative. This chapter examines the scientific space projects undertaken during the perestroika period, including those conducted in collaboration with ESA.