A programme of activities of the European Space Agency (ESA) that requires the participation of all member nations. This includes the space science programme and the agency's general budget. Such activities are funded by contributions from all ESA members according to each country's gross national product. For example, the Hipparcos satellite launched in August 1989 was designated a mandatory programme in 1980.
The alternative to the mandatory programme is the optional programme. The two types of programme were created when ministers in charge of space from ten European nations met in 1973 in Brussels, Belgium, to establish the ESA.