European Space Agency

The treaty establishing the European Space Agency reads:

"The purpose of the Agency shall be to provide for and to promote, for exclusively peaceful purposes, cooperation among European States in space research and technology and their space applications, with a view to their being used for scientific purposes and for operational space applications systems."

ESA is responsible for setting a unified space and related industrial policy, recommending space objectives to the member states, and integrating national programmes like satellite development, into the European programme as much as possible.

Jean-Jacques Dordain—ESA's Director General (2003–2015)—outlined the European Space Agency's mission in a 2003 interview:

"Today space activities have pursued the benefit of citizens, and citizens are asking for a better quality of life on Earth. They want greater security and economic wealth, but they also want to pursue their dreams, to increase their knowledge, and they want younger people to be attracted to the pursuit of science and technology. I think that space can do all of this: it can produce a higher quality of life, better security, more economic wealth, and also fulfill our citizens' dreams and thirst for knowledge, and attract the young generation. This is the reason space exploration is an integral part of overall space activities. It has always been so, and it will be even more important in the future."

At the ministerial council of 2025, ESA member states widened the agency's mandate to include defence. The resolution reads:

"ESA's intergovernmental framework provides the credentials and tools for developing space technologies and systems [...] for security and defence and to implement corresponding activities."

After World War II, many European scientists left Western Europe to work with the United States. Although the 1950s boom made it possible for Western European countries to invest in research and specifically in space-related activities, Western European scientists realised solely national projects would not be able to compete with the two superpowers. In 1958, only months after the Sputnik shock, Edoardo Amaldi (Italy) and Pierre Auger (France), two prominent members of the Western European scientific community, met to discuss the foundation of a common Western European space agency. The meeting was attended by scientific representatives from eight countries.

The Western European nations decided to have two agencies: one concerned with developing a launch system, ELDO (European Launcher Development Organisation), of which Renzo Carrobio di Carrobio became the first Secretary General from 1964 to 1971, and the other the precursor of the European Space Agency, ESRO (European Space Research Organisation), led by Pierre Auger. The latter was established on 20 March 1964 by an agreement signed on 14 June 1962. From 1968 to 1972, ESRO launched seven research satellites, but ELDO was not able to deliver a launch vehicle. Both agencies struggled with the underfunding and diverging interests of their participants.

The ESA in its current form was founded with the ESA Convention in 1975, when ESRO was merged with ELDO. ESA had ten founding member states: Belgium, Denmark, France, West Germany, Italy, the Netherlands, Spain, Sweden, Switzerland, and the United Kingdom. These signed the ESA Convention in 1975 and deposited the instruments of ratification by 1980, when the convention came into force. During this interval the agency functioned in a de facto fashion.

ESA launched its first major scientific mission in 1975, Cos-B, a satellite monitoring gamma-ray emissions in the universe, which was first worked on by ESRO. ESA collaborated with NASA on the International Ultraviolet Explorer (IUE), the world's first high-orbit telescope, which was launched in 1978 and operated successfully for 18 years. A number of successful Earth-orbit projects followed, and in 1986 ESA began Giotto, its first deep-space mission, to study the comets Halley and Grigg–Skjellerup. …

The agency's facilities date back to ESRO and are deliberately distributed among various countries and areas. The most important are the following centres:

Every member state must contribute to the mandatory programmes. The contributions to the mandatory programmes are calculated based on the states' Gross National Product. Decisions about these programmes are taken unanimously.

Depending on their individual choices, the member states can contribute to optional programmes.

Member states participate to varying degrees with both mandatory space programmes and those that are optional. As of 2008, the mandatory programmes made up 25% of total expenditures while optional space programmes were the other 75%. The ESA has traditionally implemented a policy of "georeturn", where funds that ESA member states provide to the ESA "are returned in the form of contracts to companies in those countries."

By 2015, the ESA was an intergovernmental organisation of 22 member states. The 2008 ESA budget amounted to €3.0 billion whilst the 2009 budget amounted to €3.6 billion. The total budget amounted to about €3.7 billion in 2010, €3.99 billion in 2011, €4.02 billion in 2012, €4.28 billion in 2013, €4.10 billion in 2014, €4.43 billion in 2015, €5.25 billion in 2016, €5.75 billion in 2017, €5.60 billion in 2018, €5.72 billion in 2019, €6.68 billion in 2020, €6.49 billion in 2021, €7.15 billion in 2022, €7.46 billion in 2023, €7.79 billion in 2024 and €8.26 billion in 2026

English and French are the two official languages of the ESA. Additionally, official documents are also provided in German and documents regarding the Spacelab have been also provided in Italian. If found appropriate, the agency may conduct its correspondence in any language of a member state.

The following table lists all the member states and adjunct members, their ESA convention ratification dates, and their contributions as of 2026:

Previously associated members were Austria, Norway, Finland and Slovenia, all of which later joined the ESA as full members. Since March 2026 there have been five associate members: Latvia, Lithuania, Slovakia, Cyprus and Canada. The four European members have shown interest in full membership and may eventually apply within the next years.

Latvia became the second current associated member on 30 June 2020, when the Association Agreement was signed by ESA Director Jan Wörner and the Minister of Education and Science of Latvia, Ilga Šuplinska in Riga. The Saeima ratified it on 27 July.

In May 2021, Lithuania became the third current associated member. As a consequence its citizens became eligible to apply to the 2022 ESA Astronaut group, applications for which were scheduled to close one week later. …