The European Space Agency (ESA) is an intergovernmental organization of 22 member states dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA had a worldwide staff of about 2,200 in 2018 and an annual budget of approximately €5.6 billion (~US$7 billion) in the same year.

ESA’s spaceflight program includes human spaceflight (mainly through participation in the International Space Station program), the launch and operation of unmanned exploration missions to other planets and the Moon, Earth observation, science, and telecommunications. It also involves designing launch vehicles and maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana. The main European launch vehicle, Ariane 5, is operated through Arianespace, with ESA sharing in the costs of launching and further developing this vehicle. The agency is also collaborating with NASA to manufacture the Orion Spacecraft service module, which will fly on the Space Launch System.

ESA’s facilities are distributed among the following centers:

•ESA science missions are based at ESTEC in Noordwijk, Netherlands.

•Earth observation missions are handled at the ESA Centre for Earth Observation in Frascati, Italy.

•ESA Mission Control (ESOC) is located in Darmstadt, Germany.

•The European Astronaut Centre (EAC), which trains astronauts for future missions, is situated in Cologne, Germany.

•The European Centre for Space Applications and Telecommunications (ECSAT), a research institute created in 2009, is located at Harwell, England.

•The European Space Astronomy Centre (ESAC) is located in Villanueva de la Cañada, Madrid, Spain.