The European Space Agency (or ESA) is an intergovernmental organization that oversees space science and exploration. The ESA comprises 22 European countries that pool financial and scientific resources and are committed to the development of Europe’s space capabilities. Through space exploration and space science experimentation, the ESA seeks to expand the boundaries of knowledge and technology.

The European Space Agency has continuously added member states since it was first founded in 1975—most recently with the signing of Estonia and Hungary in 2015. As of 2018, the European Space Agency employs about 2,200 staff members and for the 2020 fiscal year operates on a budget of €6.68 billion. The current Director General of the ESA is Johann-Dietrich Wörner.

There are currently 22 official ESA member states: Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, and the United Kingdom.

In addition to the official ESA member states, Latvia and Slovenia are associate ESA members. Six other European countries also take part in projects through cooperation agreements with the ESA; these are Bulgaria, Croatia, Cyprus, Lithuania, Malta and Slovakia. Despite the fact that Canada isn’t located in Europe, it too has a cooperation agreement with the ESA and sits on the ESA’s governing council.

The ESA has physical sites in numerous European countries, with each site responsible for different tasks.

• ESA Headquarters: Located in Paris, France, ESA’s homebase is where it forms its policies and programs.
• European Astronaut Centre (EAC): Located in Cologne, Germany, this is the home of ESA astronaut training.
• European Space Operations Centre (ESAC): Located near Madrid, Spain, this is the ESA’s center for astronomy and space science.
• European Space Operations Centre (ESOC): Located in Darmstadt, Germany, ESOC is the ESA’s primary mission control center.
• ESA Centre for Earth Observation (ESRIN): Located in Frascati, Italy, this facility is ESA’s earth observation center.
• European Space Research and Technology Centre (ESTEC): Located in Noordwijk, the Netherlands, this is ESA’s home for space technology and satellite testing.
• European Centre for Space Applications and Telecommunications (ECSAT): Located in Harwell, England, this is an ESA research center that focuses on space telecommunications.

The history of the European Space Agency begins in the 1960s.

• Precursors: In the early 1960s the space race between the United States and the Soviet Union was in full swing. In order to have any chance at competing in the field of spaceflight with these two superpower nations, European scientists realized that they’d need to join forces and combine resources with scientists in other European countries. In 1962 a collective of European nations formed two different space agencies: the European Launcher Development Organisation (ELDO), which built satellite launch systems, and the European Space Research Organisation (ESRO), which pursued space science research and developed spacecraft.
• Origin of ESA: Over its first 10 years ESRO rose to prominence in the field of space exploration, while ELDO never had the same success due to an array of technological setbacks, political disputes, and lack of funding. In 1975, ELDO’s struggles prompted the merger of the two agencies into one, and thus the European Space Agency was born with 10 founding countries.
• Collaboration with NASA: Shortly before the ESA’s creation, ESRO partnered with NASA to create a reusable laboratory to use on space shuttle flights called “Spacelab.” Due to this partnership, NASA soon invited the ESA to submit astronaut applications to NASA. This led to the creation of the European Astronaut Corps.
• Human spaceflight: In the late 1970s and 1980s, European astronauts went on to fly in several NASA space shuttle missions and Russia’s Soyuz missions. Notable ESA astronauts were Switzerland’s Claude Nicollier and Germany’s Thomas Reiter. Nicollier flew two missions to service the Hubble Space Telescope and was the first ESA astronaut to do a spacewalk during a space shuttle mission. Reiter was the first German astronaut to perform a spacewalk and the first European astronaut to join the crew on the International Space Station.

The major responsibilities of the ESA include: building rockets and satellites, launching rockets and satellites, training European astronauts, conducting earth observation, and exploring the solar system. Here are some recent major ESA accomplishments along with some of the ESA’s plans for the future.

• Columbus science laboratory: The ESA built the Columbus science laboratory, which is the ESA’s largest single contribution to the International Space Station. Columbus launched to the ISS aboard Space Shuttle Atlantis in 2008.
• LISA Pathfinder: In 2015 the ESA launched the LISA (Laser Interferometer Space Antenna) Pathfinder spacecraft onboard Vega flight VV06. The purpose of the LISA is to test technology needed for an ESA gravitational wave observatory that the ESA plans to launch in 2034 with the goal of measuring ripples in spacetime.
• ExoMars program: The ESA is searching for evidence of life and water on Mars through their ExoMars program. The first part of this program—a collaboration with Russia—was the 2016 launch of the Trace Gas Orbiter satellite into Mars’ orbit. The next science mission of the ExoMars program is planned for 2022 and will send a rover to the red planet in order to explore and drill for rock samples.
• Galileo GPS: The ESA built the Galileo GPS navigation system so that European nations don’t need to rely on American or Russian GPS systems (which European countries are unable to control). The first Galileo satellites went live in 2016 and the ESA expects Galileo to be fully operational by the end of 2020.
• BepiColombo mission: In 2018 in partnership with the Japan Aerospace Exploration Agency (JAXA), the ESA launched the BepiColombo mission to Mercury on an Ariane rocket. The goal of the BepiColombo mission is to study Mercury’s magnetic field, interior structure, and surface structure. The BepiColombo will arrive on Mercury in December 2025 after it first performs a flyby of Earth, two flybys of Venus, and six flybys of Mercury.
• Ariane 6 and Vega-C rockets: The ESA is currently improving the design of their next generation of rockets: the Ariane 6 and Vega-C. The ESA develops and launches its own rockets to ensure that Europe has autonomous access to space.
• European Service Module: The ESA is currently building the European Service Module, which will power NASA’s Orion spacecraft that’s expected to launch in November 2021 as part of the new Artemis program.
• ATHENA mission: The ESA is preparing to launch the ATHENA (Advanced Telescope for High-Energy Astrophysics) mission in 2031 as part of its Cosmic Vision Program. The ATHENA is an X-ray space telescope that the ESA will use to study hot gas structures and search for supermassive black holes.