European Space Agency
Inter-governmental space agency operating Earth observation programmes including Sentinel, EarthCARE, and Aeolus.
The European Space Agency (ESA) is an intergovernmental organisation established on 30 May 1975 under the ESA Convention, formed from the merger of the European Space Research Organisation (ESRO) and the European Launcher Development Organisation (ELDO).[^esa-history] Headquartered in Paris with its primary technical centre at ESTEC in Noordwijk (Netherlands) and its Earth observation operations centre at ESRIN in Frascati (Italy), ESA brings together 23 full member states and five associate members as of 2025-2026.[^wikipedia]
ESA's Earth observation programme operates through four principal lines: the Copernicus programme, the FutureEO programme (Earth Explorers and Scouts), Heritage Missions, and Third Party / Copernicus Contributing Missions.[^earth-online] Within Copernicus, Europe's civil Earth observation infrastructure owned and mandated by the European Commission, ESA acts as the Space Segment Development Authority, designing, procuring, launching, and operating the Sentinel satellite family.[^copernicus-esa] Sentinel missions span C-band radar (Sentinel-1), multispectral optical (Sentinel-2), ocean-land monitoring (Sentinel-3), and atmospheric monitoring (Sentinel-5P), among others; EUMETSAT co-operates specific missions including the Sentinel-3 marine data stream and Sentinel-6 ocean altimetry.[^copernicus-eu] Copernicus data is freely available globally through the Copernicus Data Space Ecosystem under an open data policy.[^copernicus-data-space]
Through the FutureEO programme, ESA funds and operates science-driven Earth Explorer missions selected through community consultation, each addressing a distinct geophysical question. As of 2025-2026, seven Earth Explorers are operational or completed and four are in development or assessment.[^futureeo]
ESA does not manufacture satellites itself; industrial development and manufacturing are contracted to European prime contractors including Airbus Defence and Space and Thales Alenia Space. ESA serves as the system authority, setting requirements, managing integration, and conducting launch and early operations. With a total budget of approximately €8.26 billion for 2026 and a staff of approximately 3,000, ESA is the primary institutional operator of European EO infrastructure and the central counterpart for European EO data policy.[^wikipedia]