Committee on Earth Observation Satellites
Intergovernmental coordination forum for civil space-based Earth observation, established September 1984. Brings together 66 member agencies and associates (NASA, ESA, JAXA, CNES, DLR, and most national civil space agencies) to harmonise EO requirements, validation frameworks, and data interoperability standards. CEOS does not operate satellites, manufacture sensors, or produce data products. Its Working Group on Calibration and Validation (WGCV) hosts the LPV (Land Product Validation) subgroup, which defines the Stage 0-4 land product validation hierarchy used as the authority framework for EO-Atlas calibration gradings.
The Committee on Earth Observation Satellites (CEOS) is the primary intergovernmental forum for coordinating civil space-based Earth observation. Established in September 1984 following a G7 Economic Summit recommendation, CEOS brings together 34 full member agencies and 32 associates - 66 in total - including NASA, ESA, JAXA, ISRO, CNES, DLR, and most national civil space agencies.[^ceos-about]
CEOS does not operate satellites, manufacture sensors, or distribute data products. Its role is coordination and harmonisation: aligning EO requirements across member programmes, establishing interoperability standards, and providing validated calibration and validation frameworks that member agencies adopt.[^ceos-about]
The organisation operates through five working groups. The Working Group on Calibration and Validation (WGCV) is the standards authority for two EO-Atlas entries. Its Land Product Validation (LPV) subgroup, hosted at NASA Goddard Space Flight Center, defines the Stage 0-4 validation hierarchy - the grading scale used across the EO-Atlas calibration layer to classify the maturity of satellite-derived land products.[^ceos-lpv] The Infrared and Visible Optical Sensors (IVOS) subgroup establishes calibration and validation requirements for optical satellite sensors, promoting international standardisation and inter-comparison across test sites.[^ceos-ivos]
CEOS also convenes ten virtual constellations - thematic coordination groups that align member agency satellite assets against shared observation objectives including ocean colour radiometry, land surface imaging, sea surface temperature, and atmospheric composition. The 39th CEOS Plenary, held in Bath in November 2025, added a Biodiversity Virtual Constellation and advanced the CEOS-ARD Strategy 2026.[^ceos-plenary-39]
Governance follows a rotating Chair model. Australia holds the Chair for 2026, succeeding the UK Space Agency. Norway is nominated for 2027. NASA assumed the Senior Interagency Team Chair from JAXA at the 39th Plenary.