ESA Earth Explorer program

ESA Earth Explorer program
Name	ESA Earth Explorer programme
Operator	European Space Agency
Country	European Union
Status	Active
First	CryoSat-2

ESA Earth Explorer program

The ESA Earth Explorer program is a series of research satellite missions within the Living Planet Programme that address scientific challenges in Earth science, climate change, atmospheric science, oceanography, and cryosphere studies. Designed and managed by the European Space Agency in partnership with national space agencys, academic research institutes, and industrial contractors, the programme complements operational Earth observation efforts by focusing on targeted process studies, novel instrument concepts, and long-term climate monitoring.

Overview

The programme comprises dedicated research missions such as CryoSat-2, SMOS, Swarm, Aeolus, BIOMASS, and EarthCARE that carry advanced radar altimeter, synthetic aperture radar, radiometer, laser and lidar systems developed by contractors across France, Germany, United Kingdom, Italy, Spain, and Netherlands. Each mission is conceived under the auspices of the European Space Agency Directorate of Earth Observation Programs, with science inputs from organisations such as European Space Research and Technology Centre, European Centre for Medium-Range Weather Forecasts, Max Planck Society, CNES, and DLR. The programme aims to advance understanding of processes relevant to Intergovernmental Panel on Climate Change, World Meteorological Organization, United Nations Framework Convention on Climate Change and regional stakeholders.

History and development

Originating in the late 1990s as part of the Living Planet Programme initiated after recommendations from the Horizon 2000 Plus review, the Earth Explorer series evolved through competitive solicitations, feasibility studies and technology demonstrations guided by panels including the Science Programme Committee and advisory groups from European Research Council and national academies. Early decisions cited heritage from missions such as ERS-1, ERS-2, and Envisat, while responding to needs highlighted by reports from Global Climate Observing System and scientific assessments by the Intergovernmental Panel on Climate Change. Programme milestones include selection of the first Earth Explorer missions in the 2000s, the recovery effort that produced CryoSat-2 after CryoSat failure, and later additions responding to recommendations from the Committee on Earth Observation Satellites and community-led proposals.

Missions and Payloads

Earth Explorer missions span ice, ocean, atmosphere, biosphere and solid Earth themes. CryoSat-2 hosts a pulse-limited and Synthetic Aperture Radar altimeter to measure polar ice thickness; SMOS carries a microwave radiometer to map soil moisture and sea surface salinity; Swarm comprises three magnetic field satellites with vector magnetometers to probe Earth's magnetic field and core dynamics; Aeolus flew a Doppler wind lidar to profile global wind fields; BIOMASS will use a P-band polarimetric radar to estimate forest biomass and carbon stocks; EarthCARE carries cloud profiling radar and multi-spectral imagers to study cloud-aerosol interactions. Payload development draws on expertise from contractors such as Airbus Defence and Space, Thales Alenia Space, OHB SE, RUAG Space, and research groups at University of Oxford, University of Leeds, Institut Pierre-Simon Laplace, and Imperial College London.

Selection and Competition Process

Mission proposals enter ESA’s competitive selection framework via Announcement of Opportunity calls evaluated by peer review panels including representatives from European Space Agency, national space agencys, and scientific bodies like Committee on Earth Observation Satellites and the European Geosciences Union. Selection phases include pre-selection, feasibility study, Assessment Phase, and Mission Adoption, with engineering inputs from European Space Research and Technology Centre and programmatic oversight by the Directorate of Science and Robotic Exploration. Community-driven missions often originate from white papers at conferences such as AGU Fall Meeting, EGU General Assembly, and workshops convened by Global Carbon Project or International Arctic Science Committee.

Science Objectives and Applications

Science objectives target quantification of processes underlying sea level rise, polar ice dynamics, carbon cycle fluxes, atmospheric composition and dynamics, soil moisture variability, and geomagnetic field evolution. Applications extend to improved numerical weather prediction at European Centre for Medium-Range Weather Forecasts, enhanced carbon budget assessments for United Nations Framework Convention on Climate Change reporting, disaster risk reduction for agencies like Copernicus Emergency Management Service, and resource management for forestry and agriculture stakeholders including Food and Agriculture Organization. Results feed into assessment reports by the Intergovernmental Panel on Climate Change and operational assimilation into models at institutions such as Met Office and Météo-France.

Data Access and Processing

Data policy for Earth Explorer missions typically follows open access principles coordinated with ESA’s Earth Online and Copernicus architectures, enabling distribution via payload data centers, mirror sites at national agencies, and repositories hosted by European Space Agency nodes and partners including EUMETSAT and Centre for Environmental Data Analysis. Processing chains produce Level 0 to Level 4 products with algorithms developed by science teams at University of Edinburgh, CNES, DLR, and National Oceanography Centre; validation campaigns involve field sites managed by International Soil Moisture Network and airborne campaigns by institutions such as NERC and French National Centre for Scientific Research.

Collaborations and Partnerships

Collaborations link ESA with national agencies like CNES, DLR, UK Space Agency, ASI, and CDTI, with industrial partners including Airbus, Thales Group, and RUAG, and academic consortia across Europe and international collaborators such as NASA, JAXA, NOAA, and CSA. Partnerships enable instrument contributions, data exploitation, and joint missions or campaigns coordinated through bodies like Committee on Earth Observation Satellites and thematic programmes including GEOSS and Copernicus. The programme’s governance integrates inputs from the European Commission, scientific advisory boards, and user communities spanning research institutes, regional agencies, and non-governmental organisations.

Category:European Space Agency