Sentinel-3

Sentinel-3
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Name	Sentinel-3
Mission type	Earth observation
Operator	European Space Agency, European Commission
Manufacturer	Thales Alenia Space, Airbus Defence and Space
Launch mass	~1150 kg
Power	~1.2 kW
Orbit	Sun-synchronous
Status	Active

Sentinel-3 Sentinel-3 is a European Union Earth observation satellite series developed under the Copernicus Programme and operated by the European Space Agency and the European Commission. The project delivers routine global measurements of sea surface temperature, ocean colour, land surface temperature, and sea surface topography to support oceanography, climatology, agriculture, and disaster management. Designed as part of an operational constellation, the series complements missions such as Sentinel-1, Sentinel-2, Sentinel-5P, and Jason-3 to provide synergistic datasets for scientific and policy applications.

Overview

Sentinel-3 was conceived within the policy framework of the Copernicus Programme to meet requirements set by the European Commission Directorate-General for Defence Industry and Space and implemented through the European Space Agency procurement and coordination processes. The mission architecture derives heritage from the Envisat and ERS-2 programmes, and aligns with international initiatives like the Group on Earth Observations and the Global Climate Observing System. Orbit selection—a sun-synchronous, near-polar configuration—enables global coverage and frequent revisit times, optimized alongside spaceborne assets such as Landsat 8, MODIS, and VIIRS for cross-calibration and intercomparison.

Spacecraft and Instruments

The Sentinel-3 spacecraft bus was constructed by industrial consortia including Thales Alenia Space and Airbus Defence and Space, integrating avionics and payloads to deliver multi-instrument observations. Key instruments comprise: - The Sea and Land Surface Temperature Radiometer (SLSTR), providing precise infrared and thermal measurements for sea surface temperature and vegetation monitoring, with calibration strategies referencing instruments like Aqua and Terra. - The Ocean and Land Colour Instrument (OLCI), a push-broom spectrometer with heritage links to MERIS that measures reflected radiance across visible and shortwave bands for phytoplankton and water quality retrievals. - A microwave-compatible Synthetic Aperture Radar is not present on Sentinel-3; instead, radar altimetry functions are fulfilled by the European SRAL instrument for precise sea surface height and ice topography mapping, designed to complement the Jason series. - A suite of supporting systems includes the DORIS receiver for precise orbit determination, a Laser Retroreflector Array for satellite laser ranging analogous to systems flown on LAGEOS, and an instrument-level radiometric calibration chain aligned with Absolute Radiometer Calibration practices.

Mission Operations and Data Products

Mission operations are coordinated by the European Space Operations Centre and data processing is managed through the Copernicus Services infrastructure, with ground segments involving national agencies such as the Norwegian Space Centre and the French Space Agency. Data products are classified into Level 0 through Level 3 tiers, delivering time-series and gridded products for sea level rise assessment, Chlorophyll-a concentration mapping, and land surface temperature monitoring. Product suites include sea-surface topography, along-track altimetry, ocean colour mosaics, and fire detection products complementary to datasets from EUMETSAT and the European Organisation for the Exploitation of Meteorological Satellites.

Applications and Scientific Impact

Sentinel-3 datasets underpin operational services like the Copernicus Marine Environment Monitoring Service, the European Drought Observatory, and the Global Monitoring for Environment and Security initiatives. Scientific uses span validation of climate models developed at institutions such as the Met Office, National Oceanic and Atmospheric Administration, and NASA, to ecosystem studies conducted by research centres including the Plymouth Marine Laboratory and Scripps Institution of Oceanography. The mission informs policy addressing sea level rise, coastal erosion, fisheries management, and supports emergency response for events like the 2010 Deepwater Horizon oil spill-style incidents and regional flood mapping used by agencies such as UN-SPIDER and the International Charter on Space and Major Disasters.

Launches and Mission Timeline

The Sentinel-3 programme deployed multiple spacecraft in a phased schedule to establish nominal operations and ensure continuity. Launch vehicles involved include the Rockot and Ariane 5/Vega families via sites such as Guiana Space Centre and Plesetsk Cosmodrome. Key timeline events parallel milestones from heritage missions like Envisat and coordination activities with Jason-3 for tandem sea-level observations. Mission extensions and replacements are planned within the Copernicus Regulation and through follow-on procurements, aligning Sentinel-3 launches with broader constellation refresh strategies executed by suppliers including OHB SE.

International Collaboration and Program Management

Sentinel-3 exemplifies multinational collaboration, coordinated by the European Space Agency in partnership with the European Commission and industry primes including Thales Group and Airbus Group. International interoperability and data policy draw on agreements with organizations such as NOAA, NASA, EUMETSAT, and scientific networks like the International Oceanographic Commission. Program governance follows procurement, quality assurance, and scientific advisory frameworks involving panels from ESA Science Programme Committee and the Copernicus User Forum, ensuring that operational requirements from stakeholders including coastal states, research institutes, and commercial service providers are represented.

Category:Earth observation satellites Category:Copernicus Programme