Sentinel-3 is primarily an ocean mission composed of three versatile satellites. However, the mission will also be able to provide atmospheric and land applications. The mission will provide data continuity for the ERS, Envisat and SPOT satellites.
Sentinel-3 will make use of multiple sensing instruments to accomplish its objectives; SLSTR (Sea and Land Surface Temperature Radiometer), OLCI (Ocean and Land Colour Instrument), SRAL (SAR Altimeter), DORIS, and MWR (Microwave Radiometer).
SLSTR and OLCI are optical instruments that will be used to provide data continuity for Envisat's MERIS and AATSR instruments and the swath's of the two instruments will overlap, allowing for new combined applications. OLCI is a medium-resolution imaging spectrometer, and the instrument uses five cameras to provide a wide field of view.
SRAL, DORIS, MWR and LRR will be used for topographic measurements of the ocean and in-land water. The SRAL altimeter will be the main topographic instrument. The MWR radiometer will measure water vapour and cloud water content and the thermal radiation emitted by the Earth.
The observations acquired by the mission will be used to in conjunction with other ocean-observing missions to contribute to the Global Ocean Observing System (GOOS) which aims to create a permanent system of ocean observation.
In July 2009, ESA conducted an airborne campaign, Sen3Exp (Sentinel-3 Experiment) to test the land and ocean imaging applications of the Sentinel-3 mission using three instruments; AHS (Airborne Hyperspectral System), CASI-1500i (Compact Airborne Spectrographic Imager) and SASI-600 (Shortwave Infrared Airborne Spectrometer). Satellite observations were also made by Envisat's MERIS and AATSR instruments, which are similar to Sentinel-3's SLSTR and OLCI instruments, and the CHRIS instrument aboard Proba-1.
Planned Launch Date:
Orbit Type: Sun-synchronous
Resolution and Swath Width:
In addition to the observation instruments, the Sentinel-3 spacecraft will carry the GNSS (Global Navigation Satellite System) and LRR (Laser Retro Reflector) instruments. GNSS will provide precise orbit determination and can track multiple satellites simultaneously. LRR will be used to accurately locate the satellite in orbit using a laser ranging system.
The dimensions of the craft are: 3.7 x 2.2 x 2.2 m with a weight (at time of launch) of 1250 kg.
Thales Alenia Space is the prime contractor, responsible for constructing the spacecraft and the SRAL instrument, as well as contributing to the supply of the SLSTR instrument.