Sentinel-3 is a Low Earth Orbiting mission to support services relating to the marine and global land environment, with capability to serve further atmospheric- and cryospheric-based application areas. The first Sentinel-3 satellite is expected to launch in 2014, followed by a second, so they work together to provide maximum coverage.

Sentinel-3
Mission Overview The mission's main objective is to determine, with high-end accuracy and reliability, parameters such as sea-surface topography; sea- and land-surface temperature and ocean- and land-surface colour.	Instruments From a high-inclination Sun-synchronous polar orbit, at 814.5 km over geoid, the pair of operational Sentinel-3 satellites will provide global coverage in two days. Each satellite has an approximate seven-year operational life span, with consumables for up to 12 years.
Services From a high-inclination Sun-synchronous polar orbit, the pair of operational Sentinel-3 satellites will provide global optical coverage in two days. Near-real time data processing and delivery will allow a broad range of GMES services for both the marine and land environment.	Resources A collection of technical and scientific documentation relating to the Sentinel-3 satellites.