The Copernicus Sentinel-3B satellite spent six weeks at the Plesetsk cosmodrome in Russia being carefully prepared for liftoff. After being shipped from France to the launch site, the satellite was tested, joined to the rocket launch adapter, sealed from view in the fairing and taken by train to the launch pad. Sentinel-3B lifted off on 25 April 2018 at 17:57 GMT (19:57 CEST). 

It joins its twin, Sentinel-3A, in orbit. The pairing of identical satellites provides the best coverage and data delivery for Europe’s Copernicus programme – the largest environmental monitoring programme in the world. The satellites carry the same suite of cutting-edge instruments to measure oceans, land, ice and atmosphere. While these data are fed primarily into the Copernicus Marine Environment Monitoring Service, all the Copernicus services benefit to produce knowledge and information products in near-real time for a wide range of applications. The Sentinel-3 mission is essential for applications for ocean and coastal monitoring, numerical weather and ocean prediction, sea-level change and sea-surface topography monitoring, ocean primary production estimation and land-cover change mapping.