Following its arrival at Russia’s Plesetsk launch site, the Copernicus Sentinel-3B satellite has been removed from its transport container. The satellite will now be prepared for liftoff, scheduled for 25 April 2018. Its identical twin, Sentinel-3A, has been in orbit since February 2016. The two-satellite constellation offers optimum global coverage and data delivery. The mission has been designed to measure systematically Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. It will provide essential information in near-real time for ocean and weather forecasting.