The second Sentinel-3 satellite, Copernicus Sentinel-3B, was launched on 25 April, joining its identical twin Sentinel-3A in orbit. This pairing of satellites increases coverage and data delivery for the European Union's Copernicus environment programme.

The 1150 kg Sentinel-3B satellite was carried into orbit on a Rockot launcher from Plesetsk, Russia, at 17:57 GMT (19:57 CEST; 21:57 local time) on 25 April.

Rockot's upper stage delivered Sentinel-3B into its planned orbit.

Just 92 minutes after liftoff, Sentinel-3B sent its first signals to the Kiruna station in Sweden. Data links were quickly established by teams at ESA's operations centre in Darmstadt, Germany, allowing them to assume control of the satellite.

During the three-day launch and the early orbit phase, controllers will check that all the satellite's systems are working and begin calibrating the instruments to commission the satellite. The mission is expected to begin routine operations after five months.