ESA has ensured the continuation of the Sentinel-1 Earth observation satellite series for Europe's Copernicus environmental programme by ordering two more satellites.

The €400 million contract was signed today with Thales Alenia Space of Italy to build Sentinel-1C and -1D.

Thales Alenia Space will lead a consortium of 60 European companies, including Germany's Airbus Defence and Space, responsible for the radar instrument.

Launched in April 2014, Sentinel-1A was the first of the dedicated Copernicus series for monitoring the land and oceans, and helping out during natural disasters.

Composed of two polar-orbiting satellites operating day and night, the Sentinel-1 mission provides radar coverage regardless of the weather. The coverage will be boosted following the launch of twin Sentinel-1B next April.