BBC: The sixth Sentinel in Europe's ambitious new multi-billion-euro Earth-observation project has been contracted from industry.
Sentinel-6a will measure changes in the height of the oceans - a key indicator for understanding weather and climate.
The European Space Agency (Esa) signed the 177m-euro (127m) deal with Airbus Defence and Space at a remote-sensing symposium in Berlin, Germany.
Sentinel-6a should be ready for launch in 2020.
It will ensure the continuity of a data-set that stretches...