Sentinel-1
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Sentinel satellites enter era of 'Big Data'

The EU's Sentinel Earth-observation system is now delivering prodigious amounts of data, according to the European Space Agency.

And with just three spacecraft launched so far in what will eventually be a multi-billion-euro, multi-sensor network, the demand from users has already exceeded expectation.

Esa's director of Earth observation, Volker Liebig, spoke with our correspondent Jonathan Amos on the eve of the launch of the latest satellite to go into orbit - Sentinel-1b.