Galileo satellite
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Inside one of Europe's new Galileo navigation satellites

The launch of the first satellites in Europe's version of GPS is due to take place on Friday.

The Galileo satellites being sent up on the Soyuz rocket from French Guiana were put together in the UK by EADS Astrium.

James Hinds from the company gave Pallab Ghosh a rare glimpse inside one of them and explained how it works.