BBC News: Two hundred years later, the general principle of using clocks to aid navigation still stands. But the latest generation of timepiece, to be launched into space onboard the Giove-B satellite, is a world away from Captain Cook's.

"Such a clock has never been flown," Pierre Waller, an engineer at the European Space Agency (Esa), told BBC News.

The beating heart of Giove-B, the second test spacecraft for Europe's Galileo global satellite-navigation system, is a hydrogen maser atomic clock.

Following its launch from the Baikonaur Cosmodrome in Kazakhstan, it will become the most precise time piece to orbit the Earth. It will be accurate to one billionth of a second per day, or one second in three million years.