The European Union on Sunday is to launch the second satellite in its much-delayed Galileo navigation system designed to rival the American GPS system.
The experimental satellite will be fired into space on a Russian Soyuz rocket from the Baikonur cosmodrome in Kazakhstan in the early hours of Sunday morning.
Named Giove-B, the satellite will test technologies to be used in the Galileo system including an atomic clock that the EU says will be the most accurate in space.
Touted as technologically superior to GPS, Galileo is scheduled to be operational by 2013 but has encountered delays. Its first satellite was launched in 2005, but the second missed its late 2006 launch due to a short-circuit problem in final testing.
Senior EU officials will monitor the launch of Giove-B from the Fucino control center in central Italy.
Late last year, European Union governments had to agree to a taxpayer bailout after a consortium of private companies from France, Germany, Spain, Britain and Italy walked away from the project in a financing dispute.
The cost of setting up the final network of 20 satellites is expected to be euro3.4 billion (US$5.3 billion). At least euro1 billion (US$1.56 billion) of taxpayers' money has already been spent on it.
Galileo promises to more than double existing GPS coverage, providing navigation for motorists, sailors, pilots and emergency rescue teams. It would improve coverage in high-latitude areas such as northern Europe, and in big cities where skyscrapers can block signals.