The lift - off scheduled for this morning has been delayed because of a fuelling problem detected in the third stage of the rocket's fuel tanks.
The Soyuz together with the two satellites and the launch facility have been put into safe mode. The new launch date should be announced within 24 hours.
A contract was signed in 2003 with the Russian space industry to bring in both revenue to their programme and also to provide a dependable launch vehicle.
This launch will be the first of the Galileo project. The programme is for the launch of a total of 27 operational satellites and three spares by it's completion in 2020.
Once detached from the launch vehicle they will remain in geo-stationary position providing Global Positioning System (GPS) to within a metre (3.25 feet) and is based on the US system which became operational in 1995 being upgraded from it's current accuracy between three and eight metres ( 10 - 26 feet), according to official websites.