(CNN) -- A Soyuz rocket was launched Friday morning from a European space base in South America after a delay over a fueling hitch.
The rocket launched just after 6:30 a.m. ET.
The Russian-built Soyuz is hauling the first two satellites of a planned rival to the United States' Global Positioning System -- a major milestone for the European space industry.
The satellites weigh about 700 kilograms (1,543 pounds) each and form the operational nucleus of Europe's 30-satellite Galileo navigation constellation, launch operator Arianespace said.
"Satellite positioning has already become the standard way of navigating," the European Space Agency said. " If the signals were switched off tomorrow, many ship and aircraft crews would find it inconvenient and difficult to revert to traditional navigation methods."
European users currently rely on the GPS or Russian Glonass satellites, the agency said.
Scientists delayed the launch a few hours before liftoff Thursday after they detected a problem during fueling at the base in French Guiana, according to the agency.
Soyuz's flight is the first to depart from European territory in Kourou, French Guiana.
"October's launch will be doubly historic: the first Soyuz from a spaceport outside of Baikonur in Kazakhstan or Plesetsk in Russia and the start of building Europe's Galileo satnav constellation," the agency said in a statement released before the launch.
The Galileo navigation constellation is a collaborative effort between the European Space Agency and the European Union. The space agency said it plans to launch four operational satellites in 2011 and 2012.