LONDON — European transport ministers meeting in Luxembourg have sanctioned additional public finance to ensure the troubled Galileo satellite navigation network is built, but put off tackling the question of exactly where the extra taxpayer money will come from.

Last month, the European Commission urged member states to find the funds after the industrial consortium chosen to build and operate the satellite navigation system failed to reach terms.

The consortium — which includes European aerospace giant EADS; France's Thales and Alcatel-Lucent; Britain's Inmarsat; Italy's Finmeccanica; Spain's AENA and Hispasat; and a German group led by Deutsche Telekom — proved reluctant to take on the economic risks, and missed the deadline to come forward with a single company structure to run Galileo.

The project had become bogged down by private sector squabbles and member states pushing individual industrial interests.

Under new proposals for the future development of Galileo, these companies will now be offered the opportunity to run the system — but only after the public sector has built it.

All 27 ministers approved the plan, which will require an initial outlay of Euros 2.4 billion ($3.2 billion) of public money towards the project's total cost of about 4 billion euros.

This is in addition to the Euros 1.3 billion governments have already committed to Galileo, seen as Europe's answer to the U.S.-operated global positioning system GPS.

Agreeing that the project "would need additional public funding" to be operational by 2012, the ministers tasked the EC with working out financing details before their next meeting in October.

German Transport Minister Wolfgang Tiefensee said after the meeting Galileo was of "colossal importance" to Europe, adding: "We must prove our worth in this field of technology in competition with the U.S., Russia and Asia."

But Tiefensee added there was no agreement whether the money to plug the Euros 2.4 billion shortfall should come from EU states or the Community's collective budget, and that ministers were still open to private funding, if any was offered.

"We realized that the concession-based model was heading nowhere," the German Transport Minister said.

"For that reason we want to try out all the possibilities of public sector financing including financing via the European Space Agency," he added, referring to the initiative's other major backer, which oversees Europe's space program.

The first demonstrator spacecraft, Giove-A, is already in orbit. A second, Giove-B, which has had some technical problems, should be in orbit by the end of this year.

The contract for the first four commercial satellites in the final constellation was awarded at the end of 2004. Under the new arrangement, the public sector would now order the remaining 26.