A model of the Galileo satellite hangs at the German Aerospace Center in Oberpfaffenhofen, near Wessling, Germany | Peter Kneffel/AFP via Getty Images EU goes dark on Galileo satellite outage ’We can’t provide a running commentary,’ official says after EU forced to take satellite navigation system offline.

The EU’s multibillion-euro satellite navigation system Galileo has been down for almost a week — with little explanation.

The Galileo constellation, a €10 billion investment aimed at giving Europe an independent and more accurate alternative to the U.S. Global Positioning System (GPS) system, has been offline after first experiencing problems on Thursday, with no timeline for bringing the navigation service back into operation.

While the agency responsible insists the problem stems from a ground-based station and not the orbiting satellites, it has been quiet on the precise cause.

A team of experts from the agency, along with the Paris-based European Space Agency and the European Commission are investigating possible “recovery actions,” the Prague-based European Global Navigation Satellite Systems Agency (GNSS) said in a statement Wednesday.

A Commission official said a full report would only be issued once the problem is resolved. “On the technical work, on the specifics, we can’t provide a running commentary,” the official said, while insisting that the EU continues to be responsive on the issue.

There is also fear that offering up information could expose vulnerabilities in the nascent Galileo system before they can be fixed.

It’s a major embarrassment for the EU, which has been vocal in pitching its system as a superior alternative to GPS, with around 30 percent better accuracy. It also argues its service provides geopolitical independence should the U.S. system ever become unavailable.

While Galileo’s navigation service is offline, devices are instead relying on data from the American alternative, while GNSS insists that Galileo's emergency rescue operations are working but likely with significantly reduced location accuracy.

With 22 satellites currently in orbit, Galileo funnels navigation and timing data to a host of applications, including millions of mobile phones, with the EU in the process of working to increase the number of applications that are Galileo-compatible.

It counts on two ground control centers at Fucino in Italy and Oberpfaffenhofen in Germany, which calculate and monitor the orbits of the active satellites up to an accuracy of 10 centimeters.

All satellites are currently marked as “not contributing to the service provision,” according to a status report that is updated regularly.

“Operational teams are working on recovery actions 24/7 to restore the Galileo navigation and timing services as soon as possible,” the GNSS statement said. “It is too early to confirm an exact service recovery date.”

Galileo is the fourth system of its kind in orbit, with Russia’s Glonass and China's Beidou also operating. It should ultimately see 30 satellites in space.

Researchers at the Navigation Signal Analysis and Simulation in Torino, a research project, said they have been watching the satellites send increasingly inaccurate positioning signals over the past few days, although there were signs of improvement from late Tuesday.

The reduced accuracy of around 500 meters can only give a rough location, and is useless for the highly accurate positioning required by applications such as mobile phones or the eCall emergency response system, an EU-standard service automatically activated by vehicles in the event of a crash.

The system failure comes as the Commission tries to convince countries to invest around €16 billion in EU space programs including Galileo from 2021 to 2027.

“The key objective is to restore the Galileo navigation and timing services for users as soon as possible,” GNSS said Wednesday.