Europe’s Galileo satnav hit by multiple clock failures

Europe's bedevilled Galileo satellite navigation network is suffering a number of unexplained clock failures, the European Space Agency (ESA) said on Wednesday.

Jan Woerner, ESA director general revealed there are nine broken clocks on Galileo’s 18 satellites, and the project may experience further delays as the cause of the failure is investigated. "Everybody is raising this question: should we postpone the next launch until we find the root cause, or should we launch?” Woerner said.

The next four satellites are due to launch in the second half of 2017. The full constellation foresees a total of 12 satellites being launched between now and 2020, when Galileo will be fully operational.

“You can say we wait until we find the solution, but that means if more clocks are failing then we are reducing the capability of Galileo," Woerner said. "If we launch, we will at least sustain if not increase the possibility of Galileo, but we may take the risk (of) a systematic problem."

Despite the broken clocks, the project to create a European-controlled version of America’s GPS is still functioning.  

“There is no failure of a satellite at the moment due to clocks,” said ESA spokeswoman Brigitte Kolmsee. “There is no satellite with three clock failures; all satellites have at least two working clocks.”

Its fleet of satellites carries two types of clocks, rubidium atomic frequency standards and passive hydrogen masers – supposed to be the most precise in the world. According to the ESA, “The stability of the rubidium clock is so good that it would lose only three seconds in one million years, while the passive hydrogen maser is even more stable and it would lose only one second in three million years.”

One of the biggest European projects since Airbus, Galileo has suffered several technical and budgetary setbacks, including the launch of two spacecraft into the wrong orbit in 2014, and is eight years behind schedule.