More on the European satellites clock problems

I had noted three days ago that something was happening with the clocks on board the new constellation of navigation satellites that Europe was putting in orbit. Spaceflight 101 has a bit more:

ESA studies multiple Atomic Clock Failures on Galileo Navigation Satellites
The European Space Agency is studying a potentially serious problem with the atomic clocks that drive Europe’s Galileo Navigation Satellites and have shown an alarming failure rate across the early phase of the satellite constellation.

European government officials decided to postpone the next Galileo satellite launch by three months from August to a tentative target of November to provide sufficient time for engineers to look into atomic-clock failures on orbiting satellites. ESA and industry specialists are now working to uncover multiple systemic issues with Galileo’s onboard systems that already caused ten clocks to stop operating on orbiting satellites.

What caught my eye in this article was this:

Particularly worrying is that both types of clocks are affected – six Hydrogen Masers and three of the Rubidium devices are currently out of commission. The issue is further complicated by the fact that clock failures occurred on two different satellite platforms, one built by Airbus and Thales Alenia as part of the In-Orbit Validation (IOV) satellite series and the other by OHB Systems that is the prime contractor for the operational Galileo satellites.

The idea that the same failure could occur on two completely different platforms is troubling. The clocks are single-sourced (a bad idea for anything as complex as this) but they seem to be well designed:

The common denominator between the different types of clocks and satellite buses is SpectraTime, a Swiss firm that provides both atomic clocks for the Galileo constellation. SpectraTime, ESA and the satellite manufacturers are currently in the process of working through an extensive fault tree, but work already revealed that the design of both clock types is sound and the fault is likely within an auxiliary piece of equipment that causes clocks to fail when operated in a certain way, possibly with several contributing factors.

At least we have our GPS still ticking along and the Russian Glonass is not bad either. A lot of recent receivers can use both seats of birds so navigation and timing are greatly improved for everyone.