Re: M.A.S.E.R/L.A.S.E.R pedantry
"I thought microwaves were photons; doesn't that make the M.A.S.E.R/L.A.S.E.R argument a little redundant?"
Yes, as far as physics is concerned, "light" refers to the entire electromagnetic spectrum, so masers are just subsets of lasers. Plus, it's worth bearing in mind that we also have IR, UV and x-ray lasers, and they're always just called lasers. Maser get their own name partly because they came first before being generalised to lasers, but probably mainly because they're the only sub-variant that doesn't sound really stupid.
As for the article itself, there's surprisingly little information given here. The BBC article is much more informative - http://www.bbc.co.uk/news/science-environment-38664225
In summary - there are three different failure modes identified. The three failures in the rubidium clocks all appear to be due to a short circuit and may be related to a test performed before they are launched. The hydrogen clocks have two failure modes, the most common one apparently being an issue with the clocks not starting back up if they're turned off for too long (it's implied that although there are four clocks on each satellite, they're not all running continuously and that this can be worked around by simply changing how long they're turned off for). Only 2/14 of the main operational satellites have been affected (all 3 rubidium failures and 1 hydrogen failure), while the other 5 hydrogen failures have been split between 3/4 of the early test satellites. Finally, the Indian sat-nav system uses the same clocks, but has not had any similar failures.
And to correct the article, which somehow cited the BBC article while missing out most of the information and getting half the rest wrong, the BBC did not note that one satellite has suffered two clock failures, it says that four of them have suffered two clock failures. This can be easily seen by a little simple arithmetic on the numbers above. Perhaps next time just linking to the competent article and leaving at that would be a better idea?