Accurate timekeeping is critical infrastructure. So much so, that the US government operates many radio stations whose sole purpose is to provide current time a

Accurate timekeeping is critical infrastructure. So much so, that the US government operates many radio stations whose sole purpose is to provide current time announcements, reference clocks, and other timekeeping-related information. See [0]. Relatedly: surely you're not of the opinion that the various GPS constellations are not critical infrastructure? [0] <https://www.nist.gov/pml/time-and-frequency-division/time-services/time-signal-broadcast-stations https://www.nist.gov/pml/time-and-frequency-division/time-se...>