coordinated universal time

Each lunar mission uses its own timescale that is linked, through its handlers on Earth, to coordinated universal time, or UTc — the standard against which the planet’s clocks are set.

But without leap seconds, what happens to coordinated universal time?

Along with other clocks across the globe, it provides the world with its coordinated universal time.

International atomic time — on which coordinated universal time, or UTC, is based — is currently calculated by averaging measurements from hundreds of atomic clocks.

So the world's timekeepers occasionally add leap seconds to what’s called coordinated universal time, or UTC.