I can't speak for the rovers, but in my experience you start with the UTC time and the convert to a UT1 for space launches. We have to correct for the differenc

I can't speak for the rovers, but in my experience you start with the UTC time and the convert to a UT1 for space launches. We have to correct for the difference, which is called DUT1: https://en.wikipedia.org/wiki/DUT1 https://en.wikipedia.org/wiki/DUT1