To wit: they want to build a Lunar GPS/GNSS nav system, and this is the time-sync part of the nav system. Lunar time runs faster than Earth TAI atomic time by 1

To wit: they want to build a Lunar GPS/GNSS nav system, and this is the time-sync part of the nav system. Lunar time runs faster than Earth TAI atomic time by 1 millisecond every 2 weeks, 21 ms per year, or 1 second every 48 years.