Space agencies and private companies around the world have been scheduling their own lunar missions over the next few years, and that could be quite complicated to coordinate when they all use different time zones. During a meeting at the European Space Agency's ESTEC technology center in the Netherlands last year, space organizations discussed the "importance and urgency of defining a common lunar reference time."
In a new announcement, ESA navigation system engineer Pietro Giordano said a "joint international effort is now being launched towards achieving this." There are a few challenges: They will have to decide whether to keep lunar time synchronized with Earth's or not because clocks on the Moon run faster based on the satellite's position. Each day on the Moon is, in Earth terms, 29.5 days long.
– Mat Smith