They don't need any meridians. The entire place will be one zone. The time will be the same everywhere. The problem is that the time there will move very sligh

They don't need any meridians. The entire place will be one zone. The time will be the same everywhere. The problem is that the time there will move very slightly differently than here on earth, because of the lower gravity, to the tune of 60 ms per day. That's almost a second every two weeks. So the question isn't "what time do we set the clocks to?" but "what time will it be an hour from now?" Have a leap-second every few weeks?