There is no dark side of the moon. It's a misconception. The moon rotates just like the earth does, but it takes nearly a month to rotate once. It's in nearly perfect sync with the earth, which is why we only ever see the one side. But when it's a 'new moon ', aka fully dark to us, the other side is in full sun. You're seeing the moon day happen every month with the phases of the moon. So any moon base is gonna be dark two weeks a month.