The moon doesn't spin relative to earth so if you can see the earth in the sky, it will always be in the sky. If you watch the phases of the moon, you can easil

The moon doesn't spin relative to earth so if you can see the earth in the sky, it will always be in the sky. If you watch the phases of the moon, you can easily see that the darkness is just covering the same face that we always see. A moon base would always have line of sight to earth but would be in darkness half the time. Great for comms, not as great for solar power.