Oh, and Menow, when you said, "astronauts have seen all sides of the Moon" I took you to be talking of ones on the space station or shuttle.
Of course, orbiting the Moon itself, they would have seen the dark side. The closer and higher you get to a round object, the more you see of a hidden side. Of course, to see a cube's Dark Side, you have to go above the horizon of that side completely to even get a glimpse.
So astronauts, orbiting the Moon... hmm... if they were to orient their craft so that they could always see, say, Orion, out of a certain window, is the craft rotating?
I meant in 1969, when supposedly they went around the Moon.
But anyway, the point is, in this journey, they would have transited behind the Dark Side, from our view. [
link to www.makingthemodernworld.org.uk]