I rather like Michael Tsarion's explanation for why the "moon landings" and other space adventures were faked:

According to Michael Tsarion, there were some "Bad Guys" (BG) being chased across Our galaxy by some "Good Guys" (GG). The BG arrived in Our solar system, set up a decoy on Tiamat (the planet between Mars and Jupiter), then came to Earth and hunkered down.

The GG arrived, saw the decoy, checked for native sapient life, found none, and blew the planet up (explaining the asteroid belt). They were suspicious, though, and checked the other planets, somehow determining that the BG were here. And They found plenty of sapient life native to the planet. So... They put a barrier up around the globe above low earth orbit that We can't get through. They moved the moon into place to be a "guard tower" (explaining the many stories around the globe of a time when there was no moon, and the claims "the gods" put it there). Also explaining "The Watchers."

We can't get through that barrier and live...and They don't want Us to know.

But... Who knows what's going on? I just know, based on My observations, measurements, calculations, geometry, logic and reason, I give the idea We're on a globe the size They say a probability approaching 100%.