aka Girls on the Moon, aka Moon Dolls, aka Nature Girls ion the Moon, aka Nature on the Moon
How bad is it? Pretty bad, even by 1960's nudie standards.
Should you see it? If you've never seen a nudie, a Doris Wishman film - maybe on a slow night.
I saw this originally on a "Joe Bob Briggs Presents the Wold's Sleaziest Films" VHS and my main memory of it was a guy with some silver hair pasted down with greasy kid stuff and my thinking "that looks like bird poop." Astronauts travel to the moon, which looks just like the Coral Gables nudist colony in Florida and encounter a world of topless women. When they return, they have no proof of their discovery and one guy suddenly notices that his secretary looks like the queen of the moon, so he takes an interest in her. There's little effort at making anything reasonably scientific, nor of developing characters or plot. The silliest moment is perhaps when the guys communicate by radio, though sitting next to each other. It's slow. The only reason it exists is because it was made in that brief era when films made in nudist camps were considered "educational" and could thereby bypass the requirement that women couldn't be shown topless. I didn't know it was directed by Doris Wishman under a pseudonym for some time, though her trademarks are all there.