I watched the beginning of Mission Stardust twice, I will say, but the first time was a mix of drunk and tired and I hardly remembered jack shit. This is of course, since it's the only way to get me to write, going back to the Sci Fi Invasion boxset. I write this down because later when I try to accumulate all these, I'll just search for that word and that'll help me sort them out.
Mission Stardust is your very average by-the-books alien sci fi movie, with a stiff astronaut and a would-be strong female character. It felt Corman-esque in some ways, though IMDb doesn't mention him.
Slab of beefcake Perry Rhodan and his couple of other astronauts are on the moon, and they discover that a alien race has landed there. They are led by beautiful and cunning Thora. Their race is on the brink of extinction due to lack of genetic material, and thus Perry thinks he can probably bone a hot alien girl. Thora is typically catty about being pursued in this way, and remarks constantly about how much better than him she is. That might be kinda cool in bed, now that I think about it.
There is a long sequence where all the aliens and astronauts some to Earth, and the aliens demonstrate their power in an almost slapstick sequence of events. There is a military unit (apparently the military has all of 8 guys in it) that interacts with the aliens a few times, as the aliens demonstrate their invisible force wall and then later their anti gravity gun thing.
In short, this movie was pretty dull and low-level entertainment, but it might provide a chuckle or maybe some vague sort of entertainment if you're high as a kite. I don't wanna give it too much or too little credit, suffice to say it's extremely average, lets leave it at that.