User blog comment:OrigamiDragons/This is for All You Guys Who Like Experimenting on Astronauts/@comment-5236436-20120729050902

This seems to correlate with my findings. Have you looked around for astronaut lairs? I've found that placing turrets around my bases tend to make astronauts not spawn no matter how much polymer I place in my base and if I place too many polymers I can't even leave my base. Your polymer theory would explain why if theres more than one lair in a superblock the superblocks in the area turn into an astronaut warzone. I'll start a test right now, if only to enhance my research bases.