User blog comment:Mrob27/The moat experiment/@comment-4829477-20120210141606/@comment-4501235-20120210201128

If you've found a spot where Astronauts spawn, try saving and reopening the game several times. Not only does this reset their aggressiveness, it also seems to reset the spawn. Meaning if the programming is for astronauts to spawn at that location, lunacraft seems to re-run that code when you re-open your moon.