The document discusses audience expectations for science fiction based on historical context and how those expectations guide the look, story, and budget of sci-fi works. It then analyzes how sci-fi can provide critical dystopias by questioning power structures and maintaining hope. Invasions in sci-fi disrupt society but relationships, systems, and morals were already vulnerable. Invasions separate people into those who can change and those who give in to authority. There is no single fixed ideology among different invasion narratives due to their origins in authors and historical context.