Space opera is a subgenre of science fiction that typically features adventurous heroes, epic conflicts, and romanticized views of space exploration and interstellar politics. In my opinion, there is not a clear delineation between where hardcore science fiction ends and space opera begins. However, once you become familiar with the subgenre, you know it when you encounter it. My own novella series, “Alexandra Forever 2291”, has strong space opera leanings, but there are elements of hard science fiction as well.
The number of subgenres in space opera is not clearly defined, as the classification can be subjective and is constantly evolving. As with the distinction between sci-fi and space opera, the genre lines within space opera are fuzzy. (“Alexandra Forever 2291” has elements of a few.) Caveat out of the way, below are six recognized subgenres within space opera.
Military space opera focuses on military conflicts and space battles, often featuring detailed descriptions of futuristic technology and tactics.
Space western has callouts to classical westerns, typically featuring lone heroes and outlaws, frontier settings, and shootouts in space.
Planetary romance features romanticized adventures on exotic alien worlds, often with a focus on exploring new cultures and encountering strange creatures.
Space opera comedy takes a more lighthearted approach to space opera, often featuring comedic characters and situations.
Space opera noir blends elements of film noir with space opera, typically featuring gritty, dystopian settings and morally ambiguous characters.
Space opera horror injects horror into space opera, often featuring terrifying monsters and supernatural phenomena in space.