Space Western is a subgenre of science fiction which uses the themes and tropes of Westerns within science fiction stories. Subtle influences may include exploration of new, lawless frontiers, while more overt influences may feature literal cowboys in outer space who use ray guns and ride robotic horses. Although initially popular, a strong backlash against perceived hack writing caused the genre to become a more subtle influence until the 1980s, when it regained popularity. A further critical reappraisal occurred in the 1990s with Cowboy Bebop and again in the 2000s with Firefly.

A space Western may emphasize space exploration as “the final frontier”. These Western themes may be explicit, such as cowboys in outer space, or they can be a more subtle influence in space opera. Gene Roddenberry described Star Trek: The Original Series as a space Western. Firefly and its cinematic follow-up Serenity literalized the Western aspects of the genre popularized by Star Trek: it used frontier towns, horses, and the styling of classic John Ford Westerns. Worlds that have been terraformed may be depicted as presenting similar challenges as that of a frontier settlement in a classic Western. Six-shooters and horses may be replaced by ray guns and rockets.

Westerns influenced early science fiction pulp magazines. Writers would submit stories in both genres, and science fiction magazines sometimes mimicked Western cover art to showcase parallels. In the 1930s, C. L. Moorecreated one of the first space Western heroes, Northwest Smith. Buck Rogers and Flash Gordon were also early influences. After superhero comics declined in popularity in 1940s America, Western comics and horror comicsreplaced them. When horror comics became untenable with the Comics Code Authority in the mid-1950s, science fiction themes and space Westerns grew more popular. By the mid-1960s, classic Western films fell out of favor, and Revisionist Westerns supplanted them. Science fiction, such as Lost in SpaceStar Trek, presented a new frontier to be explored, and films like Westworld rejuvenated Westerns by updating them with science fiction themes.Peter Hyams, director of Outland, said that studio heads in the 1980s were unwilling to finance a Western, so he made a space Western instead. Space operas such as the Star Wars film series also took strong cues from Westerns; Boba Fett, Han Solo and the Mos Eisley Cantina in particular were based on Western themes. These science fiction films and television series offered the themes and morals that Westerns previously did.

This frontier view of the future is only one of many ways to look at space exploration, and not one embraced by all science fiction writers. The Turkey City Lexicon, a document produced by the Turkey City science fiction writers’ workshop, condemns the space Western as the “most pernicious” form of a pre-established background that avoids the necessity of creating a fresh world. Galaxy Science Fiction ran an advertisement on its back cover, “You’ll never see it in Galaxy”, which gave the beginnings of make-believe parallel Western and science fiction stories featuring a character named Bat Durston. Such scathing attacks on the subgenre, along with further attacks on space operas, caused a perception that all space Westerns were by definition hack writing and not “true” science fiction. Although the underlying themes remained influential, this bias persisted until the 1980s, when the release ofOutland and children’s cartoons, such as Bravestarr and The Adventures of the Galaxy Rangers, repopularized explicit themes of cowboys in space.

In the 1990s, anime series, such as Cowboy Bebop, Outlaw Star, and Trigun became prime examples of the genre. In the late 1990s and early 2000s, both Cowboy Bebop and Firefly won critical acclaim, further causing a critical reassessment of space Westerns. Michelle Onley Pirkle, in her book Science Fiction Film, Television, and Adaptation: Across the Screens, said that “Cowboy Bebop is taking a new take on genre, not by creating unique images and sounds, but by playing “freely” with, “remixing”, or adapting the images and sounds of other familiar genres in a dynamic way.” Games such as StarCraft and the Borderlands series have also popularized the space Western theme.