Western Sci-Fi has elements of science fiction in a Western setting. It is the inverse of the Space Western. A science fiction Western occurs in the past, or in a world resembling the past (Westworld), in which modern or future technology exists. This sub-genre often overlaps with Steampunk.
SPACE WESTERN transposes themes of American Western books and film (e.g., cowboys) to a backdrop of futuristic space frontiers; it is the complement of the science fiction Western. A similar sub-genre, FRONTIER SCI-FI centers on stories of people conquering new frontiers, leaving our world to colonize a preferable one. Similar to hardscrabble miners, crafty independent spacemen ply the asteroid belt in search of resources to send back to civilization.