Space Science fiction is one of the sub-genres of sci-fi adventure, which is usually determined by formal criteria: the action takes place in outer space and/or on other planets (in our solar system or beyond).
Space sci-fi can be roughly divided into several trends:
Space odyssey: the action takes place on a spaceship during a particular mission.
Planetary romance (planetary science fiction): this is a subgenre where the action is confined to one planet.
Space opera, where the action usually takes place in the distant future, there are several galactic empires that are hostile towards each other and, among the multitude of alien races, there are many humanoids who are almost identical to people.