Space warfare or space combat was the use of armed starships and other spacecraft for the purposes of military actions across star systems and the galaxy. Along with ground warfare and starfighter combat, by 0 BBY space warfare was one of three most significant branches of warfighting. Evolving from water navy engagements and in turn the earliest orbital battles, space warfare became a high technology affair that often defined the outcome of the galaxy’s most important conflicts.

The Galactic Civil War of 2 BBY–19 ABY cemented the role of the Star Destroyer as the central warship of navies. Under Emperor Palpatine, the Planetary Security Forces were nationalized and merged into the Sector Groups, massive concentrations of fleet power at the sector level. Distrusting local loyalties, these fleets were rapidly filled with new ships loyal to Imperial Center (decommissioned PSF equipment and ships would later become a major source of resources for the Rebellion)^[1] The Imperial Navy ultimately expanded to become the largest military starfleet the galaxy had ever seen, peaking at 25,000 Star Destroyers and millions more smaller ships.