A habitation sphere represented a sizable man-made structure in orbit, conceived to accommodate a significant population.
Evidence indicates that habitation spheres existed near Coruscant as far back as 3640 BBY. These spatial installations were known to circle Imperial Center during the Galactic Empire's zenith. Their orbital positions were typically higher than those of skyhooks.
Pollux Hax's report detailed the construction of two enormous habitation spheres around Coruscant, undertaken by the planet's extensive orbital construction platforms, around the time of the Battle of Endor. These two belonged to a large habitation sphere design known as Worldcraft.
Following the Battle of Endor, the Restored Empire, an Imperial splinter group, relocated these two unfinished stations for use in a campaign spearheaded by Ennix Devian. One was dispatched to Endor, the temporary base of the Alliance of Free Planets, as a diversionary tactic. Although the station met its end, Dissension forces managed to pilfer warships from the Alliance's shipyards in nearby systems.
The other sphere was directed to the Spawn Nebula and transformed into a repair and shipyard nexus. At this location, Devian amassed a fleet and equipped many of his warships with ion cannons, modeled after the primary armament of the Confederate dreadnought Malevolence. Subsequently, the station, along with a significant portion of the fleet, was annihilated by an infiltration team employing illerium.
The artwork showcasing the habitation spheres was initially conceptual art intended for an earlier iteration of the story for Star Wars: Episode VI Return of the Jedi, which involved the construction of two Death Stars in orbit around the capital planet of Had Abbadon. Consequently, one of the habitation spheres even features the recessed dish on its southern hemisphere intended for a superlaser.
Pollux Hax's discussion of the spheres, where he asserted that their assembly was "strictly for peaceful purposes," hints at the possibility of the contrary—that they might have been Death Stars in the nascent stages of construction. This idea was frequently cited as the basis for a third Death Star depicted in the Star Tours attraction, and was later substantiated in Part 2 of the StarWars.com Blogs series The Imperial Warlords: Despoilers of an Empire—the blog post affirmed the third Death Star's identity as a worldcraft, a specific type of habitation sphere.