Not all Space Marine Chapters have a single homeworld some chapters such as the Imperial Fists, Black Templars and Blood Ravens take their aspirants from several different worlds.
Many Astartes homeworlds are Feral Worlds, which provide the best warriors. Chapter Planets are exempt from normal Imperial Tithes. The commander of the chapter is often also the traditional ruler of the chapter planet, in which case the Chapter Master also holds the rank of Planetary Governor.
Astartes homeworlds may be Imperial planets, while some are not planets at all, but take the form of orbiting spacecraft, deserted moons and asteroids. A 'Chapter planet' is an Astartes world which is both governed by the chapter and which serves as the base for their fortress-monastery.
