The Pirate Homeworld is a planet visited by Samus Aran in Metroid Prime 3: Corruption. As the name states, this planet is the centre of operations for the Space Pirates. Unused text in the Japanese version of the game suggests that the planet's real name is Urtraghus and is not actually the Pirates' planet of origin. Throughout their history, the Pirates have claimed indisputable right of control over the planets they have conquered, going so far as to claim each one as a "homeworld" and developing new Pirate breeds that are "native" to each conquered planet. The true origin place of the Space Pirates remains a mystery and Urtraghus is merely one of several Pirate "booty" planets.
The Pirate Homeworld's environment is largely toxic. Storms of harmful acid rain are a regular occurrence and the Pirates have shielded all of their planetside facilities to protect themselves and their structures and technology. They also rely heavily on mass transit systems as walking on foot outdoors is extremely hazardous. In all likelihood, the Pirates themselves were responsible for making the environment as it is with large-scale pollution generated as a by-product of the continual build-up of their war machine.
The Urtraghian ecosystem was further damaged following the impact of a Leviathan Seed that spread Phazon corruption across most of the planet. When Dark Samus began seeding planets with Phazon, Urtraghus was the first planet she targeted. As such, the Pirate Homeworld was in a more advanced stage of corruption than the other planets that Samus Aran visited over the course of Metroid Prime 3. Large, luminescent blue stalks indicative of Phazon could be seen on the planet's surface from sub-orbital heights. These areas of corruption likely deteriorated after the destruction of Phaaze, which resulted in the dissolution of Phazon galaxy-wide.