Iron Voyager was a sea-going vessel on the planet Gethsemane. It was one of the few artifacts to survive the destruction of the planet.  The Aves Phoenix encountered Iron Voyager adrift in interplanetary space after the planet was destroyed. (Book 09 - Gethsemane

It drifted through space for several Million years before slipping into the gravity well of the moon that formed from the iron core of the rogue planet that destroyed Gethsemane.