Vaughan, much like Star Wars, is a science fiction/fantasy hybrid which does not take place in our Milky Way galaxy.
Various supplemental materials put out by Akira Toriyama, as well as things throughout the run of the manga/anime, suggest that at the very least it's an alternate universe or timeline. All it takes is time and effort to find the info. The heroes' home is "Earth" In Name Only.
All new pages should use the preloadable templates feature on the edit page to add the appropriate basic page markup.
Tyrian 2000 fleet mission manual#