How do you get the death star in empire at war?

I'm not sure about the story mode (i don't play it much), but i know that you can get it in galactic conquest by leveling up and building it at a level five space station. not sure if there is a specific planet, but i usually build it at kuat, to use the Star Wars novels' famous Kuat Drive Yards.

in empire at war, it is about ten or fifteen thousand credits. in forces of corruption, death star 2 is about 20 thousand credits.