Wired physics writer Rhett Allain goes about estimating the crew compliment of the Death Star from “Star Wars”… needless to say figuring out how many people could be aboard a vessel the size of a small moon isn’t that simple, so Allain started out by analysing the size of far smaller naval craft:

I went through the list of US Navel Wessels and tried to get one of each class. In order to calculate the volume, I had to make a couple of guesses. First, I had to guess the height of the ship. Wikipedia seems to list the draft (which would be the depth of the ship below water level – I think). So, I just kind of guessed at the height. Really, in my mind I pictured the ship as a rectangle. So, the height listed is my approximation of how tall the ship would be if it were squashed into a rectangular cube.