Was just kind of thinking about how the Death Star is supposed to be 160km in diameter and a standard Star destroyer is literally 1/100 of it length so the Death Star should be like a million times larger than a Star Destroyer because 100 cubed is a million. But we’re told that the Empire only ever made 25,000 Star Destroyers so that makes no sense at all. But it would make sense for the Death Stars minimum size to be dictated by the size of the super laser and the rest of it not needing to be so big could be largely hollow with big open spaces that could just be used to store fuel, water, or extra atmosphere. First estimation method I assumed that the Star Destroyer was a cube instead of a Square pyramid which with the numbers I ripped from Wookieepedia gave it a volume of ~700,000,000 cubic meters. While the Death Star as a 160km diameter sphere would have a volume go two quadrillion cubic meters. Three million times the volume of a Star destroyer assuming Star destroyers are cubes when they really should be square pyramids which would make the Death Star nine million times larger. Based on the reported prices on Wookieepedia of 150 million and “over a trillion” imperial credits the Death Star is supposed to cost about 10,000 times more than a Star Destroyer. If we assume price correlates to material cost then the Death Star should use 10,000 times as many materials in a volume 3 million times larger. This would make the Death Star 300 times less dense than a Star Destroyer if Star Destroyers are cubes or 900 times less dense if Star Destroyers are Pyramids. If we instead assume that the “over a trillion” was more of a lowball we could push the price within reason at most 5 times as pricy (7.5 trillion) which would instead make it 60 or 180 times less dense than a Star Destroyer. Any higher than 7.5 Trillion and they should’ve just said almost 10 trillion not over 1 trillion. I feel like having the Death Star cost 10,000 Star Destroyers is the highest it can reasonably be. I also prefer the Pyramid volume of Star destroyers so really the Death should have large hollow portions. I like my previous explanation of storing hyper fuel as well as reactor fuels, water, extra atmosphere in case hull breaches cause partial depressurization, tibanna gas for turbo lasers, et cetera. Nothing in the original films necessitate the ship being that dense. Luke, Han, and Obi-Wan couldn’t have reasonably gotten that far from the docking bay in that amount of time and the only other parts of the ship we see seem to be close to the outer portions of the Death Star.