There are a few fundamental first principles for future exoatmospheric spacecraft design. For starters, for any pressure vessel, be it a human habitat or a propellant tank, a sphere is the ideal shape based on a mass per volume ratio. The second best choice, based on considerations such as launchability or (artificial?) gravity, are cylinders. After that, it's up to flat surface panels, either for heat rejection or for solar power generation. And if there are any propulsion units, their thrust vector with any forseeable technology better be aligned with the center of gravity of the craft - I'm looking at you, Enterprise...