cool, like the yuuzhan vong in a sense a planet is one of these already, just a little less maneuverable than we would maybe prefer out of a ship, and inverts

cool, like the yuuzhan vong in a sense a planet is one of these already, just a little less maneuverable than we would maybe prefer out of a ship, and inverts the hard shell soft interior crustacean-ship idea for large ships maybe you could literally use a planet, e.g. swing a spare one out of the solar system in the direction you want to go... if rogue planets can hold down an atmosphere and stay geologically active [0] maybe you could have liquid water oceans and sea life and atlantean cities scattered around the seafloor drawing hydrothermal power plus you're hidden pretty well flying dark in interstellar space, maybe civilizations deem it prudent to leave their parent stars for dark forest concerns etc, maybe you could even harness earthquakes/vulcanism to (very slowly) manipulate the angular velocity vector enough to course-correct and navigate [0]: https://doi.org/10.1038%2F21811 https://doi.org/10.1038%2F21811