A Moonship is a mix between a small celestial body and a large space ship or station. They can actually get as large as some small planets but they're still called Moonships. Typically a moon is used as the main structure. It is strategically mined out and reinforced. What separates a Moonship from a particularly large moon base are the massive engines. While a Moonship spends most of its time in orbit around a sun or planet it is capable of breaking orbits to navigate freely or change where it is orbiting.