Steady as she goes keep on with the same careful progress; in nautical parlance, steady is the instruction to the helmsman to keep the ship on the same course.
steady state an unvarying condition in a physical process, especially as in the theory that the universe is eternal and maintained by constant creation of matter. The steady state theory postulates that the universe maintains a constant average density, with more matter continuously created to fill the void left by galaxies that are receding from one another. The theory has now largely been abandoned in favour of the big bang theory and an evolving universe.
See also full cup, steady hand, slow and steady wins the race.