I'll give this a try as well. The density of misconceptions in your question is high, but I think I've identified the base misconception: you don't fully understand inertia.You seem to be under the impression that "the astronaut command" (or computer command) to use the RCS system consists of holding down a firing button or trigger or some sort with the button being released precisely at the moment the spacecraft has reached the final desired orientation. And then some mystery action you are inquiring about causes the craft to stop.This is not how it works. In a simple example the RCS thrusters are pulsed once at start of movement. While the craft is rotating the thrusters are off. Then at the end of the planned rotation (usually controlled by a computer) the thrusters are pulsed again to stop the craft. It is true that inertial sensors and guidance hardware predict exactly the RCS pulse needed to come to a clean stop, among many other things.