Based on the mathematical models of the operation of the space propulsion system components established in Chap.  2 and the Modelica programs for the startup, steady-state and shutdown processes of the components, the thruster simulation system for each type of thrust can be conveniently assembled. By inputting known parameters of the thruster, such as the gas cylinder and pressure-reducing valve structural parameters, propellant density, pipeline diameter and length, and thrust chamber structural parameters, into the simulation system, the response of a single thruster can be analyzed in terms of pipeline pressure, flow rate, combustion chamber pressure, temperature, component ratio, thrust and other parameters, on which basis in this book it discussed the effects of the gas cylinder pressure, pressure-reducing valve characteristics, filling and shutdown characteristics, thruster response time, the effects of the combustion chamber volume and the inner diameter of the nozzle throat.