The following thesis work focuses on the design of an evaporator for a space engine; in particular, fluidics analyses and numerical simulations that drive the design process of this component are reported. The evaporator is part of a new cold gas propulsion system developed by the company T4i. The new engine takes advantage of the gas expansion in the nozzle to create thrust, but the propellant is stored in liquid state in the satellite. A specially designed evaporator is required to obtain the propulsive fluid in the gaseous phase and in order to use fluid for propulsion. The evaporator’s task is to ensure at any time and in any operating condition the complete vaporization of the propellant.