The thesis work was undertaken in collaboration with T4i-Technology for propulsion and innovation S.p.A. of Padova. The analysis of the electric propulsion background made it possible to identify the arcjet thruster as an excellent trade-off between the characteristics and performance of other devices. The high thrust-to-weight ratio, good specific impulse values, shorter implementation time of a collision avoidance maneuver for the readiness to reach a certain delta v compared to any other electric thruster are the strengths of this technology and the project is made even more promising by the choice of using a green propellant such as the water. The expected performances are evaluated by implementing a simplified analytical model that is suitable for this preliminary design which has been defined in the perspective of an IOD..