A gridded ion thruster is a form of electric propulsion that is being rapidly developed and implemented in commercial and scientific spacecraft. This is in part due to having increased fuel efficiency, thus offering a reduced spacecraft mass. ECR is the phenomenon whereby electrons gain energy from microwave radiation in the presence of a specific magnetic field strength, and is used to ionise the propellant. Plasma generation using ECR instead of a hollow cathode can increase the lifetime and reliability of the thruster. Thrust is generated by accelerating ions to high speeds through a strong electric field created by a set of grids. These grids have complex shapes and the time and costs for manufacturing them can be reduced via additive manufacturing. The aim of this project was to design and manufacture an ECR gridded ion thruster and determine the feasibility of an additively manufactured gridded ion thruster. The design process for the thruster and neutralizer involved using COMSOL multi-physics software to optimize the grids, magnetic field and antenna. Analysing the additively manufactured grids under the Alicona Microscope and further simulation of the measured deviations showed that the performance was not affected, thereby proving the feasibility of additive manufacturing of the thruster grids. The magnetic field simulations were validated successfully by visualising the magnetic field lines using iron filings. This project is the first ever European additively manufactured ion thruster and it paves the way for future research in the fields of ECR thrusters and the use of 3D printing in manufacturing.