Genetic Algorithm for Ion Thruster Grid Design

Summary form only given. A genetic algorithm was used to optimize ion thruster grid sets with regard to maximizing impulse per unit area, essentially equivalent to maximizing propellant throughput capability per unit area. Ion thrusters, while currently used for satellite station-keeping, are also valuable for performing deep space missions, such as NASA´s Dawn mission, as a result of their high efficiency. During ambitious deep space missions, the ion thruster grids must be able to operate over the course of several years. Numerical simulation of grid erosion and prediction of grid lifetime become increasingly important as the costs and time requirements of experimental thruster qualification increase. The genetic algorithm presented herein made use of the ffx ion optics simulation code for grid lifetime predictions. Grid sets were optimized for many combinations of net accelerating voltage and current density, and grid feature recommendations are made concerning how future missions can be met.