Performance and Mission Capability Analysis of Field Emission Thrusters for Smallsats with Alternative Propellants

The rapid growth of small satellite missions, such as monolithic spacecraft, formation flying, and mega constellations, requires the utilization of compact, efficient, and robust electric propulsion technologies. Field emission thrusters exhibiting low thrust levels (????N - mN) and high precision, making them suitable for precise orbit management, drag compensation, and controlled end-of-life deorbiting. Its operation relies on field evaporation or ionization of the onboard propellant, <br> making thruster performance highly reliant on the propellant characteristics and selection. This study utilized a physics-based analytical model to estimate thruster figures of merit, including thrust, specific impulse, and propellant efficiency, taking into account propellant properties that impact field ionization. The impact of operational parameters, notably emitter voltage and current, is investigated in order to establish performance maps relating propellant characteristics to thruster figures of merit. Furthermore, the effects of emitter voltages of 2 to 12 kV and currents ranging from sub-μA to mA <br> are evaluated, corresponding with actual operating conditions and a total power budget of less than 60 W for smallsat platforms. The first-order orbital analyses for 3U and 6U CubeSat platforms reveal that FEEP thrusters with alternative propellants can support a variety of orbital mission scenarios.