Analysis and Experimental Verification of Micro-Newton Level InFEEP Thruster Emission Models

Abstract In space gravitational wave detection missions, microthrusters serve as actuators for satellite drag-free control, requiring a thrust range of 0.1 to several tens of μN and a thrust resolution better than 0.1 μN. Due to its high resolution, Field Emission Electric Propulsion (FEEP) is considered promising for this application. This paper analyzes the emission model of a single-needle In-FEEP thruster and develops a prototype based on it. Emission voltage and current were measured to determine key parameters such as the ionization coefficient and flow impedance, with charge-to-mass ratio and current corrections validated through finite element analysis. The thrust is evaluated by the corrected model and the direct thrust measurement system. Results show that accounting for ionization and flow impedance effects, at emission voltages from 4 kV to 6 kV, the In-FEEP thruster generates thrust in the range of 1.33 μN to 4.58 μN, the deviation between measured and simulated, with calculated thrust remains within 0.5 μN. This offers a reliable theoretical basis for the design of multi-needle thrusters for space gravitational wave detection.