Fabrication of Electrospray Thrusters with a High-Density Emitter Array Utilizing Minimal-Fab System

Using a fabrication technology of field emitter arrays (FEAs), we have fabricated a high-density emitter array with 5-10 \mu m pitch as ion sources to improve the thrust density of electrospray thrusters. The emitter array is made on a Si wafer and consists of double Nb electrodes with sub-\mu m apertures, where ionic liquid as the propellant is expected to be extracted by applying voltage to the electrodes. This array can realize the emitter density of up to four million/cm2, which is four orders of magnitude higher than that of conventional electrospray thrusters.