Characterization of an ionic liquid electrospray thruster with a porous ceramic emitter

TLDR

An ionic liquid electrospray thruster was developed for use on micro‑nano satellites and gravitational wave detectors. The thruster employs a porous ceramic emitter with seven strips that deliver ionic liquid by capillary action without a liquid‑supply device, forming multiple emission sites, and its beam is characterized using a time‑of‑flight mass spectrometer and retarding potential analysis. It produced a stable 350 μA beam in negative mode, but a corona limited positive‑mode current; operating in the pure‑ion regime, it delivered 67.1 μN thrust with specific impulses of 3952 s (positive) and 3117 s (negative).

Abstract

An ionic liquid (IL) electrospray thruster was developed for application in micro-nano satellites or gravitational wave detectors. The thruster employed a porous ceramic emitter with seven emitter strips located on its emission surface. Without any liquid-supply device, IL was delivered through porous media to emitter strips via capillary effect. Multiple emission sites then formed at the tip of each strip. A charged beam of up to 350 μA (with a current density of 540 μA cm−2) was stably produced in the negative mode. However, in the positive mode, a corona was observed which could prevent the thruster from emitting larger current. A time-of-flight mass spectrometer with significantly improved signal-to-noise ratio was built, which was used to obtain the mass distribution of the beam of the thruster. A retarding potential analysis was also performed. The test results showed that the thruster worked in the pure-ion regime, and delivered a maximum thrust of 67.1 μN with specific impulses of 3952 s and 3117 s in the positive and negative modes, respectively.