Lifetime Considerations for Electrospray Thrusters

Aerospace

卷:7

JohnK. Ziemer¹  RichardE. Wirz²  PeterL. Wright²  Anirudh Thuppul²  AdamL. Collins² 

[1] LISA Microthruster Technology Lead, NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA;

[2] Plasma & Space Propulsion Laboratory, UCLA Mechanical and Aerospace Engineering, 420 Westwood Plaza, Los Angeles, CA 90095, USA;

关键词: electrospray;    lifetime;    electric propulsion;    thrusters;    overspray;   

DOI  :  10.3390/aerospace7080108

来源: DOAJ

【 摘 要 】

Ionic liquid electrospray thrusters are capable of producing microNewton precision thrust at a high thrust–power ratio but have yet to demonstrate lifetimes that are suitable for most missions. Accumulation of propellant on the extractor and accelerator grids is thought to be the most significant life-limiting mechanism. In this study, we developed a life model to examine the effects of design features, operating conditions, and emission properties on the porous accelerator grid saturation time of a thruster operating in droplet emission mode. Characterizing a range of geometries and operating conditions revealed that modifying grid aperture radius and grid spacing by 3–7% can significantly improve thruster lifetime by 200–400%, though a need for explicit mass flux measurement was highlighted. Tolerance analysis showed that misalignment can result in 20–50% lifetime reduction. In addition, examining the impact of electron backstreaming showed that increasing aperture radius produces a significant increase in backstreaming current compared to changing grid spacing. A study of accelerator grid bias voltages revealed that applying a reasonably strong accelerator grid potential (in the order of a kV) can minimize backstreaming current to negligible levels for a range of geometries.

【 授权许可】

Unknown