Magnetically Shielded Miniature Hall Thruster: Flight Qualification, LIF, and Krypton Performance

Experimental and theoretical studies of magnetic shielding of Hall thrusters have shown significant enhancement of lifetime through reduced erosion of the thruster discharge channel. This enabling technology provides the capability for Hall thrusters to operate in deep space missions. A low power variant of a thruster with this technology - the Magnetically Shielded Miniature (MaSMi) Hall thruster - was developed at JPL to operate at relatively low powers of 200 - 1500 W with total efficiency as high as 60%. This thruster successfully passed flight qualification through JPL and was recently licensed to ExoTerra Resource for flight production (renamed Halo12), where additional flight qualification was instigated to extend its known capabilities. Under this program, the long duration wear test has been extended beyond the previous 7205 h duration and 1.55 MN-s total impulse for a total of 8187 h duration and 1.734 MN-s total impulse. Laser Induced Fluorescence measurements of the plasma shows the thruster operation is relatively invariant to off-nominal conditions, such as elevated background pressure, thruster temperature, and off-nominal magnetic field strength. Performance measurements of the thruster were conducted for krypton, which showed a familiar efficiency gap compared to xenon, however the performance was still as high as 51%.

针对霍尔推力器（Hall thruster）磁屏蔽的实验与理论研究表明，通过降低推力器放电通道的侵蚀损耗，可显著提升其服役寿命。该项赋能技术使得霍尔推力器能够胜任深空任务运行需求。采用该技术的低功率推力器变体——磁屏蔽微型（Magnetically Shielded Miniature，MaSMi）霍尔推力器——由喷气推进实验室（Jet Propulsion Laboratory，JPL）研发，可在200至1500瓦的较低功率区间运行，总效率最高可达60%。该推力器已顺利通过喷气推进实验室的飞行资质认证，近期被授权予艾克索泰拉资源公司（ExoTerra Resource）开展飞行级量产（该产品更名为Halo12），后者启动了额外的飞行资质认证工作以拓展其已知性能边界。在本项目框架下，长历时磨损试验的时长已从此前的7205小时、总冲量1.55兆牛秒拓展至8187小时、总冲量1.734兆牛秒。等离子体激光诱导荧光（Laser Induced Fluorescence，LIF）测量结果显示，该推力器的运行特性对各类非标称工况（如升高的背景压力、推力器温度以及非标称磁场强度）相对保持稳定。针对氪气的推力器性能测试结果表明，其与氙气工况存在普遍的效率差距，但仍可实现高达51%的性能效率。