An Analysis of Multiple Configurations of Next-Generation Cathodes in a Low Power Aall Thruster

The research presented here is an effort to integrate an existing hollow cathode design with a low power production Hall thruster in multiple geometries. Both externally- and internally-mounted cathodes were fabricated and operated in conjunction with a Busek BHT-1500 Hall thruster. Three insert materials were evaluated; Cerium Hexaboride (CeB6), Lanthanum Hexaboride (LaB6), and impregnated tungsten. The thruster was operated at a single operating condition for all testing. The operating specifications for the discharge were 300 V and 2.25 A, giving a total power of 675 W. The boride-based cathodes were tested in both geometries while the tungsten-based cathode was only tested in an external configuration. A Faraday probe was used to measure current density in the plume and a single Langmuir probe was used to characterize the plasma. The charge state of the ions was measured with an ExB probe. All assembly and testing occurred at the Air Force Institute of Technology's (AFIT) Space Propulsion Analysis and System Simulation (SPASS) lab facility. The thruster's performance with the externally-mounted boride-based cathodes installed demonstrated the highest levels of efficiency and performance. The thruster's performance with the tungsten-based cathode installed was slightly less than with the externally-mounted boride-based cathodes. The lowest thruster performance occurred with the internally-mounted cathodes installed. The primary loss mechanism observed was an increase in multiply-ionized propellant with the internally-mounted cathodes. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.