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Characterization of Propellant Flow and Bias Required to Initiate an Arc Discharge in a Heaterless Hollow CathodeHeaterless hollow cathodes provide an opportunity to reduce complexity and improve reliability in electric propulsion systems. While removal of the heater has little effect on steady-state operation of a hollow cathode, it has a considerable effect on the ignition process. To successfully integrate a heaterless hollow cathode into a spaceflight electric propulsion system, it will be necessary to establish definitive requirements for the propellant feed and electrical subsystems so that ignition of a plasma discharge can be achieved reliably. The aim of this research was to form a better understanding of these requirements by performing an investigation of the propellant flow and voltage conditions required for the ignition of a plasma arc discharge. This aim was achieved by performing discharge initiation experiments using both a specially designed experimental apparatus and a functional heaterless hollow cathode assembly. It was demonstrated that there is a distinct difference in the voltage required to initiate a plasma discharge between two common electric propulsion propellants, xenon and krypton, which suggests that the developmental testing of heaterless hollow cathodes needs to be performed with the appropriate propellant gas species. Heaterless hollow cathode ignition experiments showed that the keeper orifice diameter has a strong effect on the voltage required to ignite a plasma discharge at a given propellant mass flow rate, while the effect of keeper-cathode separation distance was only strong at flow rates below 25 sccm (Xe).
Document ID
20190029290
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Ham, Ryan K.
(Colorado State Univ. Fort Collins, CO, United States)
Williams, John D.
(Colorado State Univ. Fort Collins, CO, United States)
Hall, Scott J.
(Vantage Partners, LLC Brook Park, OH, United States)
Benavides, Gabriel F.
(NASA Glenn Research Center Cleveland, OH, United States)
Verhey, Timothy R.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 22, 2019
Publication Date
August 19, 2019
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
GRC-E-DAA-TN70748
Meeting Information
Meeting: AIAA Joint Propulsion Conference 2019
Location: Indianapolis, IN
Country: United States
Start Date: August 19, 2019
End Date: August 22, 2019
Sponsors: American Institute of Aeronautics and Astronautics (AIAA)
Funding Number(s)
CONTRACT_GRANT: NNC12BA01B
WBS: 920121.01.04.01
CONTRACT_GRANT: See Comments
CONTRACT_GRANT: 80NSSC18K1156
Distribution Limits
Public
Copyright
Public Use Permitted.
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