High-power Hall Thrusters

The X3 operating at 30 kW in the LVTF.

project personnel
Leanne Su

principal investigator
Benjamin Jorns

previous personnel
Sarah Cusson, Scott Hall, Michael McDonald, Daniel Brown, Bryan Reid, Jesse Linnell, Mitchell Walker, Peter Peterson, Richard Hofer, James Haas, Frank Gulczinski

project sponsors

associated thrusters
H6, X3, H9, N30


The exact power level that qualifies as “high-power” in Hall thrusters is a shifting target. In the 1990s anything over a kilowatt would have been considered high power, yet with the advent of thrusters like the 50-kW NASA 457M and more recently nested thrusters like the X2, the bar has shifted and now it would be fair to say that “high-power” begins in the 5-10 kW range, if not higher. This increase in electrical power is largely driven by a decrease in the cost of onboard electrical power for spacecraft and the ever-present desire for increased thrust, which requires an increase in mass flow rate and thus electrical current as each propellant atom is ionized and ejected. In contrast the voltage range of Hall thrusters has remained surprisingly steady over the past few decades, residing generally in the 300 V range up until the early 2000s, when research at PEPL outlined improved magnetic circuit designs for efficient operation at higher voltages (see ref. 2). While Hall thrusters are still often run in the low hundreds of volts, operation at high efficiency up to 1000 V has been demonstrated at PEPL, approaching a domain traditionally reserved for gridded ion thrusters.

PEPL has designed, built, and extensively researched a family of 5-6 kW single channel thrusters, beginning with the 5-kW class P5 (co-developed with the AFRL, see ref. 1), followed by the 5-kW class NASA 173Mv1 and v2 (co-developed with NASA Glenn, see ref. 2), and more recently with a 6-kW laboratory model Hall thruster (co-developed with the AFRL and NASA JPL, see ref. 3). These thrusters have demonstrated improvements in magnetic field design and anode flow uniformity (see ref. 4) that push anode efficiencies up to nearly 70%. Leveraging these results and new design concepts like nesting and magnetic shielding, PEPL has recently designed and characterized higher-power thrusters: the two-channel X2 (10-kW class), the three-channel X3 (100-kW class), and the magnetically-shielded H9 (9 kW).

In addition to the above, PEPL is investigating alternative Hall thruster propellants. Krypton offers a cheaper, lower-thrust and higher-Isp alternative to xenon as a Hall thruster propellant. Historically, krypton performance has been limited by mass utilization efficiency, causing a large gap between krypton and xenon efficiencies. PEPL is continuing investigation into the causes of this difference, as well as how magnetic shielding may affect it.

Selected Publications

  • Development and Characterization of High-Efficiency, High-Specific Impulse Xenon Hall Thrusters

    Hofer, R. R

    University of Michigan, Ph.D. Dissertation, 2004

  • Design of a 6-kW Hall Thruster for High Thrust/Power Investigation

    Haas, J. M., Hofer, R. R., Brown, D. L., Reid, B. M., Gallimore, A. D.

    54th JANNAF Propulsion Meeting, Denver, CO, May 14-17, 2007

  • The Combination of Two Concentric Discharge Channels into a Nested Hall-Effect Thruster

    Liang, R.

    University of Michigan, Ph.D. Dissertation, 2013

  • Implementation and Initial Validation of a 100-kW Class Nested-channel Hall Thruster

    Hall, S., Florenz, R., Gallimore, A., Kamhawi, H., Brown, D., Polk, J., Goebel, D., Hofer, R.

    50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cleveland, OH, AIAA 2014-3815, July 28-30, 2014

  • The X3 100-kW Class Nested-Channel Hall Thruster: Motivation, Implementation, and Initial Performance

    Florenz, R

    University of Michigan, Ph.D. Dissertation, 2014

  • 30-kW Performance of a 100-kW Class Nested-Channel Hall Thruster

    Hall, S.J., Cusson, S.E., and Gallimore, A.D

    34th International Electric Propulsion Conference, Kobe, Japan, IEPC 2015-125, July 6-10, 2015

  • 30-kW Constant-Current-Density Performance of a 100-kW-class Nested Hall Thruster

    Hall, S.J., Cusson, S.E., and Gallimore, A.D

    MIPSE Graduate Symposium, Ann Arbor, MI, Poster, October 7, 2015

  • Control of the Electron Energy Distribution Function (EEDF) in a Hall Thruster Plasma

    Trent, K.

    University of Michigan, Ph.D. Dissertation, 2016

  • Characterization of a 100-kW Class Nested-Channel Hall Thruster

    Hall, Scott J.

    University of Michigan, Ph.D. Dissertation, 2017

  • Update on the Nested Hall Thruster Subsystem for the NextSTEP XR-100 Program

    Jorns, B.A., Gallimore, A.D., Hall, S.J., Peterson, P.Y., Gilland, J.E., Goebel, D.M., Hofer, R.R., and Mikellides, I.

    54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, AIAA-2018-4418, July 9-11, 2018

  • Development of a 30-kW Class Magnetically Shielded Nested Hall Thruster

    Cusson, S.E., Hofer, R.R., Goebel, D.M., Georgin, M.P., Vazsonyi, A.R., Jorns, B.A., and Gallimore, A.D., and Boyd, I.D.

    36th International Electric Propulsion Conference, Vienna, Austria, IEPC-2019-266, 2019

  • Impact of Neutral Density on the Operation of High-Power Magnetically Shielded Hall Thrusters

    Cusson, Sarah E.

    University of Michigan, Ph.D. Dissertation, 2019

  • Non-invasive in situ measurement of the near-wall ion kinetic energy in a magnetically shielded Hall thruster

    Cusson, Sarah E.

    Plasma Sources Science and Technology, Vol. 28 No. 10, 21 October 2019

  • Investigation of the Hall Thruster Breathing Mode

    Dale, Ethan T.

    University of Michigan, Ph.D. Dissertation, 2020

  • Operation of a High-Power Nested Hall Thruster with Reduced Cathode Flow Fraction

    Hall, Scott; Jorns, Benjamin; Gallimore, Alec

    University of Michigan,, July 12, 2020

  • Future Directions for Electric Propulsion Research

    Dale, Ethan; Jorns, Benjamin; Gallimore, Alec

    ,, August 17, 2020

  • Performance of a 9-kW Magnetically-Shielded Hall Thruster with Krypton

    Leanne L. Su , Alexander R. Vazsonyi and Benjamin Jorns

    VIRTUAL,, August 17, 2020

  • Performance at high current densities of a magnetically-shielded Hall thruster

    Leanne L. Su and Benjamin A. Jorns

    AIAA Propulsion and Energy 2021 Forum,, August 2021

  • Performance Comparison of a 9-kW Magnetically-Shielded Hall Thruster Operating on Xenon and Krypton

    Leanne L. Su and Benjamin A. Jorns

    Journal of Applied Physics,, October 7, 2021