Fairfield Plume Measurement and Analysis on the NASA-300M and NASA-300MS

NASA is developing a 10- to 15-kW Hall thruster system to support future NASA missions. This activity is funded under the Space Technology Mission Directorate Solar Electric Propulsion Technology Demonstration Mission project. As a part of the development process, the NASA-300M, a 20-kW Hall thruster, was modified to incorporate the magnetic shielding concept and named the NASA-300MS. This activity was undertaken to assess the viability of using the magnetic shielding concept on a high-power Hall thruster to greatly reduce discharge channel erosion. This paper reports on the study to characterize the far-field plumes of the NASA-300M and NASA-300MS. Diagnostics deployed included a polarlyswept Faraday probe, a Wien filter (ExB probe), a retarding potential analyzer, and a Langmuir probe. During the study, a new, more accurate, integration method for analyzing Wien filter probe data was implemented and effect of secondary electron emission on the Faraday probe data was treated. Comparison of the diagnostic results from the two thrusters showed that the magnetically shielded version performed with ~2 percent higher voltage utilization efficiency, ~2 percent lower plume divergence efficiency, and ~2 percent lower mass utilization efficiency compared to the baseline version. The net change in efficiency is within the aggregate measurement uncertainty so the overall performance is roughly equal for the two versions of the thruster. Anode efficiency calculated from thrust stand measurement corroborates this finding.

[1]  Nathan J. Strange,et al.  300-kW Solar Electric Propulsion System Configuration for Human Exploration of Near-Earth Asteroids , 2011 .

[2]  H. D. Hagstrum.  Metastable Ions of the Noble Gases , 1956 .

[3]  A. Gallimore,et al.  The Role of Magnetic Field Topography in Improving the Performance of High-Voltage Hall Thrusters , 2002 .

[4]  Hani Kamhawi,et al.  Langmuir Probe Measurements Within the Discharge Channel of the 20-kW NASA-300M and NASA-300MS Hall Thrusters , 2013 .

[5]  T. W. Haag.  Thrust stand for high‐power electric propulsion devices , 1991 .

[6]  V. Kim.  Main Physical Features and Processes Determining the Performance of Stationary Plasma Thrusters , 1998 .

[7]  Lee S. Mason,et al.  Benefits of Power and Propulsion Technology for a Piloted Electric Vehicle to an Asteroid , 2011 .

[8]  Alec D. Gallimore,et al.  Near-field Ion Current Density Measurements of a 6-kW Hall Thruster , 2009 .

[9]  Daniel L. Brown,et al.  Investigation of low discharge voltage Hall thruster characteristics and evaluation of loss mechanisms , 2009 .

[10]  Jeffrey M. Woytach,et al.  Feasibility of Large High-Powered Solar Electric Propulsion Vehicles: Issues and Solutions , 2013 .

[11]  Homer D. Hagstrum,et al.  AUGER EJECTION OF ELECTRONS FROM TUNGSTEN BY NOBLE GAS IONS , 1954 .

[12]  E. Choueiri.  Fundamental difference between the two Hall thruster variants , 2001 .

[13]  A. Savitzky,et al.  Smoothing and Differentiation of Data by Simplified Least Squares Procedures. , 1964 .

[14]  Richard R. Hofer,et al.  Mass and Cost Model for Selecting Thruster Size in Electric Propulsion Systems , 2013 .

[15]  I. Mikellides,et al.  Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase III: Comparison of Theory with Experiment , 2012 .

[16]  I. Mikellides,et al.  Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase II: Experiments , 2012 .

[17]  I. Mikellides,et al.  Magnetic Shielding of the Channel Walls in a Hall Plasma Accelerator , 2011 .

[18]  J. Linnell.  An evaluation of krypton propellant in Hall thrusters , 2007 .

[19]  Alec D. Gallimore,et al.  Method for analyzing E×B probe spectra from Hall thruster plumes , 2008 .

[20]  Homer D. Hagstrum,et al.  Auger Ejection of Electrons from Molybdenum by Noble Gas Ions , 1956 .

[21]  Alec D Gallimore,et al.  Evaluation of ion collection area in Faraday probes. , 2010, The Review of scientific instruments.

[22]  A. Gallimore,et al.  High-Specific Impulse Hall Thrusters, Part 2: Efficiency Analysis , 2006 .

[23]  Brian Eric Beal,et al.  Clustering of Hall effect thrusters for high -power electric propulsion applications. , 2004 .

[24]  P. Peterson,et al.  A High Specific Impulse Two-Stage Hall Thruster with Plasma Lens Focusing , 2001 .

[25]  Hani Kamhawi,et al.  Farfield Ion Current Density Measurements before and after the NASA HiVHAc EDU2 Vibration Test , 2012 .

[26]  Alec D. Gallimore,et al.  Evaluation of Facility Effects on Ion Migration in a Hall Thruster Plume , 2011 .

[27]  B. M. Reid,et al.  The Influence of Neutral Flow Rate in the Operation of Hall Thrusters. , 2009 .

[28]  Sang-Wook Kim,et al.  Experimental investigations of plasma parameters and species-dependent ion energy distribution in the plasma exhaust plume of a Hall thruster. , 1999 .

[29]  Alec D. Gallimore,et al.  Langmuir Probe Measurements in the Discharge Channel of a 6-kW Hall Thruster , 2008 .