The High-Power Electric Propulsion Lab (HPEPL) is engaged in work to characterize electric propulsion devices, plasma physics, non-invasive plasma diagnostics, and vacuum test facility effects on the performance of electric propulsion devices. Under Dr. Walker’s leadership, the group’s research activities involve both theoretical and experimental work in advanced spacecraft propulsion systems, diagnostics, plasma physics, helicon plasma sources, space debris mitigation, magnetoplasmadynamic thrusters, and pulsed inductive thrusters. Dr. Walker specifically has extensive design and testing experience with Hall thrusters and ion engines and has performed seminal work in Hall thruster clustering and vacuum chamber facility effects.  

Applications for the lab’s work include electric propulsion devices for future space applications that take advantage of advancements in plasma physics.  

Research Goals  

• Performance: Increasing the robustness and efficiency of high-power electric propulsion devices 
• Deployability: Identifying and understanding spacecraft integration issues that may prevent widespread use of electric propulsion systems 
• Longevity: Understanding the life-limiting factors of electric propulsion devices 
• Applicability: Identifying non-propulsion applications (e.g., space-plasma simulation and re-entry flow simulation) 

Activities  

• Theoretical and experimental research: Conducting field-leading investigations into myriad aspects of electric propulsion–related systems impacting space-based applications 
• Thruster design and testing: Performing seminal work involving Hall thrusters and ion engines, including thruster clustering and vacuum chamber facility effects 
• Vacuum chamber experiments: Leveraging two large vacuum test facilities (VTF-1 and VTF-2) to accommodate a diverse range of research experiments pertinent to the characterization of electric propulsion devices 
• Diagnostics: Employing a wide-range of plasma probe diagnostics and facility measurement techniques as well as rigorous probe calibration and check-out procedures to accurately define the uncertainty of each measurement 
• Consulting: Advising top-tier industry leaders and government agencies in the areas of electric propulsion system design, root cause on-orbit anomaly investigation, spacecraft integration, advanced propulsion technology evaluation, electric propulsion technology development roadmaps, vacuum technology, and the development and review of technical proposals 

Leadership 

• Director, High-Power Electric Propulsion Lab, Georgia Tech 
• Director, NASA’s Joint Advanced Propulsion Institute (JANUS) 
• Deputy Director, Space Rockets and Advanced Propulsion, American Institute of Aeronautics and Astronautics (AIAA)  
• Associate Fellow, American Institute of Aeronautics and Astronautics (AIAA) 
• Associate Editor, Journal of Spacecraft and Rockets 
• Chair, National Institute for Rocket Propulsion Systems Technology Solutions Committee 
• Chair (Former), AIAA Electric Propulsion Subcommittee for Technical Achievement Award
• Member, Technology, Innovation, and Engineering Committee, NASA Advisory Council

Dr. Walker has also served on the National Research Council Reusable Booster System Committee and the NASA International Space Station Electric Propulsion Testbed Study Committee.