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Prof. Mitchell Walker

Prof. Mitchell Walker

Laboratory Director

Graduate Students

David Gomez

David Gomez

Graduate Student

David Gomez received a B.S. in Aerospace Engineering from Georgia Institute of Technology with highest honors in May 2018 and joined HPEPL as a graduate student in August 2018. David has been responsible for many facility upgrades to HPEPL’s vacuum testing facilities, most notably the development of the mass flow control and calibration system for Vacuum Test Facility – 2 (VTF-2). As an electric propulsion intern at NASA’s Jet Propulsion Laboratory, he designed brand new software to operate the HERMeS thruster and provide simultaneous data acquisition. His primary interests are in physics, electric propulsion manufacturability, and facility automation. David is very excited about the prospects of human exploration of the solar system and hopes to be a part of the generation that takes us there.

Sara Miller

Sara Miller

Graduate Student

Sara Miller received a B.S. in Aerospace Engineering with high honors from Georgia Tech in December 2017 and joined HPEPL as a graduate student in August 2018. As an undergraduate research assistant in HPEPL, Sara supported test operations for a Hall thruster as well as thermal vacuum chamber cryogenic system diagnostic efforts. As a Pathways Intern (co-op) in the Electric Propulsion Systems branch at the Glenn Research Center, she supported ion plume diagnostics and testing of NASA’s Evolutionary Xenon Thruster – Commercial (NEXT-C). Sara believes that electric propulsion is on the critical path to expanding our knowledge of the universe via deep space exploration. Her primary research interests lie in plasma-surface interactions and the development of high thrust-to-power ratio devices.

Nicholas Branch

Nicholas Branch

Graduate Research Assistant

Nicholas Branch received a B.S. in Aerospace Engineering from Georgia Tech with highest honors in December 2017 and joined HPEPL as a graduate student in January 2018. As an undergraduate, Nicholas led several efforts for the development of electrical and mechanical ground support equipment for Georgia Tech’s Prox-1 satellite. As an undergraduate in HPEPL, he designed and created an ion beam dump to protect against sputter and built new propellant feed systems for an arcjet test system, while also assisting in the firing, operation, and data collection of several ion thrusters. Nicholas spent time designing and overseeing the manufacture electrodes for a novel implementation of a magnetohydrodynamic generator. At NASA Marshall Space Flight Center, Nicholas developed software to visually extract mode shapes and frequencies from videos to reduce the complexity of modal testing for large structures such as SLS. Nicholas spent a summer working the SpaceX Dragon 2 Ground Operations team, developing tooling and infrastructure to prepare for the return of astronauts to space from U.S. soil. Nicholas believes advanced propulsion methods will play a key role in the return of manned spaceflight, and his interests lie in ion propulsion and plasma-material interactions.

Nathan Brown

Nathan Brown

NSF Fellow

Nathan holds B.S. and M.S. degrees in Aerospace Engineering from Georgia Tech. His research interests include Hall thruster facility effects, plasma-material interactions, and non-invasive plasma diagnostics. 

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Jean Luis Suazo Betancourt

Jean Luis earned his B.S in Aerospace Engineering with honors from the University of Maryland, College Park in May 2017 before joining HPEPL as a graduate student in August 2017. Jean Luis has research experience with analytical models. He helped develop algorithms and mathematical models whose designs varied from predicting the performance of prototype high-efficiency heat engines to measuring unsteady thrust from Valveless Pulse-jets. Jean Luis is currently working on qualification testing for industry clients as well as developing the skills necessary to earn his doctorate in electric propulsion and make a lasting and meaningful contribution to the field. He is interested in plasma-material interactions, thermal modeling and management, and high thrust-to-power Hall thrusters -- particularly the control scenarios and algorithms.

David Jovel

David Jovel

GEM & Aerospace Corporation Fellow

David began his aerospace engineering career as an undergraduate student at the University of Texas at Austin. While there, David participated in various student-led CubeSat development projects and completed two internships at NASA Goddard Space Flight Center. David earned a B.S. in Aerospace Engineering in 2011 and since then has made many contributions within the space industry through companies like Orbital ATK, Intelsat, and the Aerospace Corporation. He is determined in obtaining his doctorate in electric propulsion with a focus on the thermal management of high-power electric propulsion devices. David strongly believes in the equity of public education and mentoring the next generation of engineers, especially the youth from underrepresented communities in STEM. Most recently, David has helped mentor the H.D. Cooke Elementary’s robotics team in Washington D.C.


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Connie Liu

Connie Liu

NSF Fellow

Connie Liu received a B.S. in Aeronautical/Astronautical Engineering from Massachusetts Institute of Technology in June 2015 and joined HPEPL as a graduate student in August 2015. Connie worked on liquid rocket engines as a propulsion lead on the MIT Rocket Team, where she helped design, build, and test a bi-propellant liquid rocket engine with an aerospike nozzle. As a propulsion intern for two summers at SpaceX, she worked on the Raptor engine designed to take humans to Mars. She has also done some work with electric propulsion at NASA Marshall Space Flight Center to model and simulate the physics of a multi-coil coilgun as an advanced attitude control system. At the MIT Space Propulsion Laboratory, she worked on the development of electrospray thrusters. Connie strongly believes in the necessity of advancing propulsion technologies to enable and expand human space exploration. Her interests include combining chemical and electric propulsion technologies to create new, more efficient propulsion systems, high-power Hall thrusters, and spacecraft engineering.

Scott King

Scott King

Graduate Research Assistant

Scott received his BS in Aerospace Engineering with high honor from Georgia Tech in May 2008. He has worked in the High-Power Electric Propulsion Laboratory (HPEPL) since January 2008, and joined as a graduate student in May 2008. He is currently researching a low-Earth orbit ion engine and high T/P Hall Effect thrusters. His interests include plasma physics, RF plasmas, and hypersonic aerodynamics.

Hisham Ali

Hisham Ali

NSTRF and Alfred P. Sloan Minority Fellow

Hisham earned a Bachelor of Science in Aerospace Engineering with minors in Mathematics and Computer-Based Honors from the University of Alabama in May 2013. In August 2013, he joined the Space Systems Design Laboratory as a graduate student and has also been a member of HPEPL since August 2017. In May 2015, he earned a Master of Science in Aerospace Engineering from the Georgia Institute of Technology. Hisham has had a lasting interest in in-situ resource utilization for spaceflight applications. As an undergraduate at the University of Alabama, Hisham worked with NASA’s Marshall Space Flight Center to identify, design, and test candidate parts for rapid prototyping in microgravity as part of NASA’s effort to demonstrate rapid prototyping on-board the International Space Station. Since arriving at Georgia Tech in 2013, he has worked to develop performance modeling capabilities and advance the state of the art for magnetohydrodynamics-based in-situ resource utilization during planetary entry. In addition, he has advanced this research while in residence as a Visiting Space Technologist at NASA’s Marshall Spaceflight Center, Langley Research Center, and Jet Propulsion Laboratory. In addition, he has designed and created an experimental testing platform for magnetohydrodynamic energy generation in conditions and configurations relevant to planetary entry. In January 2017, he advanced to doctoral candidacy in the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology. Hisham’s current research interests are in magnetohydrodynamics, hypersonics, plasma physics, space systems, and planetary entry systems. 

Undergraduate Research Assistants

HPEPL graduate students rely on the support of highly-skilled undergraduates in advancing their research forward. Below are the active undergraduate teams supporting VTF-1 and VTF-2.


Rob Ashcom

Matt Corado

Muhannad Eladl

Justin Johnson

Arega Margousian

Kelsey Pepper


Wyatt Amacker

Jordan Marshall

Adrian Vicente La Lande

Collin Whittaker

Thomas Wilson

Lab Alumni

"Few things are impossible to diligence and skill. Great works are performed not by strength, but perseverance." - Samuel Johnson

Jason Frieman, Ph.D.

NASA Glenn Research Center

Jonathan Walker, Ph.D.

Lockheed Martin - Skunk Works

Aaron Schinder, Ph.D.

Lockheed Martin - Skunk Works

Tyler Scogin, MS

NASA Marshall Space Flight Center

Natalie (Schloeder) Caruso, Ph.D.

Naval Research Laboratory

Samuel Langendorf, Ph.D.

Los Alamos National Laboratory

Carl Book, MS

Lam Research

Lake Singh, Ph.D.

The Aerospace Corporation

Brian Fein, MS

Independent Consultant

Sebastiano Giannelli, MS


Sherrie Hall, MS


Rafael Martinez, MS


Howell Hsieh, MS

U.S. Air Force

Alex Kieckhafer, Ph.D. (postdoc)

Zinn Technologies

Greg McCormick, MS

Georgia Tech Research Institute

Doug Palmer, MS

Booz Allen Hamilton

Gabriella Possa, MS

University of Brasilia

Logan Williams, Ph.D.

Naval Research Laboratory

Kunning Xu, Ph.D.

University of Alabama Huntsville

Cheong Chan, MS

Orbital ATK

Kybeom Kwon, Ph.D.

Republic of Korea Air Force Academy

Hoang Dao, MS

Aerojet Rocketdyne

Nils Gerrit Kottke, MS

TU Braunschweig, Germany

Mason Freeman, MS


Sean Barnes, MS

University of Maryland

Chenhoe Bae, MS

National Fusion Research Institute, South Korea

Brandon Sforzo, Ph.D. (postdoc)

Argonne National Laboratory