Research Team - UTSA Hypersonics

Faculty

Christopher Combs

Dr. Combs is the Dee Howard Endowed Associate Professor in Aerodynamics in the UTSA Department of Mechanical Engineering. He is also the Aerospace Engineering Program Director at UTSA, KCEID Associate Dean Fellow for Research, and Director of the Center for Advanced Measurements in Extreme Environments (CAMEE). Prior to starting at UTSA, Dr. Combs worked as a Research Assistant Professor at The University of Tennessee Space Institute. His primary area of research interest is in the development and application of non-intrusive diagnostic techniques for compressible flows and he also has extensive experience in investigations of hypersonic boundary layer and SWBLI flow physics. Dr. Combs is active with AIAA, ASME, and APS and is a current member of the AIAA Aerodynamic Measurement Technology Technical Committee.

E-mail: ccombs@utsa.edu
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Graduate Students and Post-Docs

Angelina Andrade

Angelina was born and raised in Dallas, Texas. She attended the University of North Texas from Fall 2016 to Fall 2019 and graduated with a B.S. in Mechanical and Energy Engineering. Following her undergraduate studies, Angelina continued her education as a graduate student at UTSA pursuing an M.S. in Mechanical Engineering with a thermal and fluid system concentration. She joined the Hypersonics Lab fall of 2021 and her current research interests are using laser diagnostics to study high-speed flows. She continued her research studies under Dr. Combs as a Ph.D. student starting fall of 2022.

David Balderas

David Balderas was born and raised in Corpus Christi, TX. He earned his B.S. degree in mechanical engineering from Texas A&M University Kingsville with a minor in aerospace engineering and mathematics. After graduating, David worked at L3Harris Technologies as a mechanical engineer doing structural design and analysis for military aircraft modifications. He began his M.S. in aerospace engineering at UTSA in the fall of 2023 and is working as a research assistant in the UTSA Hypersonics Lab.

Geneva Ballard

Geneva graduated from the University of Tennessee Knoxville in May 2024 with a B.S in Aerospace Engineering. During her undergraduate studies, she worked with the University of Tennessee Space Institute exploring hypersonic workforce development and RANS-based turbulence modeling of high-speed flows. Geneva worked at Mclaurin Aerospace performing advanced modeling and simulation of spacecraft and subsystems. She began her Masters program in Aerospace Engineering and Graduate Research Assistant Position with the Hypersonics lab at UTSA in Fall 2024.

Jennifer Colborn

Jennifer Colborn joined UTSA Hypersonics as a post-doctoral fellow in August of 2024. Previously, she earned her doctorate in mechanical engineering at Pennsylvania State University where she focused on analyzing convective and radiative heat flux in gas turbine combustion environments using a variety of sensors and laser diagnostics. Her bachelor’s in mechanical engineering and MS in aerospace engineering were completed at the University of Dayton in Ohio. While there, Jennifer focused on understanding controlling physics of sustainable aviation fuels at the Air Force Research Laboratory. She will continue her work with laser diagnostics at UTSA.

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Abinayaa Dhanagopal

Abinayaa Dhanagopal was born and raised in Chennai, India. She holds a bachelor’s degree in Aeronautical Engineering from India and a dual master’s degree from Iowa State University (ISU) in Aerospace and mechanical engineering. Leveraging low-speed fluid instabilities, she developed a wind energy harvesting apparatus using cantilevered piezoelectric actuators at ISU’s multiphase flow research laboratory. She joined the Combs Research Group at UTSA in the fall of 2022 as a Ph.D. student. Her research interests lie in hypersonic aerodynamics, combustion, and laser diagnostics. She considers space a unifying force, draws inspiration from space exploration’s technological and philosophical bearings, and eventually hopes to build a career in the same.

David Kendhammer

David was born in La Crosse, WI, and went to the University of Wisconsin – La Crosse and the University of Wisconsin – – Platteville for bachelor’s degrees in Physics and Mechanical Engineering through a dual-degree program. This included research in nuclear physics and piezoelectric materials. He then went to Iowa State University for Aerospace Engineering with a focus on orbital dynamics. His thesis was the improvement to a solution for the Global Trajectory Optimization Competition 11 problem statement. In the Fall of 2022, he began his Ph.D. Studies at the University of Texas at San Antonio in Mechanical Engineering with a focus in thermal and fluid systems and is a part of the UTSA Hypersonic Laboratory.

Katherine Kim

Katherine Kim was born and raised in Houston, TX. She received her Bachelor’s degree in Aerospace Engineering at the University of Texas at Austin in 2022. During her undergraduate studies, she became the student director of the Texas Spacecraft Laboratory (TSL) and one of the student directors of the Texas Rocket Engineering Laboratory (TREL). Additionally, she worked as a Data Analysis intern at the NASA Ames Research Center to support lunar dust mitigation technologies. She is currently pursuing a Ph.D. in Mechanical Engineering under the mentorship of Dr. Combs.

Elijah LaLonde

Elijah LaLonde was born in Alvin, Texas in 1996. He earned his B.S. in physics, graduating Summa Cum Laude, in 2018 from Texas State University in San Marcos, Texas. He did undergraduate research in photovoltaics at Texas State University from the summer of 2018 until graduating at the end of 2018. After finishing his undergraduate studies, he took a year to continue his research in photovoltaics and explore his interests in Electromagnetic Field Theory and Fluid Dynamics. In the fall of 2020, he began his Ph.D. in Mechanical Engineering at UTSA as a part of the Combs research group. Since then, he has worked with SwRI on the CONNECT project and is currently studying hypersonic separation events through a grant awarded through the University Consortium for Applied Hypersonics.

Juan David Navarro

Juan David was born in Santiago de Cali, Valle del Cauca (Colombia). He obtained his bachelor’s degree in Mechanical Engineering from Universidad EAFIT in 2015. Following his graduation, he received a scholarship from Universidad EAFIT to pursue a Master of Sciences in Engineering under the direction of Dr. Juan Camilo Isaza. During his masters’ studies, he visited Cornell University for a research internship with Dr. Gregory Paul Bewley. Upon graduation in 2019, Juan David joined the Advanced Materials and Mechanical Systems Laboratory at The University of Texas at San Antonio where he finished his doctorate in 2023 under the direction of Dr. David Restrepo. Juan David then continued at UTSA as Postdoctoral Fellow designing novel architected metamaterials for drag reduction and flow control in hypersonic vehicles.

Kevin Posladek

Kevin Posladek was born in San Diego, California and received his bachelor’s degree in mechanical engineering from the University of Texas at San Antonio, with an undergraduate research focus on subsonic wind tunnel design and testing. He joined the UTSA Hypersonics Lab in 2022 and worked as an Operations Engineering intern at NASA Armstrong Flight Research Center that same year, where he worked towards calibration of the X-59 Low Boom Flight Demonstrator air data system. He is currently pursuing a Ph.D. in Mechanical Engineering with a research focus in shock-wave/boundary-layer interactions.

Christopher Renfro

Christopher Renfro grew up in San Antonio, Texas and received his Bachelor of Science in Aerospace Engineering at the University of Texas at Austin in 2023. He is now pursuing a Master of Science in Aerospace Engineering at the University of Texas at San Antonio, where he is engaged in hypersonic research under Dr. Combs. He also can read Latin and Old English (to a certain extent).

Joseph Rutherford

Joseph Rutherford was born and raised in Tennessee, where during high school he obtained a technical degree in Aviation Maintenance Technology from Northeast State Community College. He went on to attend The University of Tennessee, Knoxville where in 2023 he earned his B.S in Aerospace Engineering with an honors concentration. At the University of Tennessee, he worked as an undergraduate researcher under Dr. Uday Vaidya focused on Carbon-Carbon composites manufacturing research for hypersonic applications. He joined the University of Texas at San Antonio in 2024 for his Ph.D. in Mechanical Engineering under the guidance of Dr. Christopher Combs and Dr. Guillermo Araya working on high-speed analytics of hypersonic flows.

Nick Stegmeier

Nick is from South Dakota and received his B.S. and M.S. in mathematics from South Dakota State University (SDSU) where he studied parallel numerical methods for partial differential equations. During his time at SDSU, he interned at Los Alamos National Laboratory and developed software for computational physics and high performance computing. Since graduating with his M.S. in 2019, he has interned at KBR/EROS working on machine learning for satellite imagery, Montana Space Grant Consortium launching high altitude balloons, and NASA Johnson Space Center analyzing spacecraft re-entry aerothermodynamic heating. Nick decided to return to SDSU to finish his B.S. in mechanical engineering, which he completed in May of 2023, and renewed his interest in fluid dynamics. He is now pursuing a Ph.D. in Mechanical Engineering at UTSA and researching high speed flow as part of Dr. Chris Combs’ hypersonics research lab.

Nathan Strasser

Nathan grew up in Greensboro, North Carolina, and graduated in May 2022 from UNC-Wilmington with a B.S. in Chemistry and a minor in Mathematics. He interned at a biotech startup over the summers, developing a conventional vaccine technology used to make a COVID-19 vaccine and a quadrivalent flu vaccine. During the school year, he researched optimization of mutated T7 polymerase to suppress mRNA byproducts. He is pursuing a Ph.D. in Mechanical Engineering and conducting research in the Combs Hypersonic Lab. Nathan plans to use his skillset in chemistry to advance hypersonic research before and after graduation.

Undergraduate Students

Chun Chieh Ai (Jerry)	Chun Chieh Ai (Jerry) was born in Taiwan and immigrated to the United States in 2017. He is currently a fourth-year undergraduate student at UTSA, pursuing a B.S. in Mechanical Engineering. Jerry joined Dr. Combs’ research lab in Spring 2024, hoping to gain research experience and knowledge in the Aerospace field. In his free time, he enjoys playing video games and watching movies.
Jonah Barbosa	Jonah Barbosa was born and raised in San Antonio, Texas. He is currently an undergraduate student at UTSA pursuing his second bachelor’s degree in Mechanical Engineering. Before pursuing a degree in Mechanical Engineering, Jonah first attended Texas A&M University where he graduated Spring of 2020 with a B.S. in applied exercise physiology with a minor in psychology. He joined the UTSA Hypersonic lab in late spring of 2022 and since then he has helped with experiment operations and looks forward to continuing to grow his understanding of non-intrusive diagnostics specifically with Schlieren imaging.
Andrew Cervantes	Andrew Cervantes was born and raised in San Antonio, Texas, and is currently a fourth-year mechanical engineering undergraduate student at UTSA. He joined Dr. Combs’ Hypersonic Lab at the beginning of his junior year and has been working as an undergraduate research assistant. Andrew also serves as an officer of the AIAA chapter at UTSA. He hopes to further his interest in aerospace by pursuing a master’s program after graduation. In his free time, Andrew enjoys drumming, designing furniture, and driving while listening to music.
Ricardo RJ” Garza	Ricardo “RJ” Garza is a third-year mechanical engineering undergraduate at UTSA and member of AIAA. He currently works in the Hypersonic Lab as an undergraduate research assistant, mentored by Juan Navarro. His most recent project consists of assisting in the research of architected materials for drag reduction and flow control in hypersonic vehicles. He plans to obtain an aerospace certificate and pursue a masters degree in aerospace engineering. In his free time, he enjoys working out, listening to music and watching documentaries.
Sofía Gutiérrez	Sofía Gutiérrez is a sophomore Mechanical Engineering student at the University of Antioquia in Medellin, Colombia. She has taken courses in robotics, programming, scientific computing, data analysis, engineering, and languages such as English, French, and German. She was part of the electric traction vehicle team at the University of Antioquia, “Squalo Martello,” in charge of the 3D design for the vehicle’s cockpit, implementing aerodynamic requirements to the user’s needs. She belongs to the Mechanical Design Research Group (GDM) at the University of Antioquia. She is the leader of the “APIDAE (Adaptación Producción e Investigación de Drones de Alta Eficiencia)” Research line, which focuses on designing and manufacturing drones, where she specializes in generative design and additive manufacturing. During the 2022 Spring, she did a research internship on generative design and topological optimization of drone structures at Saint Mary’s University in San Antonio, Texas. During the Summer of 2022, she worked as a CAMEE research intern at the Hypersonics lab at the University of Texas at San Antonio, assisting with high-speed wind tunnel testing and developing data and image analysis with shock wave/boundary layer interaction, pressure-sensitive paint, shade tracking, background subtraction, spectral analysis. She will pursue a Ph.D. in Mechanical and Aerospace engineering to make her dream come true of being a NASA scientist. She enjoys nature and art and loves trail running in her free time.
Patrick Hughes	Patrick Hughes is a third-year undergraduate student at UTSA majoring in mechanical engineering and minoring in civic engagement. He joined the UTSA Hypersonics Laboratory in Fall of 2022, where he assists with facility operation, non-intrusive diagnostics, and data processing. Patrick interned at NASA Johnson Space Center in Summer 2024, where he worked to develop and prototype a two-stage recovery system for NASA’s HyperSTEP Project, a subscale Mid-L/D spacecraft designed as a low-cost hypersonic flight test platform for advancing entry technologies. After graduating, Patrick hopes to obtain a Master’s Degree in aerospace engineering and work in the field of spaceflight. In his free time, he enjoys reading (Sci-Fi/History), camping, and making coffee.
Jacob Kachich	Jacob Kachich was born in Houston Texas and, is nearly done with his mechanical engineering degree. After invited into the lab, he had made himself at home. He has lended a helping hand with circuity in the lab along with designing printable testing equipment. Currently as an undergraduate research assistant, he aspires to broaden his skills even further from the experience gained at the hypersonic lab. On his spare time, he likes to design and, 3D print mechanisms.
Rafael Lopez	Rafael is a second-year mechanical engineering undergraduate at UTSA. He was raised in Washington state where he earned his associates degree in Aviation Maintenance. He transferred to UTSA in fall 2022 to pursue a bachelors in mechanical engineering. Rafael currently works in the Hypersonics Lab as an undergraduate research assistant, mentored by Kevin Posladek. In his free time, he likes working on his Miata, playing video games, and thrifting. Rafael is also the secretary for the UTSA chapter of AIAA.
Alexandria Lopez-Boor	Alexandria Lopez-Boor was born and raised in San Antonio, TX. She is currently a third-year Chemical Engineering student at UTSA involved in multiple organizations such as the American Institute of Chemical Engineers (AIChE) and the Aeronautics and Rocket Club (ARC). Since joining the Hypersonics Lab in Spring 2024 as an undergraduate research assistant, she has been involved in research with phononic metamaterials to decrease shock-wave/boundary layer interactions and hopes to continue her career into the defense industry. She hopes to further her knowledge in vehicle design and thermal protection systems, but in her free time, she enjoys playing golf and spending quality time with friends.
Devin Moltz	Devin Moltz was born and raised in San Antonio and is currently in his 4th year of a mechanical engineering undergraduate degree at UTSA. He aims to obtain the aerospace certification for undergraduates by the time he graduates in December of 2023. Devin began working in Dr. Combs’ hypersonic lab in early 2022 and has developed skills in CFD and Python along with learning how to run experiments and assist the graduate students. In the summer of 2023, Devin was an intern for the lab where he helped to produce CFD models of simulations such as hypersonic nozzles and an IC3X geometry. In his free time, he likes to play video games with friends, work out, and take his dog out for hikes or to the park.
Brenda Perez	Brenda Perez was born and raised in Laredo, Texas. She began her undergraduate studies at Texas A&M International University in 2019, and in the fall of 2021, Brenda transferred to UTSA to pursue a bachelor’s degree in Mechanical Engineering. In the spring of 2022, she joined UTSA’s Hypersonics Lab where she is currently working as an undergraduate research assistant. Her current projects include assisting in the research of hypersonic separation events and developing a new data acquisition triggering system to use during wind tunnel testing. In her free time, Brenda enjoys reading, working on art projects, and spending time with her friends.
Isaias Rangel	Isaias Rangel was born and raised in San Antonio, Texas. He began his undergraduate studies at the Alamo Colleges in 2017 and participated in their CIMA program in partnership with UTSA to enhance his research experience. In 2020, he transferred to UTSA to continue his pursuit of a bachelor’s degree in Mechanical Engineering. In the Fall of 2023 as a senior, he joined Dr. Combs’ hypersonic lab working as an undergraduate research assistant hoping to further enhance his research experience and break into the aerospace field after he graduates. In his free time, he enjoys producing music, going to concerts, and watching movies.
Edward Gonzalez Rebollar	Edward was born in Mexico City and raised in San Antonio, Texas. He is currently a third-year undergraduate student at UTSA pursuing a B.S. in Mechanical Engineering with a minor in Business Administration. Edward joined Dr. Combs’ research lab in Spring 2022 and is currently assisting in research on hypersonic separation events funded through the University Consortium for Applied Hypersonics. After graduation, he plans on pursuing a Master’s degree in Aerospace Engineering. In his spare time, he enjoys hanging out with friends and playing the guitar.
Neil Sawant	Neil Sawant is a second-year mechanical engineering undergraduate at UTSA. He is from India and came to UTSA for his undergraduate studies in 2021. He joined Dr. Combs’ lab in the Summer of his Freshman year as a Citymester intern. He currently works with the Hypersonics Lab as an undergraduate research assistant, helping run experiments and designing equipment for the lab. After graduating, Neil hopes to complete a Master’s Degree in Aerospace Engineering from a prestigious institution. In his free time, he likes playing video games, occasionally mountain bikes, and works with the FSAE club at UTSA.
Alexis Seals	Alexis Seals was born into a military family and has lived in Mississippi, Florida, Japan, and Washington before settling in San Antonio, her current home. Now in her third year as a mechanical engineering student at UTSA, she joined Dr. Combs’ research group in Fall 2023. As an undergraduate research assistant in the Hypersonics Lab, Alexis works under the mentorship of Kevin Posladek and Katherine Kim, working on ORNL and future UCAH projects. She also serves as the Career and Professional Development Chair for the student chapter of AIAA and plans to pursue a master’s degree in aerospace engineering. In her free time, Alexis enjoys traveling, listening to Taylor Swift, and exploring coffee shops.

Alumni

Graduate: Stephanie Cottier (MS ’19, St. Mary’s U.); Prince Dukuze (MS ’20, CPS Energy); Raj Patel (MS ’21, Axiom Space); Diego Bass (MS ’21, Navistar); Dean Kaialau (MS ’21, Aerospace Corp.); Matt Garcia (MS ’22, US Navy); Valeria Delgado (MS ’22); Brandon Donald (MS ’22, Firefly Aerospace); Eugene Hoffman (PhD ’23, Southwest Research Institute)

Undergraduate: George Gonzalez (BS ’19, Boeing), DJ Bell (BS ’19, Boeing), Christopher Kunz (BS ’19, Boeing), Anmar Jabbar (BS ’19, Pike Corp.), Jordan Foster (BS ’20, L3 Harris), Dean Kaialau (BS ’20), Tomas Bello (BS ’20, HEB), Diana Magana (BS ’20, HEB), Raj Patel (BS ’20), Matt Garcia (BS ’20), Michael Rittenberry (BS ’20), Natasia Upadhaya (BS ’20), Ivana Chen (BS ’22, Rolls Royce), Hayden Bilbo (BS ’22), Austin Rendon (BS ’22, JHU-APL), Veronika Granado (BS ’23)