PLANETAS Group Members

Dr. Frances Rivera-Hernández (she/ella)
Assistant Professor, Georgia Tech 
Co-director, Georgia Tech Astrobiology Program

Postdoctoral Researcher, Dartmouth College, 2018-2020
Ph.D. Geology, University of California at Davis, 2018
M.S. Earth & Space Sciences, University of Washington, 2014
B.S. Geology; B.S. Astrophysics, University of Wyoming, 2009

Dr. Frances Rivera-Hernández runs the PLANETAS group at the Georgia Institute of Technology (Georgia Tech). She is an Assistant Professor in the School of Earth & Atmospheric Sciences and Co-director of Georgia Tech’s Center for Astrobiology. She is also Deputy PI for the  NASA SSERVI center at Georgia Tech: Center for Lunar Environment and Volatile Exploration Research (CLEVER). Her research is focused on characterizing planetary surfaces (sedimentary deposits and landforms) to help interpret present and past surface conditions and habitability on Earth, Mars, Moon, and beyond! Outside of research, she remains active in several outreach and informal education projects to encourage students from underrepresented communities to pursue STEM careers.

She is a native of Aguas Buenas, Puerto Rico (¡Wepa!) and has been in love with science for as long as she can remember. When she is not sciencing, she enjoys spending time with her family, traveling and walking in new cities, learning new languages, cooking, and trying new restaurants.

For more details on her research and background check out her personal website.

Fluent in Español, Spanglish, & English.

CV (updated January 2025)

Dr. Jordan Bretzfelder (she/her)
Postdoctoral Researcher, Georgia Tech

NASA Postdoctoral Fellow, Marshall Space Flight Center, 2024-2025  
Ph.D., University of California at Los Angeles, 2024
B.S., Physics, University of Southern California, 2019

Dr. Jordan Bretzfelder officially joined the PLANETAS group in the August 2025. Her main research interests are in aeolian geomorphology and has used experimental, field, and remote sensing studies to better understand wind driven processes on planetary surfaces. Before Georgia Tech, she was a NASA Postdoctoral Fellow at Marshall Space Flight Center where she worked with Dr. Michael Zanetti and a graduate student at UCLA where she worked with Dr. Mackenzie Day. Find out more about her research here.

Contact: jbretzfelder3@gatech.edu

Dr. Emily (Emmy) Hughes (she/her)
Postdoctoral Researcher, Georgia Tech

Ph.D. Earth & Atmospheric Sciences, Georgia Institute of Technology, 2025
B.S., Earth and Environmental Science; English, Wesleyan University, 2020

Dr. Emmy Hughes originally joined the PLANETAS group as a graduate student in 2022 and in August 2025 transitioned to a Postdoctoral Researcher. She is interested in aqueous geochemistry, astrobiology, and spectroscopic studies of planetary surfaces. For her PhD, she mainly worked on better understanding brine systems under freezing conditions relevant to Mars paleolakes by combining field work in British Columbia, FREZCHEM modeling, and experimental studies. She is continuing some of this work as a Postdoc but applying it to Antarctic paleolake deposits and dune and interdune environments at White Sands National Park. She’s also a member of the Curiosity rover’s ChemCam LIBS instrument team. Find out more about her research on her personal website.

Contact: ehughes36@gatech.edu

Tatiana Gibson (she/her)
Graduate student, Georgia Tech

B.S. Environmental Earth and Soil Science, Cal Poly: San Luis Obispo, 2021

Tatiana joined the PLANETAS group in the Fall of 2021. She is interested in astrobiology, geomorphology, and the water history of Mars as recorded in fluvial deposits and paleolake basins. She is currently working on characterizing the sedimentology and transport history of conglomeratic boulders and cobbles in Gale crater, Mars using images taken by the MAHLI and Mastcam cameras on the Curiosity rover. She’s a member of the Curiosity rover’s MAHLI instrument team.

Contact: tgibson42@gatech.edu

Sharissa Thompson (she/her)
Graduate student, Georgia Tech

B.S. Geological Sciences, Salem State University, 2021

Sharissa joined the PLANETAS group in the Fall of 2021. She is interested in surface processes, geomorphology, and experimental studies of sediment-water flows. She is currently using experimental studies in a pressure chamber to characterize how changes in pressure, temperature, and water-rock ratios affect the transport and deposition of sedimentary flows on Mars. She’s also a member of the Curiosity rover’s MAHLI instrument team.

Contact: sthompson318@gatech.edu

Alivia Eng (she/her)
Graduate student (PhD)

M.S., Geology, Western Washington University, 2023
B.S., Geology; Minor Astronomy, Western Washington University, 2021

Alivia officially joined the PLANETAS group in the Fall of 2023. She is interested in surface processes and spectroscopic studies of planetary surfaces. During her PhD she has been working on (1) characterizing composition of martian rocks using ChemCam Passive specta, (2) connecting Mastcam and Mastcam-Z multispectral data to HiRISE and CaSSIS color images to better inform on the compositional properties of Mars, and field analog studies of volcanic terrains with orbital and drone multispectral data to better understand limitations of Mars analyses. She’s also a member of the Curiosity rover’s Mastcam and ChemCam’s instrument teams.

Jelis Sostre Cortés (she/her)
Graduate student (PhD)

B.S., Geology, University of Puerto Rico-Mayagüez, 2023

Jelis is officially joined the PLANETAS group in the Fall of 2023. She is interested in planetary geology, field analog studies, astrobiology, and geohazards. For her PhD she mainly has been working on characterizing volcanic and aeolian terrains with orbital and drone based thermal infrared datasets to better interpret surface properties such as cohesiveness, grain size, and roughness. She’s a member of the Curiosity rover’s MAHLI instrument team.

Dr. Karin Lehnigk (she/her)
Postdoctoral Researcher, Georgia Tech

Postdoctoral Researcher, Georgia Tech, 2022-2024
Ph.D. Geosciences, University of Massachusetts, Amherst, 2022
B.S. Geology, College of William & Mary, 2016

Dr. Karin Lehnigk was a member of the PLANETAS group from October 2022 to December 2024. She is interested in surface processes on Earth and Mars, particularly the role of catastrophic floods in shaping topography. Dr. Lehnigk collaborated with the PLANETAS group, the TECHtonics group with Dr. Karl Lang, and the Smithsonian Air & Space Museum to study the incision history of the Ares Vallis canyon on Mars and outburst floods associated with Jezero crater. Find out more about her research on her personal website. Dr. Lehnigk is now an NPP Postdoc at NASA Goddard.

Contact: klehnigk3@gatech.edu

Dr. Benjamin McKeeby (he/him)
Postdoctoral Researcher, Northern Arizona University

Ph.D. Geology and Planetary Science, University of Pittsburgh, 2022
M.A. Geology and Planetary Science, Wesleyan University, 2017
B.S. Geology, Stony Brook University, 2013

Dr. Benjamin McKeeby was in the PLANETAS group from 2022-2024 bringing with him expertise in thermal infrared spectroscopy and thermophysical modeling. He is interested in planetary surface processes and surface evolution. Dr. McKeeby worked with Dr. Rivera-Hernández on the development and testing of a semi-autonomous legged robot LASSIE with the goal of better understanding the roles that water and ices play in modifying planetary surfaces. He also developed a protocol for using TIR methods for characterizing alluvial fan surfaces on Mars. Ben is also a member of the THEMIS science team and THEMIS off-nadir working group. Find out more about his current and past research on his personal website.

Contact: benjamin.mckeeby@nau.edu

Dr. Jacob Adler (he/him)
Assistant Research Professor, Arizona State University

Postdoctoral Researcher, Georgia Tech, 2021-2022
Ph.D. Geological Sciences, Arizona State University, 2019
B.S. Geophysics and Space Physics, University of California, Los Angeles, 2013

Dr. Jacob Adler was a member of the PLANETAS group from April 2021-August 2022. He worked with Dr. Rivera-Hernández on evaluating how different orbital data sets can be synthesized to optimize characterization and mapping of alluvial fan surfaces on Earth and Mars. He also worked with graduate student, Sharissa Thompson, on mud flow experiments in a Mars chamber. Dr. Adler is now an Assistant Research Professor at the Arizona State University and leads the Adler Lab group. 

Contact: Jacob.B.Adler@asu.edu

Allie Hearn (she/her)
Undergraduate student, Georgia Tech

B.S. Physics, Georgia Tech, In Progress

Allie is working with Dr. Ben McKeeby, Emmy Hughes, and Dr. Frances Rivera-Hernández. She is helping create a LIBS calibration library of Mars analog geologic materials for a SciAps Z-300.

Lizbeth (Lizzie) Minaya (she/her)
Undergraduate student, University of Massachusetts Amherst, NASA SUPPR Intern Summer 2023

B.S. Geology, University of Massachusetts Amherst, In Progress

NASA SUPPR Summer 2023 intern working with Dr. Frances Rivera-Hernández, Dr. James Wray, and graduate students Sharissa Thompson and Tatiana Gibson. She is working on better understanding the water history recorded in the Jezero crater outlet channel on Mars by combining geomorphological and compositional analysis from orbital based datasets.  

Sydney Kamakaila Peters (she/her)
Undergraduate student, California State University, Fresno, REU Intern Summer 2023

B.S. Geology, California State University Fresno, In Progress

GT EAS REU student working with Dr. Ben McKeeby, Emmy Hughes, and Dr. Frances Rivera-Hernández. She will be helping create an XRF calibration library of Mars analog geologic materials for a SciAps X-250.

Grace Fanson (she/her)
Graduate student, Massachusetts Institute of Technology

Ph.D. Planetary Science, Massachusetts Institute of Technology, In Progress
B.S. Physics; concentration Astrophysics, Georgia Tech, 2022

Grace worked as an undergraduate researcher with Dr. James Wray (main advisor) and Dr. Frances Rivera-Hernández on a study of potential volcanism in the Arabia Terra region of Mars using CRISM data. Starting Fall 2023 Grace will be a graduate student at MIT working with Dr. Gaia Stucky de Quay. Check out Grace’s website here.

Hailey Bos (she/her)
Undergraduate student, University of Georgia

B.S. Geology, University of Georgia, Starting Fall 2023
B.S. Earth & Atmospheric Sciences, Georgia Tech, 2022-2023

Hailey worked as an undergraduate student with Tatiana Gibson and Dr. Frances Rivera-Hernández on characterizing grain size of conglomerates in Gale Crater using Mastcam images. Hailey transferred from Georgia Tech to the University of Georgia where she will be starting Fall 2023. 

Elana Alevy (she/her)
Undergraduate student, Colby College, NASA SUPPR Intern Summer 2022

B.S. Geology, Minor Astronomy, Colby College, In Progress

NASA SUPPR Summer 2022 intern working with Dr. Frances Rivera-Hernández. She is conducting a quantitative geomorphic study of terraces in Miers Valley, Antarctica to evaluate whether they are paleoshorelines associated with proposed Glacial Lake Trowbridge.

Christina Singh (she/her)
Undergraduate student, Connecticut College, REU Intern Summer 2022

B.S. Physics; concentration Astrophysics, Double Minor inMathematics and Geoscience, Connecticut College, 2023

EAS REU Summer 2022 intern working with Dr. Frances Rivera-Hernández and Dr. Jacob Adler. She is conducting a geomorphic and stratigraphic study of a stack of layered deposits in Chryse Planitia, Mars to determine whether they remnants of the Hypanis delta.

Abigail Russ (she/they)
Undergraduate student, Georgia Tech

B.S. Physics, Georgia Tech, 2023

Abigail worked as an undergraduate student with Dr. Adler on using the COMSOL software to model martian mudflows.

Grace Kim (she/her)
Graduate student, Georgia Tech

B.S. Geological Sciences, SUNY University at Stony Brook, 2019

Grace worked with Dr. Rivera-Hernández on characterizing Curiosity ChemCam LIBS compositional trends with grain size for conglomerates in Gale crater, Mars. She is now a member of Dr. Jean Lynch-Stieglitz paleoceanography and paleoclimatology group.

Margaret (Maggie) Burdell (she/her)
Undergraduate student, University of Georgia, REU Intern Summer 2021

B.S. Geology, University of Georgia, In Progress

Maggie worked with Dr. Rivera-Hernandez on characterizing the sedimentary properties of conglomerates imaged by the Curiosity rover to qualitatively provide insights into the hydrology of ancient rivers in Gale crater, Mars.

Sara Cuevas Quiñones (she/ella)
Undergraduate student, Purdue, REU Intern Summer 2021

B.S. Physics, Purdue University, In Progress

Sara worked with Dr. James Wray (main advisor) and Dr. Rivera-Hernandez on providing insights into the origin of a mound on Jezero crater’s rim by characterizing its morphological and mineralogical properties.