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Samuel Howell

Photo of Samuel Howell


4800 Oak Grove Drive
M/S 183-301

Pasadena, CA 91109

Curriculum Vitae:

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Member of:

Planetary Interiors and Geophysics


Samuel is an Ocean Worlds Scientist constraining processes that support the habitability of worlds within our solar system that contain deep, unexplored oceans. Dr. Howell supports the exploration of Ocean Worlds as Project Staff Scientist on the Europa Clipper mission, and leads science development for multiple future concepts to enable planetary ice shell and ocean access.

Samuel is the Principal Investigator of the NASA-funded ORCAA analogue mission, which will conduct access a subglacial lake in the Juneau Icefield with a planetary “cryobot” to simulate a potential future mission to Europa. Additionally, he is Lead Scientist for JPL's PRIME cryobot concept, CryoComm through-ice communications system, and NASA’s SWIM technology concept for planetary ocean exploration.

Samuel obtained his B.S. in Engineering Physics from the Rose-Hulman Institute of Technology with a concentration in Mechanical Engineering and minor in Thermal Fluid Mechanics. He obtained his M.S. and PhD in Geology and Geophysics University of Hawaiʻi at Mānoa, where he explored planetary-scale process through studies of local surface features. His research on Earth, the first-discovered Ocean World. Samuel’s graduate research garnered national attention, including a 2016 Popular Mechanics Breakthrough Award for innovation detecting and predicting motions on the San Andreas Fault.

In his spare time, he has climbed Mount Kilimanjaro, remotely piloted sonar at the Marianas Trench, and serendipitously met his wife, Marissa, an expert on the surfaces of icy moons and PILOT for the Mars Perseverance Rover.


PhD 2016 Geology and Geophysics, University of Hawaiʻi at Mānoa, Honolulu, Hawaiʻi

MS 2013 Geology and Geophysics, University of Hawaiʻi at Mānoa, Honolulu, Hawaiʻi

BS 2010 Engineering Physics, Rose-Hulman Institute of Technology, Terre Haute, Indiana

Professional Experience


2019 – Pres. Project Staff Scientist, NASA Europa Clipper Mission

2019 – Pres. Concept Scientist, JPL Probe using Radioisotopes for Icy Moon Exploration (PRIME)

2018 – Pres. Steering Committee, Network for Ocean Worlds (NOW), NASA Astrobiology Program

2017 – 2019 Project Science Affiliate, Europa Clipper Science Team

ACTIVE FUNDED PROJECTS (PI = Principal Investigator, Co-I = Co-Investigator)

PI (2022-2025) ORCAA: Ocean Worlds Reconnaissance of Astrobiological Analogues, NASA PSTAR.

PI (2022-2024) How many cracks does it take to get to the ocean of Enceladus? JPL Topical Grant.

PI (2021-2024) Europa’s Icy Tectonics: First-Principles and High-Order Modeling, Solar System Workings.

Co-I (2021-2024) Thermal Measurements of Icy Europan Analog Materials, Solar System Workings.

Co-I (2021-2023) Maturation and demonstration of technology to enable through deep-ice communication (CryoComm) on Europa, Concepts for Ocean worlds Life Detection Technology.

Co-I (2021-2023) SWIM - Sensing with Independent Microswimmers, NASA Innovative Advanced Concepts

Co-I (2020-2023) Did Solid Tides Prevent the Thermodynamic Death of Europa? Habitable Worlds.

Co-I (2020-2023) Compositions of Ice Shells on Ocean Worlds, Solar System Workings.


2022 Session Co-chair, Ocean Worlds and Icy Volcanism: The Briny Deep, 53rd (LPSC)

2022 Primary Convener, The Diverse Ocean Worlds, Astrobiology Science Conference (AbSciCon)

2022 Co-convener, Ocean Science for Ocean Worlds, Ocean Sciences Meeting (OSM)

2021 Program Committee, 52nd Lunar and Planetary Science Conference (LPSC)

2021 Primary Convener, Special Session on The Next Two Decades of Ocean Worlds Exploration (LPSC)

2021 Subject Matter Expert, Dynamic Radioisotope Power Systems Mission Study, NASA RPS Program

2020 Co-convener, Icy Satellite Surfaces and Below, AAS Division of Planetary Sciences (DPS) Meeting

2020 Study Scientist, Radioisotope Power Systems for Pressure Vessels, NASA RPS Program

2020 Selected Participant, NASA Principle Investigator Launchpad (Mission-focused). NASA SMD

2019 Study Scientist, Radioisotope Power System Considerations for Ocean Worlds, NASA RPS Program

2017 Subject Matter Expert, Keck Institute for Space Studies: Accessing Subsurf. Oceans of Icy Worlds

Research Interests

Samuel’s current and proposed research places studies of planetary interiors into the context of the search for life. Active research interests include the mechanisms and timescales of ocean world energy transport, material mixing, and evolution, as well as the exchange of materials between interior oceans and outer ice shells.

Selected Awards

2023 Voyager Award for Europa Clipper Strategic Science Plan development, JPL

2022 Voyager Award for Europa Clipper science visualization tool development, JPL

2021 Voyager Award for Europa Clipper Lecture Series, JPL

2021 Team Award for contributions to the Decadal Survey in Planetary Science and Astrobiology, JPL

2017 Outstanding Postdoctoral Research in Planetary Science and Life Detection, JPL

2016 Popular Mechanics Breakthrough Award for innovative method to study San Andreas Fault motions

Selected Publications


Howell, S., C. J. Bierson, K. Kalousová, E. J. Leonard, G. Steinbrügge, N. Wolfenbarger (2023, in prod.). Jupiter’s Ocean Worlds: Dynamic Ices and the Search for Life, in Ices in the Solar System: A Volatile Excursion from Mercury and the Moon to the Kuiper Belt and Beyond, Elsevier.

Howell, S., E. J. Leonard (2023, in prod.). Ocean Worlds: Interior Processes and Physical Environments, NASA Handbook of Space Resources, Springer Publishing.

Mills, M. M., R. T. Pappalardo, M. P. Panning, E. J. Leonard, S. M. Howell, Moonquake-triggered mass wasting processes on icy satellites. Icarus, doi: 10.1016/j.icarus.2023.115534.

Howell, S. (2022), Likely thickness of Europa’s icy shell. Planetary Science Journal, doi:10.3847/PSJ/abfe10.

Lesage, E., H. Massol, S. Howell, F, Schmidt. (2022). Simulation of Freezing Cryomagma Reservoirs in Viscoelastic Ice Shells. The Planetary Science Journal, doi: 10.3847/PSJ/ac75bf

Leonard, E. J., S. Howell et al. (2022). Finding order in chaos: Quantitative predictors of chaos terrain morphology on Europa. Geophysical Research Letters, doi:10.1029/2021GL097309.

DiNicola, M., S. Howell, et al. (2022). Resurfacing: An Approach to Planetary Protection for Geologically Active Ocean Worlds. The Planetary Science Journal, doi:10.3847/PSJ/ac642d.

Howell, S.., et al. (2021). Ocean Worlds Exploration and the Search for Life, Bulletin of the American Astronomical Society, doi:10.3847/25c2cfeb.8920f9ae.

Ermakov et al., incl. S. Howell, (2021). A Recipe for the Geophysical Exploration of Enceladus, The Planetary Science Journal, doi:10.3847/PSJ/ac06d2.

Bairstow, B. Y. Lee, S. Howell, B. Donitz, M. Choukroun, S. Perl (2021). Thermal Analysis of Landers using Radioisotope Power Systems on Ice Worlds, IEEE, doi:10.1109/AERO50100.2021.9438303.

Howell, S., R. T. Pappalardo (2020). NASA’s Europa Clipper—a mission to a potentially habitable ocean world? Nature Communications, doi:10.1038/s41467-020-15160-9.

Zacny, K. et al., incl. S. Howell (2020). Extraterrestrial Drilling and Excavation, in Advances in Terrestrial and Extraterrestrial Drilling: Ground, Ice, and Underwater, CRC Press, ISBN 9781138341500.

Howell, S., R.T. Pappalardo (2019). Can Earth-like plate tectonics occur in the outer ice shells of icy satellites? Icarus, doi:10.1016/j.icarus.2019.01.011.

Howell, S., J-A. Olive, G. Ito. M. D. Behn, J. Escartin, B. Kaus (2019), Seafloor expression of oceanic detachment faults reflects gradients in mid-ocean ridge magma supply, Earth and Planetary Science Letters, doi:10.1016/j.epsl.2019.04.001.

Howell, S., L. Chou, 18 others (2018). Centaur reconnaissance mission concept: Chariklo flyby and impact, Planetary and Space Science, doi:10.1016/j.pss.2018.07.008.

Howell, S., R.T. Pappalardo (2018). Band formation and ocean-surface interaction on Europa and Ganymede, Geophysical Research Letters, doi:10.1029/2018GL077594.

Howell, S., B. Smith-Konter, N. Frazier, X. Tong, D. Sandwell (2016). The vertical fingerprint of earthquake cycle loading in Southern California, Nature Geoscience, doi:10.1038/ngeo2741.

Howell, S., G. Ito, M. D. Behn, F. Martinez, J.-A. Olive, and J. Escartín (2016), Magmatic and tectonic extension at the Chile Ridge: Evidence for mantle controls on ridge segmentation, Geochem. Geophys. Geosyst., doi:10.1002/2016GC006380.

Howell, S., G. Ito, A.J. Breivik, A. Rai, R. Mjelde, B. Hanan, K. Sayit, P. Vogt (2014), The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day, Earth Planet. Sci. Lett., doi:10.1016/j.epsl.2014.02.020.


(2023) Plate tectonics and the search for life: Geophysical constraints on the exploration of Europa. Department of Earth, DEEPS Geophysics Seminar, Brown University.

(2023) The Icy Shells of Europa and Enceladus: Probabilistic Requirements Definition. NASA Cryobot Workshop, California Institute of Technology.

(2023) Europa Clipper and Beyond: Geophysical constraints on the search for life at Europa. Astrobiology Lecture, University of Southern California.

(2022) Powering Fire and Ice with Iron: The role of metal core dissipation in the Galilean satellites. Geology and Geophysics of Active Satellites and Small Bodies, AGU Fall Meeting

(2022) Core activity in the Galilean satellites. NASA Europa Clipper Mission Geodesy Focus Group

(2022) Going Under the Ice with Dr. Samuel Howell. Universe Today.

(2022) Exploring Europa with the Europa Clipper Mission. Princeton Center for Theoretical Science.

(2022) Panelist: Habitability and Astrobiology. Princeton Center for Theoretical Science.

(2022) Plate Tectonics and the Search for Life. University of Hawaiʻi at Mānoa, School of Ocean and Earth Science and Technology (SOEST).

(2021) Early Career Panelist, 12th annual Lunar and Small Bodies Graduate Forum (LunGradCon). (2020) The Likely Thickness of Europa’s Icy Shell, Europlanet Science Congress (EPSC).

(2020) Linking ice shell deformation to Europa's habitability. Earth Life Science Institute (ELSI) Second Annual Winter School on Aquaplanetology (Aso, Japan).

(2020) The Exploration of Europa, an Alien Ocean World, University of Hawaiʻi at Mānoa Department of Earth Sciences.

(2019) Exploring Europa: A dynamic ocean world. Boise State / KBSX. Astronomy Lecture Series.

(2019) Ocean world ice shell transport processes. NASA Astrobiology Institute Titan Meeting (JPL).

(2018) Facilitating ocean-surface exchange through ice shell tectonics. NASA Astrobiology Institute Icy Worlds Meeting (Monrovia, CA)

(2018) Simulating tectonic windows into ocean worlds, California Institute of Technology, Dix Planetary Science Seminar.

(2018) Extensional Terrains: Tectonic windows into ocean worlds. University of California, Los Angeles Earth, Planetary, and Space Sciences Colloquium.


Europa Clipper