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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 in the Planetary Interiors and Geophysics Group at JPL, where he primarily works on 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 Project, which will conduct an analogue science mission to Europa by accessing a subglacial lake in the Juneau Icefield with a planetary “cryobot,” and is the Deputy Principal Investigator and Lead Scientist for JPL's PRIME, a technology concept to explore the interior oceans of Ocean Worlds, as well as derivative proposals and technologies. Dr. Howell is also Co-Investigator and the Lead Scientist for NASA’s SWIM technology concept, which looks further into the future at potential avenues to explore alien oceans using swarm microrobotics.

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, focused on the simple understanding that observable features are fingerprints of the planetary processes at depth: failure, flow, melting, mixing, and material transport. 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.

Samuel’s current and proposed research concerns the mechanisms and timescales of ocean world material mixing and evolution, as well as the exchange of materials between interior oceans and outer ice shells. His postdoctoral research linking tectonic processes on Europa and Ganymede to the surface exposure of fossilized ocean material received NASA-wide coverage and the 2017 JPL Outstanding Postdoctoral Research Award in Planetary Science and Astrobiology. Subsequent studies of Ocean Worlds and their exploration technologies that Samuel has led or supported have been reported internationally.

In his spare time, he has climbed Mount Kilimanjaro, completed triathlons and marathons, and serendipitously met his wife, Marissa, an expert on the surfaces of icy moons and exploration of the solar system.


PhD Geology and Geophysics, University of Hawaiʻi at Mānoa, Dec. 2017

M.S. Geology and Geophysics, University of Hawaiʻi at Mānoa, Aug. 2013

B.S. Engineering Physics, Rose-Hulman Institute of Technology, May, 2010

Professional Experience

  • Jet Propulsion Laboratory (2017-present)
    • Research Scientist, Ocean Worlds, Planetary Interiors and Geophysics Group (2019 - Present)
    • Project Staff Scientist, Europa Clipper (2019 – Present)
    • JPL Postdoctoral Researcher, Ocean Worlds Group (2019)
    • Europa Clipper Science Team Postdoctoral Affiliate in Project Science (2017-2019)
  • California Institute of Technology, Postdoctoral Scholar, JPL Planetary Chemistry and Astrobiology Group (2017 - 2019)
  • University of Hawai’i at Mānoa  (2010-2016)
    • Research Assistant (2010-2016)
    • Teaching Assistant (2011)

Selected Projects

  • PI (2022-2025) ORCAA: Ocean Worlds Reconnaissance of Astrobiological Analogues, PSTAR.
  • 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/Collaborator (2019-2023) Search for Life Using Submersible Heated Drill (SLUSH), Scientific Exploration Subsurface Access Mechanism for Europa.
  • 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.

Professional Activities

  • (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 Principal 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

Selected Awards

  • (2021) JPL Voyager Award for leadership of the Europa Clipper Lecture Series
  • (2021) JPL Team Award for contribution to the Decadal Survey in Planetary Science and Astrobiology
  • (2017) JPL 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 (2022, in production). 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.

Lesage, E., H. Massol, S. Howell, F, Schmidt. (2022, in press). Viscoelastic deformation of freezing cryomagma reservoirs: Application to Europa. The Planetary Science Journal.

Pappalardo et al., incl. S. Howell (2022, in prod.). Ganymede’s Geology, in Ganymede, Cambridge Press.

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., E. J. Leonard (2021, in press). Ocean Worlds: Interior Processes and Physical Environments, Handbook of Space Resources, Springer Publishing.

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.

Olive, J.-A., M. D. Behn, G. Ito, W. R. Buck, J. Escartín, S. Howell (2015), Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply, Science, doi:10.1126/science.aad0715.

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.


  • (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) Europa’s habitability: Dynamic ice processes and future Ocean World exploration. Alternative Earths Astrobiology Seminar, University of California, Riverside, Department of Earth and Planetary 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