Skip Navigation

Robert Pappalardo

Photo of Robert Pappalardo


4800 Oak Grove Drive
M/S 321-560

Pasadena, CA 91109





Curriculum Vitae:

Click here


Click here

Member of:

Science Division

Europa Mission Project Scientist


Robert Pappalardo is a Project Scientist, JPL Fellow, and Senior Research Scientist in the Planetary Science Section, Science Division.

In 1986 he received his B.A. in Geological Sciences from Cornell University, and in 1994 he obtained his Ph.D. in Geology from Arizona State University. As an affiliate member of the Galileo Imaging Team while a researcher at Brown University, he worked to plan many of the Galileo observations of Jupiter's icy Galilean satellites. From 2001-2006, he was an Assistant Professor of Planetary Sciences in the Astrophysical and Planetary Sciences Department of the University of Colorado at Boulder, and he continues to mentor graduate student and postdoctoral researchers. Science communications being a priority, he has worked with a variety of organizations to bring the excitement of planetary exploration to the public.


  • Ph.D., Arizona State University, Tempe, AZ; Geology; 1994.
  • B.A., Cornell University, Ithaca, NY; Geological Sciences; 1986.

Professional Experience

  • Jet Propulsion Laboratory (2006-present)
    • Europa Clipper Project Scientist
    • JPL Fellow
    • Senior Research Scientist
  • University of Colorado, Boulder (2001-2006)
    • Assistant Professor - Astrophysical and Planetary Sciences Department & Laboratory for Atmospheric and Planetary Sciences
  • Brown University (1995-2001)
    • Postdoctoral Research Associate in Geological Sciences
  • Arizona State University (1994-1995)
    • Postdoctoral Research Associate in the Department of Geology

Selected Professional Service

  • Study Scientist for Europa Mission concept (2008-Present)
  • Project Scientist for Cassini Equinox Mission (2008-2010)
  • Member of National Research Council's Space Studies Board (2008-Present)
  • Co-Chair, Committee on the Origins and Evolution of Life, COEL (2008-2011)
  • Jupiter/Europa International Working Group (2005-2006)
  • NASA Solar System Exploration Strategic Roadmap Committee (2005-2006)
  • NASA Solar System Exploration Subcommittee (SSES) (2004-2005)
  • Jupiter Icy Moons Orbiter (JIMO) Science Definition Team (2003-2004)
  • Associate Editor, Geophysical Research Letters (2002-2004)
  • Steering Group Member and Vice-Chair of Large Satellites Panel, Solar System Exploration Strategy Committee (Planetary Science Decadal Survey) (2001-2002)
  • Committee on Planetary and Lunar Exploration (COMPLEX) (1999-2002)

Community Service

  • Member, Scientific Organizing Committee, Workshop on the Origins and Habitability of the Galilean Moons, 2023.
  • Scientific Event Deputy Organizer, Ocean Worlds: Europa, Enceladus, Titan, and Beyond, 42nd COSPAR Scientific Assembly, 2018.
  • Member, Scientific Organizing Committee, Enceladus and the Icy Moons of Saturn, 2016.
  • Committee Member, Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS), 2011–2014.
  • Member, Space Studies Board of the National Academy of Sciences, 2008–2014.
  • Co-Chair, Committee on the Origins and Evolution of Life, COEL (2008–2011)

Research Interests

Pappalardo's research focuses on processes that have shaped the icy satellites of the outer solar system, especially Europa and the role of its probable subsurface ocean. Europa research includes the possibility that solid-state convection has played an important role in the satellite's history, investigation of regions of separation and spreading of the satellite's icy lithosphere, and implications of surface geology for lithospheric properties and the existence of a liquid water ocean beneath the icy surface. Additional recent research involves the nature, origin, and evolution of bright grooved terrain on Jupiter's moon Ganymede, and the geological history of Saturn's moons Enceladus and Titan. Recent research relates to the relative roles of tectonics, icy volcanism, and mass wasting in shaping icy satellite surfaces.

Selected Awards

  • JPL Magellan Award (2016, 2020)
  • NASA Exceptional Service Medal (2011)

Selected Publications

  1. Mills, M.M., R. T. Pappalardo, M. P. Panning, Erin J. Leonard, Samuel M. Howell, Moonquake-triggered mass wasting processes on icy satellites. Icarus, 399, 115534, 2023.
  2. Hay, H. C. F. C., I. Fenty, R.T. Pappalardo, and Y. Nakayama, Turbulent drag at the ice-ocean interface of Europa in simulations of rotating convection: Implications for nonsynchronous rotation of the ice shell. J. Geophys. Res. – Planets, 128, e2022JE007648, 2023.
  3. Burkhard, L. M. L., B. R. Smith-Konter, S. A. Fagents, M. E. Cameron, G. C. Collins, and R. T. Pappalardo, Strike-slip faulting on Titan: Modeling tidal stresses and shear failure conditions due to pore fluid. Icarus, 371, 114700, 2022.
  4. Hay, H. C. F. C., I. Matsuyama, and R. T. Pappalardo. The high-frequency tidal response of ocean worlds: Application to Europa and Ganymede. J. Geophys. Res. – Planets, 127, e2021JE007064, 2022.
  5. Leonard, E. J., S. Howell, A. Mills, D. A. Senske, D. A. Patthoff, H. Hay, R. T. Pappalardo. Finding order in chaos: Quantitative predictors of chaos terrain morphology on Europa. Geophys. Res. Lett., 49(8),, 2022.
  6. Patthoff, D. A., R. T. Pappalardo, M. Golombek, H. Chilton, E. Crow-Willard, and P. C. Thomas. Thrust faulting as the origin of dorsa in the trailing hemisphere of Enceladus. Icarus, 375, 114815, 2022.
  7. Leonard, E., A. Yin, and R. Pappalardo, Forming relic cratered blocks: Left-lateral shear on Enceladus inferred from ice-shell deformation in the leading hemisphere. J. Geophys. Res. – Planets, 126, e2020JE006499, 2021.
  8. Cameron, M. E., B. R. Smith-Konter, G. C. Collins, D. A. Patthoff, and R. T. Pappalardo, Ganymede then and now: How past eccentricity may have altered tidally driven Coulomb failure. Journal Geophys. Res. - Planets, 125, e2019JE005995,, 2020.
  9. Howell, S. M. and R. T. Pappalardo, NASA's Europa Clipper—A mission to a potentially habitable ocean world. Nature Comms., 11:1311,, 2020.
  10. Leonard, E., A. Yin, and R. T. Pappalardo, Ridged plains on Europa reveal a compressive past. Icarus, 343, 113709, 2020.
  11. Howell, S. M. and R. T. Pappalardo. Can Earth-like plate tectonics occur in ocean world ice shells? Icarus, 322, 69-79, 2019.
  12. Howell, S. M. and R. T. Pappalardo. Band formation and ocean-surface interaction on Europa and Ganymede. ‎Geophys. Res. Lett., 45, 4701-4709, 2018.
  13. Leonard, E. J., R. T. Pappalardo, and A. Yin. Analysis of very-high-resolution Galileo images and implications for resurfacing mechanisms on Europa. Icarus, 312, 100-120, 2018.
  14. Patterson, G. W., S. A. Kattenhorn, P. Helfenstein, G. C. Collins, and R. T. Pappalardo. The Geology of Enceladus. In: Enceladus and the Icy Moons of Saturn (P. M. Schenk et al., eds.), pp. 95-125. Univ. of Arizona, Tucson, 2018.
  15. Vance, S. D., K. P. Hand, and R. T. Pappalardo. Geophysical controls of chemical disequilibria in Europa, Geophys. Res. Lett., 43, 4871-4879, doi:10.1002/2016GL068547, 2016.
  16. Crow-Willard, E. N. and R. T. Pappalardo. Structural mapping of Enceladus and implications for formation of tectonized regions. J. Geophys. Res. Planets, 120, 928-950, 2015.
  17. Yin, A. and R. T. Pappalardo, Gravitational spreading, bookshelf faulting, and tectonic evolution of the South Polar Terrain of Enceladus. Icarus, 260, 409–439, 2015.
  18. Sims, D., D. Wyrick, D. Ferrill, A. Morris, G. Collins, R. Pappalardo, and S. Colton. Physical models of grooved terrain tectonics on Ganymede. Geophys. Res. Lett., 41, doi:10.1002/2014GL060359, 2014.
  19. Besserer, J., F. Nimmo, J. H. Roberts, and R. T. Pappalardo. Convection-driven compaction as a possible origin of Enceladus's long wavelength topography. Geophys. Res. Lett, doi:10.1002/jgre.20079, 2013.
  20. Gleeson, D. F., Pappalardo, R. T., M.S. Anderson, S. E. Grasby, R.E. Mielke, K.E. Wright, and A.S. Templeton. Biosignature detection at an Arctic analog to Europa. Astrobiology, 12, 1-16, 2012.
  21. Gleeson, D.F., C. Williamson, S.E. Grasby, J. Spear, R.T. Pappalardo, and A.S. Templeton. Low temperature S0 biomineralization at a supraglacial spring system in the Canadian High Arctic. Geobiology, 9, 360-375, 2011.
  22. Moore, J.M., and R.T. Pappalardo. Titan: An exogenic world? Icarus, 212, 790-806.
  23. Olgin, J. G., B. R. Smith-Konter, and R. T. Pappalardo. The limits of Enceladus's ice shell thickness from tidally driven tiger stripe shear failure. Geophys. Res. Lett., 38, L02201, doi:10.1029/2010GL044950.
  24. Pappalardo. R. T. Seeking Europa's ocean. In Galileo's Medicean Moons: Their Impact on 400 Years of Discovery, Proceedings IAU Symposium No. 269 (C. Barbieri et al., eds.), pp. 101-114, 2010.
  25. Pappalardo. R. T. What we don't know about Europa. In Challenging the Paradigm: The Legacy of Galileo (C. Zuffada et al., eds.), California Institute of Technology, Pasadena, pp. 33-53, 2009.
  26. Collins, G. C., W.B. McKinnon, J.M. Moore, F. Nimmo, R.T. Pappalardo, L.M. Prockter, and P.M. Schenk. Tectonics of the outer planet satellites. In PlanetaryTectonics (T. Watters and R. Schultz, eds.), Cambridge Univ. Press, pp. 264-350, 2010.
  27. Gleeson, D., R. T. Pappalardo, S. Grasby, M. Anderson, R. Casta&#241n&#241o, S. Chien, T. Doggett, L. Mandrake, and K. Wagstaff. Characterization of a sulfur-rich Arctic spring site and field analog to Europa using hyperspectral data. Remote Sensing Environ., 114, 1297-1311, 2010.
  28. Pappalardo, R.T., W.B. McKinnon, and K.K. Khurana (eds.). Europa, Univ. Arizona Press, Tucson, 727 pp., 2009.
  29. Wahr, J., Z.A. Selvans, M.C. Mullen, A.C. Barr, G.C. Collins, M.M. Selvans, and R.T. Pappalardo. Modeling stresses on satellites due to nonsynchronous rotation and orbital eccentricity using gravitational potential theory. Icarus, 200, 188-206, 2009.
  30. Smith-Konter, B., and R.T. Pappalardo. Tidally driven stress accumulation and shear failure of Enceladus's tiger stripes. Icarus, 198, 435-451, 2008.
  31. Collins, G. C., W.B. McKinnon, J.M. Moore, F. Nimmo, R.T. Pappalardo, L.M. Prockter, and P.M. Schenk. Tectonics of the outer planet satellites, In Planetary Tectonics (T. Watters and R. Schultz, eds.), Cambridge Univ. Press, in press.
  32. Wahr, J., Z.A. Selvans, M.C. Mullen, A.C. Barr, G.C. Collins, M.M. Selvans, and R.T. Pappalardo. Modeling stresses on satellites due to non-synchronous rotation and orbital eccentricity using gravitational potential theory. Icarus, submitted.
  33. Khurana, K.K., R.T. Pappalardo, N. Murphy, and T. Denk. The origin of Ganymede's polar caps. Icarus, 191, 193-202, 2007.
  34. Nimmo, F., J.R Spencer, R.T. Pappalardo, and M.E. Mullen. A shear-heating mechanism for the generation of vapour plumes and high heat fluxes on Saturn's moon Enceladus. Nature, 447, 289-291, 2007.
  35. Nimmo, F. and R. T. Pappalardo. Diapir-induced reorientation of Enceladus. Nature, 441, 614-616, 2006.


Europa Clipper