Robert Pappalardo is a Senior Research Scientist in the Planetary Science Section, Science Division.

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 the 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, specifically the style of tectonism and implications for the satellite's geological history. Also, he is investigating the geological implications of geyser-like activity on Saturn's moon Enceladus and of processes that shape the surface of Saturn's moon Titan.

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 researchers. Along the way, he has worked with various science museums and organizations to bring the excitement of astronomy and planetary exploration to the public.

• Jet Propulsion Laboratory (2006-present)
  • 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 Univerisity (1994-1995)
  • Postdoctoral Research Associate in the Department of Geology

• 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)

• NASA Exceptional Service Medal (2011)
• NASA Group Achievement Award - Cassini Solstice Pre-Integration Team (2011)

1. Moore, J.M., and R.T. Pappalardo. Titan: An exogenic world? Icarus, 212, 790-806.
2. 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.
3. *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.
4. *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.
5. 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, pp. 264-350, 2010.
6. Gleeson, D., R. T. Pappalardo, S. Grasby, M. Anderson, R. Castañnño, 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.
7. Pappalardo, R.T., W.B. McKinnon, and K.K. Khurana (eds.). Europa, Univ. Arizona Press, Tucson, 727 pp., 2009.
8. 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.
9. Smith-Konter, B., and R.T. Pappalardo. Tidally driven stress accumulation and shear failure of Enceladus's tiger stripes. Icarus, 198, 435-451, 2008.
10. 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.
11. 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.
12. Khurana, K.K., R.T. Pappalardo, N. Murphy, and T. Denk. The origin of Ganymede's polar caps. Icarus, 191, 193-202, 2007.
13. Pappalardo, R.T. Oceans in the outer Solar System - And not a drop to drink. Planetary Report, XXVII (4), 12-17, 2007.
14. Prockter, L.M., and R.T. Pappalardo. Europa. In Encyclopedia of the Solar System, 2nd ed. (L McFadden et al., eds.), Academic Press, pp. 431-448, 2007.
15. 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.
16. Nimmo, F. and R. T. Pappalardo. Diapir-induced reorientation of Enceladus. Nature, 441, 614-616, 2006.
17. Patterson, G. W., J. W. Head, and R. T. Pappalardo. Plate motion on Europa and nonrigid behavior of the icy lithosphere: The Castalia Macula region. J. Struct. Geol., in press.
18. Barr, A. C. and R. T. Pappalardo. Onset of convection in ice I with composite Newtonian and non-Newtonian Rheology: Application to the icy Galilean satellites. J. Geophys. Res., 110, E12005, doi:10.1029/2004JE002371, 2005.
19. Lee, S., R. T. Pappalardo, and N. C. Makris, Mechanics of tidally driven fractures in Europa's ice shell. Icarus, 177, 367-379, 2005.
20. Pappalardo, R. T. and G. C. Collins. Extensional tectonics on Ganymede as recorded by strained craters. J. Struct. Geol., 27, 827-838, 2005.
21. Prockter, L. M., R. T. Pappalardo, and F. Nimmo. A Shear heating origin for ridges on Triton. Geophys. Res. Lett., 32, L14202, doi:10.1029/2005GL022832, 2005.
22. Stempel, M. M., A. C. Barr, and R. T. Pappalardo, Model constraints on the opening rates of bands on Europa. Icarus, 177, 297-304, 2005.
23. Barr, A. C., S. Zhong, and R. T. Pappalardo. Convective instability in ice I with non-Newtonian rheology: Application to the Galilean satellites. J. Geophys. Res., 109, E12008, doi:10.1029/2004JE002296, 2004.
24. Greeley, R., C. Chyba, J. W. Head, T. McCord, W. B. McKinnon, and R. T. Pappalardo. Geology of Europa. In Jupiter: The Planet, Satellites & Magnetosphere (F. Bagenal et al., eds.), pp. 329-362, 2004.
25. Nimmo, F. and R. Pappalardo. Furrow flexure and ancient heat flux on Ganymede. Geophys. Res. Lett., 31, L19701, doi:10.1029/2004GL020763, 2004.
26. Pappalardo, R. T. and A. C. Barr. Origin of domes on Europa: The role of thermally induced compositional buoyancy. Geophys. Res. Lett., 31, L01701, doi:10.1029/2003GL019202, 2004.
27. Pappalardo, R.T., G.C. Collins, J.W. Head, P. Helfenstein, T. McCord, J.M. Moore, L.M. Prockter, P.M. Schenk, and J. Spencer. Geology of Ganymede. In Jupiter: The Planet, Satellites & Magnetosphere (F. Bagenal et al., eds.), pp. 363-396, 2004.
28. *Pappalardo, R. T. Jupiter's water worlds. Astronomy, 32(1), 34-41, 2004.
29. Schenk, P.M. and R.T. Pappalardo. Topographic variations in chaos on Europa: Implications for diapiric formation. Geophys. Res. Lett., 31, L16703, doi:10.1029/2004GL019978, 2004.
30. Lee, S., M. Zanolin, A. M. Thode, R. T. Pappalardo, and N. C. Makris. Probing Europa's interior using natural ambient noise. Icarus, 165, 144-167, 2003.
31. Pappalardo, R.T. Ganymede and Callisto. In The New Solar System, 4th ed. (J.K. Beatty, C.C. Peterson, and A.L. Chaikin, eds.). Cambridge, Mass.: Sky Publishing Corp., pp. 263-275, 1999.
32. Pappalardo, R.T., and 31 co-authors. Does Europa have a subsurface ocean? Evaluation of the geological evidence. J. Geophys. Res., 104, 24015-24055, 1999.
33. *Pappalardo, R.T. , J.W. Head, and R. Greeley. The hidden ocean of Europa. Sci. Am., 281, no. 4, 54-63, 1999.
34. Pappalardo, R.T., and 15 co-authors. Grooved terrain on Ganymede: First results from Galileo high-resolution imaging. Icarus, 135, 276-302, 1998.
35. Pappalardo, R.T., J.W. Head, R. Greeley, R.J. Sullivan, C. Pilcher, G. Schubert, W. Moore, M.H. Carr, J.M. Moore, M.J.S. Belton, and D.L. Goldsby. Geological evidence for solid-state convection in Europa's ice shell. Nature, 391, 365-368, 1998.