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Dr. Steve Clifford

Senior Scientist

Currently resides in Houston, TX
sclifford [at]
Areas of Expertise
Earth, Icy satellites, Mars | Mars Express (ESA), Rosetta | Mission Co-Investigator, Mission science team | Field Work, Geology, Geomorphology, Numerical modeling, Radar, Remote sensing, Thermal modeling

Research Interests

  • Primary area of research: the nature, evolution and geophysical investigation of planetary volatiles, with a special emphasis on water on Mars.  
  • Work has included research on the factors and processes affecting the distribution, stability and transport of H2O in the Martian near- and deep-subsurface; glacial flow and polar evolution; the formation and stability of gas hydrates; large-scale groundwater flow; the hydrologic consequences of impact cratering; the existence and fate of an early ocean; as well as other aspects of the long-term evolution of the Martian hydrosphere.  

Professional History

Professional Employment:

  • Senior Research Scientist (2018-present), Planetary Science Institute, Tucson, AZ.
  • Senior Staff Scientist (2006-2018), Lunar and Planetary Institute/USRA, LPI Post-Doctoral Fellow (1984-1985); LPI Staff Scientist (1985 1993); LPI Visiting Scientist (1993-1997); and LPI Staff Scientist (1997 2006).
  • Invited Professor:
    • DES (Interactions et Dynamique des Environnements de Surface (IDES), Université Paris Sud, Orsay, France (analysis of Mars orbital radar and imagery data to assess the evidence for a former ocean in the northern plains) and Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Guyancourt, France (development of the WISDOM ground-penetrating radar for the 2020 ESA ExoMars Rover mission), (2 months total, 2012).
    • Laboratoire de Planétologie de Grenoble, Université Joseph Fourier (2 months, 2010), Grenoble, France. Orbital radar sounding investigations of the geology and subsurface hydrology of Mars.
    • Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) (1 month, 2010), Guyancourt, France. Radar field investigations of Mars analog environments and numerical simulations of HF and VHF radar performance on Mars.
    • Institut de Physique du Globe de Paris (IPGP), Department of Space and Planetary Geophysics, (3 months, 2008), Paris, France. Research on GPR and other geophysical investigations of planetary environments.


  • Ph.D., Astronomy, University of Massachusetts, 1984.
  • M.S., Physics, University of Massachusetts, 1980.
  • B.A., Math/Physics, Windham College, 1975.

 Active Spacecraft Mission & Instrument Involvement:

  • Science PI (2017 – present), An Ultra-Wideband Radar for Measurements of Martian Polar Layered Deposits and Seasonal Ice, submitted to NASA’s Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Program.
  • Deputy Science Team Leader (2006 – present), WISDOM VHF ground penetrating radar (V. Ciarletti, PI) selected for ESA’s 2020 ExoMars Rover mission.
  • Science Team Member (2006 – present), CONSERT HF radar on ESA’s Rosetta comet mission (W. Kofman, PI).
  • U. S. Participating Scientist (2003 – present), MARSIS orbital radar sounder (G. Picardi, PI; J.J. Plautt, U.S. Co-PI), ESA’s Mars Express mission.

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