Samuel P. Kounaves

Samuel P. Kounaves

Adjunct Professor, Department of Earth and Ocean Sciences, Tufts University
Visiting Professor, Department of Earth Science & Engineering, Imperial College London, UK
Research Affiliate, NASA-Jet Propulsion Laboratory, Pasadena, CA
Scientific Advisor, Centre of Astronomy & Astrophysics, Technical University Berlin, Germany
Pearson Chemical Laboratory
62 Talbot Avenue, Medford, MA


  • Postdoctoral Fellow, Harvard University, Cambridge, MA (James Young), 1987-88
  • Postdoctoral Research Associate, S.U.N.Y. at Buffalo, NY (Janet Osteryoung), 1985-86
  • PhD (D.Sc.), Université de Genève, Geneva, Switzerland (Jacques Buffle), 1985
  • BA, 1975, M.S., California State University at San Diego/SDSU, CA (Alberto Zirino), 1978

Research Interests

In-situ Planetary and Extreme Biogeochemical Analysis The Kounaves group research is aimed at unraveling fundamental questions in planetary science using modern in-situ analytical systems designed to study the biogeochemistry of extreme environments, where no one has gone before. As Co-I and Lead Scientist for the Wet Chemistry Lab (WCL) onboard NASA's Phoenix Mars Lander, Kounaves and his group performed the first wet chemical analysis of the martian soil using an array of electrochemical sensors. The experiments revealed an alkaline soil containing a variety of soluble minerals, but most surprising was the discovery of almost 1% perchlorate (ClO4-). Its discovery has wide ranging implications and has altered the way we view the chemistry of Mars and its potential to support life.

The presence of perchlorate as Ca(ClO4)2 suggests that Mars' surface may have been severely arid for at least the past ~600 million years. The ClO4- may also be responsible for brines due to its depression of the H2O freezing point to -78ºC, the control of planet-wide soil and atmospheric water content, and the dificulty of instruments to detect organics on Mars (VL/GCMS; Phx/TEGA; & MSL/SAM). It could also act as an electron doner/energy source for any indigenous subsurface microbes, and is both good & bad for human explorers (can provide energy, fuel, and oxygen, but is human health hazard). The group's recent discovery, that ClO4- may form on any Cl-bearing mineral surface that is exposed to UV and that the process generates intermediary oxychlorines and highly oxidizing radicals, has implications not only for the production of ClO4- and the alteration of organics on Mars, but also on Earth and perhaps throughout the solar system and beyond.

The discovery of ClO4- on Mars led the group to investigate the same possibility in Antarctica's McMurdo Dry Valleys. The study provided the first unambiguous discovery and clear evidence of the ubiquitous natural formation of perchlorate on Earth, with accumulation in arid environments and global atmospheric production. The discovery also suggests the hypothesis that the perchlorate reducing bacteria and arachea may be a remnant of a significant pre-oxygen Earth perchlorate ecosystem. The group has also recently confirmed ClO4-, ClO3-, and NO3-, in the Mars meteorites EETA79001 & Tissint, and also in lunar and chondrite meteorites.

In addition to the current investigations exploring Mars' geochemistry and its potential for supporting past or present microbial life in surface or subsurface environments, their research (funded by NASA and NSF) includes understanding the geochemical and environmental history as recorded by the chemistry of planetary surface materials, and the geobiochemistry in extreme environments on Earth in places such as the McMurdo and other Antarctica Dry Valleys, Death Valley, the Tindouf Basin (Morocco), the Atacama Desert (Chile), and deep-ocean thermal vents.

Most recently they have been funded by NASA COLDTech and ICEE2 grants to develop a chemical sensor array to study the geochemistry, subglacial ocean chemistry, and habitability of Saturn's moon Enceladus by analysis of the ejected plume material.

Selected Honors and Awards

ACS-Kavli Award for Innovations in Chemistry (2019)
NASA Exceptional Achievement Award for New Opportunities to ELSHA Team (2019)
Fellow, The Geological Society (2016)
Fellow, Royal Society of Chemistry (2015)
Fellow, American Association for the Advancement of Science (2013)
NASA Achievement Award for Outstanding Performance in the Planning and Execution of the Science for the Phoenix Mars Mission (2009)
NASA Achievement Award for Development and Operation of the Phoenix Spacecraft Leading to the First Landing in the Martian Arctic (2009)
Swigert Award for Space Exploration as member of the Phoenix Mars Mission Team (2009)
Massachusetts Columbus Quincentennial Exploration & Discovery Award for Innovative Achievement (2008)
K. D. Wood Colloquium Lecture Award, Aerospace Sciences, University of Colorado (2006)
Arno Heyn Memorial Award, American Chemical Society, NE Section (2006)
Tufts Junior Faculty Fellowship Award (1990)
National Research Council Fellowship (1986)

Selected Publications and Presentations

Indigenous Organic-Oxidized Fluid Interactions in the Tissint Mars Meteorite, E. A. Jaramillo (Oberlin), S. H. Royle, M. W. Claire, S. P. Kounaves, and M. A. Sephton, Geophys. Res. Lett. 2019, 46, 3090-3098, doi:10.1029/2018GL081335

A Transitory Microbial Habitat in the Hyperarid Atacama Desert, D. Schulze-Makuch, D. Wagner, S. P. Kounaves, et al., PNAS, 2018, 115, 2670-2675, doi:10.1073/pnas.1714341115

Effect of hydration state of Martian perchlorate salts on their decomposition temperatures during thermal extraction, S. H. Royle, W. Montgomery, S. P. Kounaves and M. A. Sephton, J. Geophys. Res., 2017, 122, 2793-2802, doi:10.1002/2017JE005381

Deliquescence-Induced Wetting and RSL-Like Darkening of a Mars Analogue Soil Containing Perchlorate and Chloride Salts, J. Heinz, D. Schulze-Makuch, and S. P. Kounaves, Geophys. Res. Lett., 2016, 43, 4880–4884, doi:10.1002/2016GL068919

The Origins of Perchlorate in the Martian Soil, B. L. Carrier and S. P. Kounaves, Geophys. Res. Lett., 2015, 42, 3739-3745. doi:10.1002/2015GL064290

Identification of the Perchlorate Parent Salts at the Phoenix Mars Landing Site and Possible Implications, S. P. Kounaves, N. A. Chaniotakis, V. F. Chevrier, B. L. Carrier, K. E. Folds, V. M. Hansen, K. M. McElhoney, G. D. O'Neil, and A. W. Weber, Icarus, 2014, 232, 226-231. doi:10.1016/j.icarus.2014.01.016

Evidence of Martian Perchlorate, Chlorate, and Nitrate in Mars Meteorite EETA79001: Implications for Oxidants and Organics, S. P. Kounaves, B. L. Carrier, G. D. O'Neil, S. T. Stroble, and M. W. Clair, Icarus, 2014, 229, 206-213. doi:10.1016/j.icarus.2013.11.012

An Electrochemically Based Total Organic Carbon Analyzer for Planetary and Terrestrial On-Site Applications, S. T. Stroble and S. P. Kounaves, Anal. Chem., 2012, 84, 6271–6276. doi:10.1021/ac301704m

Effects of Extreme Cold and Aridity on Soils and Habitability: McMurdo Dry Valleys as an Analog for the Mars Phoenix Landing Site, L. K. Tamppari, R. M. Anderson, P. D. Archer Jr., S. Douglas, S. P. Kounaves, C. P. McKay, D. W. Ming, Q. Moore, J. E. Quinn, P. H. Smith, S. Stroble, A. P. Zent, Antarctic Science, 2012, 24, 211-228. doi:10.1017/S0954102011000800

A Perchlorate Brine Lubricated Deformable Ice Bed Flow of the North Polar Cap of Mars: Possible mechanism for water table recharging, D. Fisher, M. H. Hecht, S. P. Kounaves, and D. C. Catling, J. Geophys. Res., 2010, 115, E00E12, doi:10.1029/2009JE003405 (Our hypothesis presented in this paper of subglacial liquid water has now been confirmed by Orosei et al., Science, 2018).

Soluble Sulfate in the Martian Soil at the Phoenix Landing Site, S. P. Kounaves, M. H. Hecht, J. Kapit, R. C. Quinn, D. C. Catling, B. C. Clark, D. W. Ming, K. Gospodinova, P. Hredzak, K. McElhoney, and J. Shusterman, Geophys. Res. Lett., 2010, 37, L09201. doi:10.1029/2010GL042613

Discovery of Natural Perchlorate in the Antarctic Dry Valleys and its Global Implications, S. P. Kounaves, S. T. Stroble, R. M. Anderson, Q. Moore, D. C. Catling, S. Douglas, C. P. McKay, D. W. Ming, P. H. Smith, L. K. Tamppari, A. P. Zent, Environ. Sci. Technol., 2010, 44, 2360-64. doi:10.1021/es9033606

Wet Chemistry Experiments on the 2007 Phoenix Mars Scout Lander: Data Analysis and Results, S. P. Kounaves, M. H. Hecht, J. Kapit, K. Gospodinova, L. DeFlores, R. C. Quinn, W. V. Boynton, B. C. Clark, D. C. Catling, P. Hredzak, D. W. Ming, Q. Moore, J. Shusterman, S. Stroble, S. J. West, and S. M. Young,. J. Geophys. Res., 2010, 115, E00E10. doi:10.1029/2009JE003424

Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site, M. H. Hecht, S. P. Kounaves, R. C. Quinn, S. J. West, S. M. M. Young, D. W. Ming, D. C. Catling, B. C. Clark, W. V. Boynton, J. Hoffman, L. P. DeFlores, K. Gospodinova, J. Kapit, and P. H. Smith Science, 2009, 325, 64-67. doi:10.1126/science.1172466

Evidence for Calcium Carbonate at the Mars Phoenix Landing Site, W. V. Boynton, D. W. Ming, S. P. Kounaves, et al., Science, 2009, 325, 61-64. doi:10.1126/science.1172768

H2O at the Phoenix Landing Site, P. H. Smith, L. K. Tamppari, R. E. Arvidson, D. Bass, D. Blaney, W. V. Boynton, A. Carswell, D. C. Catling, B. C. Clark, T. Duck, E. DeJong, D. Fisher, W. Goetz, H. P. Gunnlaugsson, M. H. Hecht, V. Hipkin, J. Hoffman, S. F. Hviid, H. U. Keller, S. P. Kounaves, et al., Science, 2009, 325, 58-61. doi:10.1126/science.1172339