University of Minnesota
School of Physics & Astronomy
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Robert Pepin

Professor (Minnesota Institute for Astrophysics)

SHEPLAB 421 (office), 624-0819
SHEPLAB 214 (lab), 624-6001
pepin001 @


Sigma Xi National Lecturer, 1970-71; NASA Medal for Exceptional Scientific Achievement, 1971; Director, Lunar Science Institute, Houston, 1974-77, Fellow of the Meteoritical Society, 1980; Director, Institute of Technology Honors Program, 1989-2009; Fellow of the American Geophysical Union, 1993; Morse-Alumni Award for Outstanding Contributions to Undergraduate Education, 2000; George Taylor Distinguished Service Award, 2001; Asteroid “robertpepin”, 2002; Fellow of the Geochemical Society and European Association for Geochemistry, 2007.

Co-Investigator, NASA Genesis Solar Wind Sample Return Mission, 1993-2010; Science adviser, NASA Stardust Comet Sample Return Mission, 1994-present; Co-Investigator, NASA Curiosity Rover Mission to Mars 2002- present. 1974-2008: Member or chair of 12 NASA Committees and Panels; Associate Editor of two journals; Editor of 4 books; Editor or Co-Editor of 10 Conference Proceedings volumes; Member or chair of 19 conference organizing and program committees.

About My Work

Origin and early history of volatile elements and compounds in the solar system as revealed by mass spectrometer measurements of noble gases and nitrogen in meteorites, lunar samples, interplanetary dust particles, and comets. Areas of particular interest include the composition of the primordial solar nebula, isotopic signatures of nucleosynthesis in primitive meteorites, the compositional history of solar wind and flares over the past 4+ billion years, and the origin and evolution of volatiles in the interiors and atmospheres of Earth, Mars and Venus.

Selected Publications

C. R. Webster et al., Isotope ratios of H, C, and O in CO2 and H2O of the Martian atmosphere., Science 341, 260-263 (2013)

S. K. Atreya et al. , Primordial argon isotope fractionation in the atmosphere of Mars measured by the SAM instrument on Curiosity and implications for atmospheric loss., Geophys. Res. Lett. 40, 1-5, (2013).

M. H. Wong et al. , Isotopes of nitrogen on Mars: Atmospheric measurements by Curiosity’s mass spectrometer., Geophys. Res. Lett. 40, 6033-6037 (2013)

R. O. Pepin, R. L. Palma, R. D. Gehrz, and S. Starrfield, Presolar grains from novae: Evidence from neon and helium isotopes in comet dust collections., ApJ 742:86 (15pp), (2011).

R. O. Pepin, D. J. Schlutter, R. H. Becker, and D. B. Reisenfeld, Helium, neon, and argon composition of the solar wind as recorded in gold and other Genesis collector materials., Geochim. Cosmochim. Acta 89, 62-80, (2012)

B. Marty, R. L. Palma, R. O. Pepin, L. Zimmermann, D. J. Schlutter, P. G. Burnard, A. J. Westphal, C. J. Snead, S. Bajt, R. H. Becker, and J. Simones , Helium and neon abundances and isotopic compositions in cometary matter., Science 319, 75-78 (2008).

P. R. Mahaffy et al. , Abundance and isotopic composition of gases in the Martian atmosphere from the Curiosity rover., Science 341, 263-266 (2013).


Ph.D. Physics, University of California, Berkeley, 1964.
A.B. Physics, Harvard College, 1956.