University of Minnesota
School of Physics & Astronomy
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Robert Pepin

Professor, Emeritus

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, Genesis Solar Wind Sample Return Discovery Mission, 1993-present; Science adviser and Member, Preliminary Examination Team, Stardust Comet Sample Return Discovery Mission, 1994-present; Co-Investigator, SAM Discovery 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

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 (2008)

R. O. Pepin, “Atmospheres on the Terrestrial Planets: Clues to Origin and Evolution,”, Earth Planet. Sci. Lett. (2006)

R. O. Pepin and D. Porcelli, “Xenon Isotope Systematics, Giant Impacts, and Mantle Degassing on the Early Earth”,, Earth Planet. Sci. Lett. (2006)

R. Pepin, On noble gas processing in the solar accretion disk, Space Science Reviews 106, 211-230 (2003).

R. Pepin, Irradiation records in regolith materials, II: Solar wind and solar energetic particle components in helium, neon, and argon extracted from single lunar mineral grains and from the Kapoeta howardite b, Geochimica et Cosmochimica Acta 66, 2929-2958 (2002).

R. Pepin, Origin of noble gases in the terrestrial planets, Reviews in Mineralogy and Geochemistry 47, 191-246 (2002).

R. Pepin, Noble gases in interplanetary dust particles, II: Excess helium-3 in cluster particles and modeling constraints on interplanetary dust particle exposures to cosmic ray irradiation, Meteoritics and Planetary Science 36, 1515-1534 (2001).


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