Vitae

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Professional Appointments

June 2023-present Marie Curie Postdoctoral Fellow , Institute d’Astrophysique Spatiale, University of Paris-Saclay.

August 2022-present Research Scientist, Planetary Science Institute.

August 2020-September 2022 Postdoctoral Fellow, Jet Propulsion Laboratory, Caltech.

Education

2020 Ph.D., Brown University, Earth, Environmental & Planetary Sciences.
- Spatial and temporal variations in the chemistry and mineralogy of mafic lacustrine systems on Earth and Mars. Advisor: Ralph Milliken.
2017 M.Sc., Brown University, Earth, Environmental & Planetary Sciences.
- Spectroscopic analysis of iron cycling in a terrestrial ultramafic lake and its implications for martian sedimentary systems. Advisor: Ralph Milliken.
2013 B.A., Columbia University, Earth Science.
- Extractable organic molecules are an effective thermometer of both naturally and artificially heated fault rocks. Advisors: Pratigya Polissar & Heather Savage.

Research Grants

2023-2026 Mars Data Analysis Program (MDAP), NASA ROSES. Co-I. “Analyses of sulfates in chaos regions on Mars.” ($540,000.)
2023-2025 Marie Sklodowska-Curie Actions research fellowship, European Commission (MSCA-EF). PI. “Spectral diversity within Ryugu.” ($210,000.)
2022-2025 Mars Science Laboratory Participating Scientist Program (MSL-PSP). PI. “Understanding Mg-sulfate distribution, hydration state, and crystallinity in Mt. Sharp.” ($300,000.)
2022 Spontaneous Research and Technology Development Program, Jet Propulsion Laboratory. Co-I. “Novel reaction design to test martian weathering.” ($40,000.)
2022 Data Science Working Group, Jet Propulsion Laboratory. Co-I. “Developing machine learning models to facilitate the untargeted identification and classification of organics in complex mixtures via tandem mass spectrometry.” ($50,000.)
2020-2022 Strategic Research and Technology Development Program, Jet Propulsion Laboratory. Science PI. “Experimental constraints on groundwater driven redox gradients on Mars.” ($300,000.)

Awards and Fellowships

•2022 Seal of Excellence, European Commission Marie Sklodowska-Curie Actions (MSCA-2021-PF).

•2020 Dissertation Fellowship, Brown University.

• 2015, 2017 NASA Group Achievement Award, MSL Science and Operations Team.
• 2015-2018 Presidential Fellowship for 3 years full support, Brown University Graduate School.
• 2013 Walter C. Pitman III Award for excellence in thesis research and presentation, Columbia University.

Lab and Mission Experience

Science Team Member, Hayabusa2. 2023-present
Participating Scientist, Mars Science Laboratory. 2022-present.
Origins and Habitability Laboratory, JPL. 2020-present.
Science Team Member, Mars Science Laboratory. 2016-2022.
Research Laboratory Technician, Gemological Institute of America, diamond color origin group. 2013-2015.
Research Assistant, Lamont-Doherty Earth Observatory. 2011-2013.

Field Work and Short Courses

2021 Revolutionizing Access to the Martian Surface, Keck Institute for Space Studies, Caltech. (10 day short course, invited.)
2018 Agouron Institute Advanced Geobiology Field School, Caltech. Naukluft Mountains, Namibia, 12 days in the field.
2016 Field component of Sedimentary Cycle of Earth and Mars course, Brown University. Guadalupe Mountains, TX, 5 days in the field.
2013 Research sample collection. Punchbowl Fault, San Gabriel Mountains, CA, 3 days in the field.
2012 Geologic Mapping course, Columbia University. Catskill Mountains, NY, 12 days in the field.
2011 Research sample collection. Champlain Thrust Fault, Adirondack Mountains, VT, 2 days in the field.

Selected first author presentations (last 5 years)

(*denotes oral presentation)

2023 R. Y. Sheppard*, J. M. Weber, L. E. Rodriguez, E. M. Hausrath, L. M. Barge. The effect of clay minerals on Li in a simulated martian groundwater environment. Goldschmidt, Lyon, France.
2023 R. Y. Sheppard*, W. Rapin, V. Tu, L. Lim, T. Gabriel, M. Hughes, A. Fraeman, D. Vaniman. Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration. European Geophysical Union, Vienna, Austria.
2023 R. Y. Sheppard, W. Rapin, V. Tu, L. Lim, T. Gabriel, M. Hughes, A. Fraeman, D. Vaniman. Updated orbital perspective of the Mt. Sharp upper sulfates in preparation for in situ exploration. Lunar and Planetary Science Conference, The Woodlands, TX.
2022 R. Y. Sheppard, A. A. Fraeman, L. M. Barge, J. M. Weber, L. Rodriguez, E. Martinez. Laboratory sediment columns to explore habitability of the martian subsurface under different groundwater conditions. AbSciCon, Atlanta, GA.
2022 R. Y. Sheppard*, A. A. Fraeman, L. M. Barge, J. M. Weber, L. Rodriguez, E. Martinez. Laboratory sediment column simulations of chemical and redox gradients in the martian groundwater environment. Lunar and Planetary Science Conference, The Woodlands, TX.
2021 R. Y. Sheppard*, L. Barge, A. A. Fraeman, J. M. Weber, L. Rodriguez, E. Flores, E. Martinez. Laboratory sediment column simulations of chemical and redox gradients in the martian groundwater environment. American Geophysical Union Fall Meeting, New Orleans, LA.
2021 R. Y. Sheppard, R. E. Milliken, J. M. Russell, M. D. Dyar, E. C. Sklute, S. Bijaksana, M. Melles, & H. Vogel. Mineral and chemical changes in a 100 m long sediment core from Lake Towuti, Indonesia and implications for mafic lacustrine sediments in Gale crater, Mars. American Geophysical Union Fall Meeting, New Orleans, LA.
2021 R. Y.* Sheppard, R. E. Milliken, & K. M. Robertson. Presence of clay minerals can obscure spectral evidence of Mg sulfates: Implications for orbital observations of Mars. Lunar and Planetary Science Conference, The Woodlands, TX.
2020 R. Y. Sheppard, Milliken, R., & Robertson, K. M. Reflectance measurements of clays and sulfates under Mars-like temperature and relative humidity cycles and implications for clay-sulfate assemblages in Gale crater. Lunar and Planetary Science Conference, The Woodlands, TX. (Canceled due to COVID-19)
2020 R. Y. Sheppard, Milliken, R., Russell, J., Dyar, M. D., Sklute, E. C., Bijaksana, S., Melles, M., & Vogel, H. Mineral and chemical changes in a 100 m long sediment core from Lake Towuti, Indonesia and implications for mafic lacustrine sediments in Gale crater, Mars. Lunar and Planetary Science Conference, The Woodlands, TX. (Canceled due to COVID-19)
2020 R. Y. Sheppard* Lamont-Doherty Earth Observatory geochemistry colloquium.
2019 R. Y. Sheppard*, Milliken, R., & Robertson, K. M. Cycling of hydrous minerals and implications for the martian hydrological cycle. American Geophysical Union Fall Meeting, San Francisco, CA.
2019 R. Y. Sheppard, Milliken, R., Itoh, Y., & Parente, M. Mineral stratigraphy around Mt. Sharp suggests aqueous processes affected the entire mound: directions for upcoming rover observations from orbital data. Ninth International Conference on Mars, Pasadena, CA.
2019 R. Y. Sheppard, Milliken, R., Itoh, Y., & Parente, M. Lateral continuity of mineralogical and morphological contacts around Mt. Sharp: linking upcoming rover observations and orbital data. Lunar and Planetary Science Conference, The Woodlands, TX.
2018 R. Y. Sheppard*, Milliken, R., Itoh, Y., & Parente, M. Assessing Lateral Variations in the Mineralogical Stratigraphy of Mt. Sharp: Linking Rover and Orbital Observations. American Geophysical Union Fall Meeting, Washington, D.C.
2018 R. Y. Sheppard*, Milliken, R., Russell, J., Vogel, H., Melles, M., & Bijaksana, S. Signatures of iron cycling in a terrestrial redox-stratified lake and implications for Gale Crater, Mars. Lunar and Planetary Science Conference, The Woodlands, TX.

Invited colloquia and team meeting talks

2022 R. Y. Sheppard. Research Colloquium, Geoscience, UNLV, Las Vegas, NV.
2022 R. Y. Sheppard, Research Colloquium, Astrobiology & Planetary Science, Georgia Tech, Atlanta, GA.
2021 R. Y. Sheppard, Research Colloquium, EAPS, Purdue, West Lafayette, IN.
2020 R. Y. Sheppard, Geoclub Seminar Series, Caltech, Pasadena, CA.
2020 R. Y. Sheppard, Research Colloquium, Jet Propulsion Laboratory, Pasadena, CA. (Canceled due to COVID-19)
2020 R. Y. Sheppard, Geochemistry Colloquium, Lamont-Doherty Earth Observatory, Palisades, NY.
2019 R. Y. Sheppard. Mars Science Laboratory team meeting, NASA Goddard, Greenbelt, MD.
2018 R. Y. Sheppard. Towuti Drilling Project team meeting, Makassar, Indonesia.
2017 R. Y. Sheppard. Towuti Drilling Project team meeting, Bandung, Indonesia.
2016 R. Y. Sheppard. NASA Astrobiology Institute team meeting, Williamstown, MA.

Selected coauthored presentations (last 5 years)

2023 T. C. Marlin, J. M. Weber, R. Y. Sheppard, S. M. Perl, L. M. Barge. Chemical gardens as analogs for prebiotic chemistry on ocean worlds. European Astrobiology Network Association Conference, Madrid, Spain.
2023 W. Rapin, G. Dromart, J. Schieber, B.C. Clark, L. Kah, D. Rubin, S. Gupta, A. Roberts, G. Caravaca, R. Y. Sheppard, E. Dehouck, S. Le Mouelic, A. Bryk, B. Dietrich, P. Gasda, J. Frydenvang, O. Gasnault, N. Lanza. An aridification sequence in the clay-sulfate transition at Gale crater. LPSC, The Woodlands, TX.
2023 C. M. Weitz, K. M. Lewis, E. S. Kite, W. E. Dietrich, L. M. Thompson, C. D. O’Connell-Cooper, J. Schrieber, D. Rubin, P. Gasda, C. Mondro, W. Rapin, S. Gupta, A. Roberts, J. Frydenvang, J. Berger, H. Newsom, A. Bryk, M. P. Lamb, J. Grotzinger, W. W. Fischer, A. Cowart, J. Davis, J. Grant, A. Yingst, W. Farrand, T. Parker, A. Vasavada, A. Fraeman, R. Milliken, R. Sheppard, D. Ming, S. Simpson, E. Rampe, D. Fey, R. Arvidson. The marker band in Gale crater: A synthesis of orbital and ground observations. LPSC, The Woodlands, TX.
2023 A. A. Fraeman, R. E. Arvidson, K. M. Stack, J. Christian, R. Y. Sheppard. Mt. Sharp’s clay-sulfate transition: a regional perspective from orbital spectral and geomorphic datasets. LPSC, The Woodlands, TX.
2023 H. T. Manelski, R. Y. Sheppard, A. A. Fraeman, R. C. Wiens, J. R. Johnson, E. B. Rampe, J. Frydenvang, N. L. Lanza, O. Gasnault. Variability in Mt. Sharp group bedrock as seen by ChemCam passive and active spectra. LPSC, The Woodlands, TX.
2023 R. S. Vachula, R. Y. Sheppard, A. H. Cheung. Preservation biases affect charcoal-based paleofire interpretations. INQUA, Rome, Italy.
2022 R. S. Vachula, R. Y. Sheppard, A. H. Cheung. Preservation biases affect charcoal-based paleofire interpretations. GSA Annual Meeting, Denver, CO.
2022 W. Rapin, R. Y. Sheppard, G. Dromart, J. Schieber, B. C. Clark, L. Kah, D. Rubin, B. L. Ehlmann, S. Gupta, G. Caravaca, N. Mangold, E. Dehouck, S. Le Mouelic, O. Gasnault, J. V. Clark, A. Bryk, B. Dietrich, R. C. Wiens. The Curiosity rover investigates an aridification sequence in the layered sulfate-bearing unit. Europlanet Science Conference, Granada, Spain.
2022 J. M. Weber, E. Martinez, R. Y. Sheppard, L. E. Rodriguez, L. M. Barge. Mars weathering experiments: development and use of continuous-flow packed bed for geologic exploration. Lunar and Planetary Science Conference, The Woodlands, TX.
2022 H. T. Manelski, R. Y. Sheppard, A. A. Fraeman, J. R. Johnson, R. Wiens, N. Lanza, J. Frydenvang. Classification of ChemCam passive spectral targets in Gale crater. Lunar and Planetary Science Conference, The Woodlands, TX.
2022 J. K. Ando, R. Y. Sheppard, A. A. Fraeman, V. Sun. Locations and multispectral features of distinct classes of diagenetic features within the Murray formation, Gale crater, Mars. Lunar and Planetary Science Conference, The Woodlands, TX.
2022 W. Rapin, R. Y. Sheppard, G. Dromart, J. Schieber, B. Clark, L. Kah, D. Rubin, B. L. Ehlmann, S. Gupta, G. Caravaca, N. Mangold, E. Dehouck, S. Le Mouelic, O. Gasnault, J. V. Clark, A. Bryk, B. Dietrich, R. C. Wiens. The Curiosity rover is exploring a key sulfate-bearing orbital facies. Lunar and Planetary Science Conference, The Woodlands, TX.
2022 J. M. Weber, L. E. Rodriguez, R. Y. Sheppard, E. Martinez, L. M. Barge. Understanding habitability and prebiotic chemistry with continuous-flow terrestrial analogs. Invited. AbSciCon, Atlanta, GA.
2022 T. C. Marlin, J. M. Weber, R. Y. Sheppard, S. M. Perl, L. M. Barge. Chemical gardens as analogs for prebiotic chemistry on ocean worlds. AbSciCon, Atlanta, GA.
2022 D. Valadez, E. Flores, E. Martinez, R. Y. Sheppard, R. P. Hodyss, J. M. Weber, J. Castillo, B. Henderson, L. M. Barge. Sorption of prebiotic organics on iron sulfide minerals in ocean world analog systems. AbSciCon, Atlanta, GA.
2022 E. Martinez, E. Flores, D. Valadez, J. M. Weber, T. C. Marlin, R. Y. Sheppard, L. M. Barge. Organic acid adsorption onto iron (oxy)hydroxides under ocean world analog conditions. AbSciCon, Atlanta, GA.
2021 T. F. Bristow, E.B. Rampe, R. Sheppard, R. Milliken. In situ mineralogy of a clay-sulfate transition in Gale crater. American Geophysical Union Fall Meeting, New Orleans, LA.
2021 A. A. Fraeman, M. Hughes, C. Seeger, J. Ando†, S. Jacob, J. Johnson, R. Sheppard, R. Arvidson, M. Rice, J. Bell. Spectral properties of diagenetic features near the clay-sulfate transition in Mt. Sharp. American Geophysical Union Fall Meeting, New Orleans, LA.
2021 S. N. Lamm, L. E. Rodriguez, R. Y. Sheppard, S. M. Perl, A. J. Celestian, L. M. Barge. Classification of iron (oxy)hydroxides and sulfides using mission-ready spectroscopic techniques and machine learning. Geological Society of America Annual Meeting, Portland, OR.
2020 R. E. Milliken, J. P. Grotzinger, R. Sheppard, R. Wiens, R. Gellert, L. M. Thompson, A. Vasavada, T. Bristow, & N. Mangold. The chemistry and mineralogy of an ancient lacustrine sequence on Mars: observations, interpretations, and future prospects. Lunar and Planetary Science Conference, The Woodlands, TX. (Canceled due to COVID-19)
2019 R. E. Milliken, J. P. Grotzinger, R. Wiens, R. Gellert, L. M. Thompson, R. Sheppard, A. Vasavada, T. Bristow, & N. Mangold. The chemistry and mineralogy of an ancient lacustrine sequence on Mars: lessons learned from integrating rover and orbiter datasets. Ninth International Conference on Mars, Pasadena, CA.
2018 D. Morriss, C. B. Sanders, J. P. Grotzinger, J. Busch, L. F. Cury, P. Daoust, W. W. Fischer, B. Howes, D. S. Jones, R. Sheppard, L. L. Nelson, J. P. Pu, D. P. Quinn, J. Wilcots, & R. Swart. Cap Sequence Post-dating Marinoan Glacial Deposits, Naukluft Mountains, Namibia. American Geophysical Union Fall Meeting, Washington, D.C.

Mentoring

2021 Undergraduate advisees hosted by Caltech/JPL: Henry Manelski (now a PhD student at Purdue), Jordan Ando (now a PhD student at U. of Hawaii).
2016-2020 Undergraduate advisees hosted by Brown University: Ana Colon (now a PhD student at U. of Oregon), Christopher Yen (now a PhD student at WashU), Sarah Martinez, Grant Rutherford (now a PhD student at MIT), Catherine Miranda.
2018 Leadership Alliance Program Mentor, Brown University’s Leadership Alliance Program. Led weekly meetings with interns focused on completing a NSF-GRFP-style research proposal, poster presentation, and oral presentation.

Other Service and Outreach

2022 Session Convener, AbSciCon, “Diagenesis and Subsurface Habitable Environments.”
2021 Reviewer, Graduate Women In Science (GWIS) National Fellowship Program.
2020 Panelist, NASA review panel.
2019 Session Convener and Chair, American Geophysical Union Fall Meeting, “Evidence of water- rock interaction throughout the Solar System,” oral and poster session.
2019 Executive secretary, NASA review panel.
2019 Workshop leader, Girl Scout Senior Leadership Conference, Salve Regina University. "Craters, spacecraft, and the surfaces of our Solar System."
2018-present GeoW+ Co-Founder and Graduate Student Leader, Brown University. Intersectional mentoring and social group for the department's underrepresented race and gender undergraduates.
2018-present Graduate Student DIAP Representative, Brown University. Faculty-selected member of the department’s Diversity and Inclusion Action Plan Committee, composed of faculty, graduate students, undergrads, and staff.
2018-present Graduate Student Faculty Representative, Brown University. Student-elected liaison between faculty and graduate students. Attended most weekly faculty meetings.
2018-2019 Graduate Student Climate Task Force Representative, Brown University. Student-elected member of the Department’s Planetary Climate Task Force.