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The Mars Exploration Program Analysis Group (MEPAG) serves as a community-based, interdisciplinary forum for inquiry and analysis to support NASA Mars exploration objectives. MEPAG is responsible for providing the science input needed to plan and prioritize Mars exploration activities. To carry out its role, MEPAG organizes public meetings to gather information and conduct specific studies to address issues and analyze proposed future activities. Based on those activities, MEPAG documents goals, objectives, investigations, and required measurements for the robotic and human exploration of Mars. Updates in response to discoveries and community input are captured in the MEPAG "Goals Document". The four overarching MEPAG goals for the exploration of Mars and its moons are:

Goal 1. Determine if Mars ever supported life
Goal 2. Understand the processes and history of climate on Mars
Goal 3. Understand the origin and evolution of Mars as a geological system
Goal 4. Prepare for human exploration

The MEPAG Steering Committee provides overall leadership, supported by input from the broad Mars community and a MEPAG Goals Committee that maintains the MEPAG Goals Document. Both committees are described in more detail below. If you are interested in serving on either of these committees in the future, please email

MEPAG Steering Committee: The MEPAG Steering Committee (formerly called the Executive Committee) consists of the MEPAG Chair (lead), the previous MEPAG Chair, the Mars Exploration Program (MEP) Lead Scientist, the Mars Program Office Chief Scientist, the Goals Committee Chair, and up to 10 additional members of the MEPAG community. The HEOMD Chief Scientist for Exploration is an ex officio member. Amongst its duties, the Steering Committee organizes virtual and in-person meetings, choosing topics of interest to the community and soliciting reports from Planetary Science Division (PSD) and MEP for discussion. MEPAG may choose to organize Science Analysis Groups (SAGs) to deal with specific issues at the request of NASA or the general community. Results that emerge from SAG reports or findings in response to presentations and discussions at MEPAG meetings are posted to the community on the MEPAG website. Status reports are routinely made to MEP and the Planetary Science Advisory Committee (PAC).

MEPAG Goals Committee: The Goals Committee nominally has two members for each of the four-goal areas, in addition to its Chair. Membership of the Steering and Goals Committees is solicited from the MEPAG community and determined by the Chair and Steering Committee. Logistical and organizational support to the MEPAG, including its analysis groups, is provided by SMD/MEP through the Mars Program Office, located at the Jet Propulsion Laboratory.

To Download the Terms of Reference Click Here


R. Aileen Yingst
SC Chair 2019-present Planetary Science Institute

Dr. Yingst is a planetary geologist focused on the texture and morphology of rock outcrops and clasts. She is Deputy PI on the MAHLI camera on MSL and a Co-I on the SHERLOC/WATSON instrument on the Mars 2020 mission. She is also a Co-I on Dragonfly and PI of the Heimdall camera system launching to the Moon in 2023.


Jeffrey R. Johnson
Previous MEPAG Chair 2016-2019, Johns Hopkins University Applied Physics Laboratory

Dr. Johnson is a planetary geologist who works on visible/near-infrared, thermal and Raman spectroscopy. He is a Co-I on the Mastcam-Z and SuperCam instruments on Mars2020, a Participating Scientist on MSL, and a Co-I on Dragonfly.

Don Banfield

Don Banfield
MEPAG Goals Committee Chair, Cornell University

Dr. Banfield is an atmospheric scientist working on in situ instrument development, including a Martian sonic anemometer/saltation sensor and a polarization nephelometer. He is a Co-I/LTP on the InSight and Perseverance Missions.


Dave Beaty
Member - JPL

Dr. Beaty is the pre-project lead scientist for the MSR returned sample handing (MRSH) studies in the MEP Science Office at JPL. He also organizes topical conferences for input to various Mars activities.

Jacob Bleacher

Jacob Bleacher
Liaison with HEOMD - NASA HQ HEOMD

Dr. Bleacher works on the geologic development of planetary volcanic provinces. He develops technology for in situ, Rover and human exploration. He is the acting Chief Scientist for the Human Exploration & Operations Mission Directorate (HEOMD).

Wendy Calvin

Wendy Calvin
University of Nevada, Reno

Dr. Calvin works on Imaging and Spectroscopy of Martian seasonal polar caps and composition of residual ice sheets. She is a science team member for MARCI/CTX and CRISM instruments on the MRO mssion.

Briony Horgan

Briony Horgan
Purdue University

Briony Horgan is a planetary geologist who uses remote sensing and Earth analogs to study mineralogy and surface processes on Mars and the Moon. She is a Mastcam-Z Co-I and an LTP on the Mars 2020 mission and a Participating Scientist on Mars Science Laboratory.

Dr. Justin Filiberto

Dr. Justin Filiberto
MEPAG Diversity (IDEA) - Co-representative - Lunar and Planetary Institute

Dr. Filliberto is a planetary petrologist and geochemist. His work focuses on planetary volatile budgets with implications for habitability and on magma genesis conditions in planetary interiors.

Scott Hubbard

Scott Hubbard
Stanford University

Dr. Hubbard works on both human and robotic exploration of space. He has served on several National Academy of Science review groups and is a frequent consultant to NASA projects. He is a former Director of the NASA Ames Research Center and was the first Director of the Mars Exploration Program.

Dr. Lynch

Kennda Lynch
MEPAG Diversity (IDEA) - Co-representative - Lunar and Planetary Institute

Dr. Lynch is an astrobiologist and geomicrobiologist that studies life in extreme environments. She is currently focused on subsurface and hypersaline environments as analogs for ancient martian habitable zones as ideal locations to look for preserved biosignatures.

Michael Meyer

Michael Meyer
(MEP Lead Scientist - NASA HQ)

Michael Meyer is the lead scientist for the Mars Exploration Program (MEP) and the Mars Sample Return Program (MSRP) at NASA Headquarters. Formerly he was the lead scientist for NASA’s Astrobiology Program.

Dr. Niles

Paul Niles
NASA Johnson Space Center

Dr. Niles is a planetary geologist and analytical geochemist. He uses laboratory experiments to simulate the ancient aqueous environments in order to better understand the complex micro-scale relationships found in the rock record.

Dr. Johnson

Sarah Stewart Johnson
Georgetown University

Dr. Johnson works on biosignature detection. She is currently investigating multiple Mars-relevant field sites, from silica sinters and acid salt lakes to ancient deposits in the Dry Valleys of Antarctica.

Dr. Zurek

Richard Zurek
MEPO Chief Scientist (emeritus)

Dr. Zurek is an atmospheric scientist. He is the Chief Scientist for the Mars Exploration Program Office at JPL and Project Scientist for the Mars Reconnaissance Orbiter (MRO).

Dr. Mischna

Michael Mischna
MEPO Principal Scientist

Dr. Mischna is an atmospheric scientist. He is the Principal Scientist for the Mars Exploration Program Office at JPL and was formerly Associate Directorate Scientist of JPL’s Planetary Science Directorate. He studies the long-term climate evolution of the martian environment.

  The Goals Committee

Don Banfield Don Banfield (Chair)

Cornell University
Don Banfield is an atmospheric scientist, studying the giant planets and Mars from both remote sensing and in situ perspectives. He has been associated with the Voyager flyby of Neptune, Galileo at Jupiter, and the MER Rovers. He was a Participating Scientist for Mars Polar Lander, and Mars Reconnaissance Orbiter, and is a Co-I on InSight. He is developing planetary instrumentation including a Martian sonic anemometer and a polarization nephelometer.

Sarah Stewart Johnson (Goal 1) Sarah Stewart Johnson (Goal 1)

Georgetown University
Sarah Stewart Johnson is an assistant professor of planetary science at Georgetown University, where her lab focuses on biosignature detection. She is currently investigating multiple Mars-relevant field sites, from silica sinters and acid salt lakes to ancient deposits in the Dry Valleys of Antarctica, all with distinctive features that offer insights into what aqueous environments may have been like on the Red Planet a few billion years ago.

Jen Stern (Goal 1) Jen Stern (Goal 1)

NASA Goddard Space Flight Center
Jen Stern is a planetary geochemist specializing in stable isotopes and the cycling of nitrogen and carbon in planetary environments. She is also actively involved in instrument development for geochemical measurements on planetary surfaces, and has participated in multiple field seasons at Arctic Mars analog sites. Jen is a member of the science team for the Mars Science Laboratory (MSL) Rover Curiosity and the Sample Analysis at Mars (SAM) Instrument Suite.

Alfonso Davila (Goal 1 substitute for Sarah Stewart Johnson) Alfonso Davila (Goal 1 substitute for Sarah Stewart Johnson)

NASA Ames Research Center
Alfonso Davila is an Astrobiologist whose research focuses on the search for evidence of life beyond Earth. He performs theoretical and experimental investigations into the nature, distribution and evolution of life in extreme terrestrial environments considered analogous to planetary bodies of astrobiological interest. He seeks to understand the limits of adaptability and physiological function in these extreme environments, and apply that knowledge toward designing life detection missions to other worlds

Robin Wordsworth (Goal 2) Robin Wordsworth (Goal 2)

Harvard University
Robin Wordsworth is a planetary scientist specializing in the climates and atmospheric evolution of rocky planets. His current areas of interest include the climate of early Mars, evolution of the redox state and nitrogen inventory of the early Earth and Venus, and predictions of the atmospheric composition of rocky exoplanets.

David Brain. (Goal 2) Dave Brain (Goal 2)

University of Colorado
Dave Brain is a planetary scientist interested in the evolution of terrestrial planet atmospheres (including Mars). He specializes in measurements and models of processes that control charged particle and magnetic fields in planetary upper atmospheres, and their contribution to atmospheric escape. Dave is the Deputy PI of the MAVEN mission, and on the science team for the Emirates Mars Mission. Previously he has been involved with both Mars Global Surveyor and Mars Express.

Briony Horgan Briony Horgan (Goal 3)

Department of Earth, Atmospheric, and Planetary Sciences at Purdue University
Briony Horgan is an assistant professor in the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University. Her research program uses mineralogy derived from NASA satellites and rovers, along with lab and field work back on Earth, to understand the surface processes that have shaped Mars and the Moon. Briony is a Participating Scientist on NASA's Mars Science Laboratory rover mission and a Co-I on NASA’s upcoming Mars 2020 rover mission.

Becky Williams Becky Williams (Goal 3)

Planetary Science Institute
Rebecca Williams is a planetary geologist whose research focuses on understanding the history of water on Mars as preserved in the rock record. Building upon knowledge from terrestrial analogs, her research analyzes remote sensing data from orbiters and rovers to reconstruct the processes involved in landscape evolution, and their implications for past climates. She is a Participating Scientist with NASA’s Odyssey (THEMIS cameras) and the Mars Science Laboratory Curiosity rover missions.

Michelle Rucker (Goal 4) Michelle Rucker (Goal 4)

Johnson Space Center
Michelle Rucker has participated in a range of exciting NASA projects, such as: International Space Station (ISS) environmental control and life support system development, operating a two-stage light gas gun hypervelocity impact research laboratory, supervising spacesuit and Extravehicular Activity (EVA) tools projects, ISS exercise equipment system engineering, and Orion crew exploration vehicle test and verification. She currently leads the Mars Integration Group within NASA’s Human Exploration and Operations (HEO) Mission Directorate, developing crewed Mars mission concepts.

Jacob Bleacher (Goal 4) Jacob Bleacher (Goal 4)

Jacob Bleacher’s research interest is the geologic development of planetary volcanic provinces and their subsequent modification and hazard potential through a combination of terrestrial field studies and spacecraft data analysis. He is currently combining his expertise in field and planetary geology to help build and test the science capabilities of NASA’s newest instrument, suit and rover technologies; and is supporting integrated science and technology field tests for human exploration such as NASA’s Desert Research And Technology Studies (Desert RATS), the Hawaiʻi Space Exploration Analog Simulation (HI-SEAS), and field campaigns for NASA’s Solar System Exploration Virtual Institute (SSERVI) team Remote, In Situ and Synchrotron Studies for Science and Exploration (RIS4E).

  Past Executive Committee Chairs

Jeffrey R. Johnson Jeffrey R. Johnson (Served 2016-2018)

Johns Hopkins University, Applied Physics Laboratory
Jeffrey R. Johnson is a planetary geologist who uses remote sensing in visible through radar wavelengths to understand the compositional, mineralogical, and morphological variability of planetary surfaces. He participated in the Mars Pathfinder, Mars Global Surveyor, and Mars Polar Lander missions. He is currently a Participating Scientist on the Mars Exploration Rover and Mars Science Laboratory missions, and is a Co-Investigator on the Mastcam-Z and SuperCam instruments on the Mars 2020 rover.

Lisa M. Pratt Lisa M. Pratt (Served 2013-2015)

was: Indiana University; from 2018: NASA
Lisa M. Pratt is a biogeochemist who studies life on Earth in extreme conditions and uses this information to guide astrobiological investigation of Mars. For example, she was Director of a NASA ASTEP project entitled ”Shallow-Borehole Array for Measuring Greenland Emission of Trace Gases as an Analogue for Methane on Mars (GETGAMM).” In 2018, she became the NASA Planetary Protection Officer.

David Des Marais David Des Marais (Served 2011-2013)

Dave De Marais has studied the geochemistry of the Moon, Earth, and Mars, specializing in isotope geochemistry and biogeochemistry/astrobiology. He is the principal investigator of the Ames Research Center team of the NASA Astrobiology Institute and is a member of the Mars Exploration Rover (MER) and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) science teams.

John Mustard Jack Mustard (Served 2008-2010)

Brown University
John Mustard is a geologist focusing on the composition of planetary surfaces and the processes that modify them. He has studied the Earth and Mars, and his work has shown how dramatic shifts between environmental conditions are shown in the geologic record.

Ray Arvidson Ray Arvidson (Served 2006-2007)

Washington Univ. in St. Louis
Ray Arvidson is a planetary geologist who has worked on the remote sensing of Earth, Mars, and Venus. He is also an expert in rover mobility and has been involved in most of the landed Mars Missions.

Bruce Jakosky Bruce Jakosky (Served 2004-2005)

Univ. of Colorado at Boulder
Bruce Jakosky studies the geology of the Martian surface, the evolution of the Martian atmosphere and climate, the potential for life on Mars and elsewhere, and the philosophical and societal issues in astrobiology.

Jack Farmer Jack Farmer (Served 2002-2003)

Arizona State Univ.
Jack Farmer is a geobiologist focused on understanding the formation of microbial fossil records on the Earth and in detecting such a record on Mars.

Ron Greeley Ron Greeley (Served 2000-2001)

Arizona State Univ. (Deceased 2012)
Ron Greeley had been involved with missions and studies of the Earth, Moon, Mars, and outer solar system moons since 1967. His research focused on understanding planetary surface processes and geologic histories.

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