Planetary Tools
AZ Digital Archive
Astrogeology Data
Earth Explorer
EOS Data Services
Geospatial Data
Maestro for MERh
PDS Image Atlas
PDS Map-A-Planet
PDS Software
Planetary GIS

Mars Rover Software

Current Members


Dr. David A. Williams, Ph.D. - Associate Research Professor

Dr. David A. Williams is an Associate Research Professor in the School of Earth and Space Exploration at Arizona State University, Tempe, Arizona. Dr. Williams is the Director of the Ronald Greeley Center for Planetary Studies, the NASA Regional Planetary Information Facility at ASU. He is also the Director of the NASA Planetary Aeolian Laboratory at the Ames Research Center in California. David is currently performing research in volcanology and planetary geology, with a focus on planetary mapping, geochemical, and remote sensing studies. His research has included computer modeling of seismic wave propagation through planetary interiors, visible and near-infrared spectroscopy of the lunar surface, planetary geologic mapping of the satellites of Jupiter, the planet Mars, and the asteroid Vesta, computer modeling of the physical and geochemical evolution of lava flows in a variety of planetary environments, and petrologic study of lava samples from Mount St Helens. He was involved with NASA's Magellan Mission to Venus and Galileo Mission to Jupiter. He is a Co-Investigator on the European Space Agency's Mars Express orbiter mission, and he was a Participating Scientist on NASA's Dawn Mission to asteroid Vesta. David is a Past Chair of the Planetary Geology Division of the Geological Society of America, and has served on several NASA committees including a five-year term on the NASA Outer Planets Advisory Group.

Dr. Williams' Associate Page


David M. Nelson, M.S., M.A. - Data Manager / GIS Analyst / System Administrator

David is a planetary geologist and ArcGIS specialist, having earned a MS in Geology at ASU in 1997 and a MA in Geography also at ASU in 2012. As Data Manager of the RGCPS, he is developing an ArcGIS lab consisting of several Windows workstations and a GIS database consisting of a wide variety of image datasets acquired from current and past planetary missions for mapping and research.

From 1994 to 2003, he was involved in geology-related research, remote sensing, and planetary mapping, working for the late Dr. Greeley. Included in his research, he has used data from several Mars missions including Viking Orbiter, Mars Global Surveyor, and Mars Pathfinder. He also assisted in early mission planning of the European Mars Express mission, the Mars Exploration Rover missions, and several proposed Mars scout missions. At the beginning of 2007, he joined the Lunar Reconnaissance Orbiter Camera team at Arizona State University under Dr. Mark Robinson where he worked for two years in mission preparation, then as a Mission Planner for the first four years of inflight operations. His current role as Data Manager at the RGCPS began at the end of May, 2013.

Stephanie Holaday - Administrator

Amy Zink, B.S. - Library Information Specialist / Education & Public Outreach Coordinator

Amy earned her Bachelor of Science degree in Geological Sciences from the School of Earth and Space Exploration at Arizona State University in 2009. Amy originally worked at the Ronald Greeley Center's affiliated Planetary Geology Wind Tunnel Facility as a Student Research Assistant from 2006 to 2007. She started working for The Ronald Greeley Center for Planetary Studies as a student worker in 2008 and has since been promoted to full time staff. As a Library Information Specialist and Education & Public Outreach Coordinator, Amy is responsible for maintaining the Ronald Greeley Center library and archives, as well as scheduling and working education tours and public events. Amy also assists researchers at the Center's affiliated Planetary Geology Wind Tunnel Facility.

Christina Leach, B.S. - Program Aide

Christina has always been fascinated by earth science, but her primary interest is meteorology. She earned her Bachelor of Science degree in Geography (Meteorology-Climatology) in May 2012 from Arizona State University. She originally started working for The Ronald Greeley Center for Planetary Studies as a student worker in 2009, but was promoted to full-time staff member in May 2013. She is currently working on the reorganization and preservation of the Center's Mariner 9 collection, but also helps put together the Center's monthly Press Releases. Along with filing, re-shelving, inventorying and cataloging books and other archive material, she aides students, faculty, staff, and the public with the usage of the facility. Whenever possible, she participates in public outreach events to help promote Planetary Geology and the RGCPS.

Meg Hufford - Education/Public Outreach Coordinator

Daniel Ball, M.F.A. - Science Photographer

Graduate Students

"Enzo" Vincenzo Cataldo, Ph.D. Student

Enzo has been accepted to the ASU/SESE Graduate Program in Geology for Fall 2013 and plans to complete a PhD degree. He is now working on a NASA funded project on the mathematical and computer modeling of erosional processes by lava flows on Mars, the Moon and the Earth with Prof. David Williams.

Enzo's background is in Geology, Petrology and Physical Volcanology. He graduated in Geology from the University of Palermo (Italy) and was later awarded a Master's in Planetary Science by the University of Lancaster, his thesis work concerning the numerical and physical modeling of explosive volcanic eruptions on Jupiter's satellite, Io. On that occasion, his main thesis advisor was Prof. Lionel Wilson (Emeritus Professor of Earth and Planetary Sciences, Lancaster University).

Enzo's leisure time comes in the form of sport activities (mostly running), music and hiking/trekking in the mountains and....good food.

Hourly Student Workers

Mary Pendleton Hoffer

Mary has been accepted to the ASU/SESE Graduate Program in Geology for Fall, 2009, and plans to complete an MS degree. Her goals include planetary research and science writing. She is a member of the science team for NASA –funded Automatic Landmark Identification (PI: Dr. Kiri Wagstaff, JPL), working on detection of dust devil tracks. Other research interests include: crater morphology comparisons (Venus, Mars, Callisto and Titan); correlating surface and orbital data; developing standard criteria for image comparison; a dust devil history of Gusev Crater, Mars; lava tube morphology (Moon);  carbonatites and other unusual volcanics, Earth analog studies, and mapping.

Mary’s background is in music. She attended Texas Tech University, the Royal College of Music and Royal Academy of Music, London, and ASU, completing Bachelor, Master and Doctor of Music degrees, as well as Artist Diplomas in piano and harpsichord performance. She worked for 18 years as an orchestral keyboardist with the Phoenix (AZ) Symphony and the Florida Orchestra (Tampa), and she continues to perform with the Myakka River Piano Trio ( Other interests are hiking, gardening, British procedurals, and animals, especially cats.

Kyle Guzman

Ian Blackburn

© 2017 Arizona Board of Regents | Accessibility | Privacy | Contact