Current research includes Mars sand and dust processes and features, Mars landing site studies, analyses of Galilean satellite geology, and planetary volcanism. Much of the surface of Mars is covered with windblown materials, including extensive dune deposits. Selected areas are being studied to relate the local and regional geology to these materials and to correlate the formational wind directions with winds predicted by a Mars general atmospheric circulation model by collaborator R. Haberle, and a meso-scale circulation model by NASA collaborator S. Rafkin. Information on particle sizes and other physical properties are derived from thermal emission data for comparisons with information derived from high-resolution images. Results from this study shed light onto the complex climate and surface history of Mars.

Experiments are being run to determine the geology and physics of windblown particles on Mars. One series uses the Mars Surface Wind Tunnel at NASA-Ames Research Center in California (operated by ASU). This series involves determining the effectiveness of saltating sand as a means for "triggering" the threshold of fine-grained dust. Another series is being run at ASU using a new apparatus that can simulate dust devils. Experiments are enabling the role of dust devils under Martian conditions to be assessed as a general aeolian process.

As a team member of the Solid State Imaging experiment onboard the Galileo spacecraft, research included study of the large satellites of Jupiter. Current projects include global geological mapping of Europa and analyses of Europa's enigmatic ridges and domes. This work is also related to the NASA Astrobiology Institute studies of Europa, in which Europa is a high priority for future exploration.

Volcanism has been shown to be a process that has occurred on nearly all solid-surface objects in the solar system. Current projects include determining the effectiveness of flowing lava as an agent of erosion of pre-flow terrain. This study includes computer modeling and field studies of lava flows on Earth where erosion has taken place. Applications to planetary surfaces include analyses of lava flows on Mars and Jupiter's satellite, Io. In addition, pseudocraters (features resulting from phreatic eruptions generated by lava flowing over water-saturated terrain) are being studied on Earth and compared to features seen on high-resolution images of Mars.

The current Mars Exploration Program involves a variety of missions, including landers and orbiters. In preparation for these missions and as a member of the Athena Science Team on the Mars Exploration Rover, research is being conducted to determine the best landing sites on Mars to satisfy the science requirements of the program. These studies include detailed analyses of the geology and physical properties of potential sites within the constraints imposed by landing safety and engineering. As a Co-Investigator on the European Space Agency Mars Express mission, work is also being conducted to target sites for high-resolution imaging. Specific targeting includes sites of interest for volcanology, aeolian activity, and exobiology.