My work at LPI centers on elucidating the geology and topography of the surfaces of the satellites of the outer planets and Vesta. Of high interest is the unexpectedly rugged topographic relief on Europa and the shapes of impact craters on Europa, Enceladus, and the icy satellites in general. The goal is to understand the geophysical properties of and geologic processes occurring within Europa's floating ice shell and the deformation and mantling of Enceladus surface by plumes, among other things. Topographic mapping of Io is focused on determining volcanic slopes and mountain topography in order to constrain flow rheologies and mountain formation processes on this intensely volcanic world. My work often requires high quality topographic maps, but these must be derived from Voyager, Galileo, and Cassini images using stereo (3-D) image mapping and two-dimensional photoclinometry (shape-from-shading) methods developed here at the Institute. Using these methods, I have been able to map more than 25% of the surfaces of the Galilean satellites of Jupiter and Uranus, as well as nearly all of the surfaces of the icy Saturnian satellites. Mapping of impact crater and basin morphologies on Vesta adds a new dimension to these studies.
I am currently (as of 2012) a Participating Scientist on the Dawn (at Vesta) and Cassini Projects.