Publications

We present a self-consistent model for the interior of Io, taking the recent Galileo data into account. In this model, Io has a completely molten core, substantially molten mantle, and a very cold lithosphere. Heat from magmatic activity can mobilize volatile compounds such as SO2 in the lithosphere, and the movement of such cryogenic fluids may be important in the formation of surface features in

A careful survey of Galileo SSI global monitoring images revealed more than 80 apparent surface changes that took place on Io during the 5 year period of observation, ranging from giant plume deposits to subtle changes in the color or albedo of Patera surfaces. Explosive volcanic activity was discovered at four previously unrecognized centers: an unnamed patera to the south of Karei that produced

Sets of ridges of uncertain origin are seen in twenty-nine high-resolution Galileo images, which sample seven locales on Io. These ridges are on the order of a few kilometers in length with a spacing of about a kilometer. Within each locale, the ridges have a consistent orientation, but the orientations vary from place to place. We investigate whether these ridges could be a result of tidal flexin

Mars Orbiter Laser Altimeter (MOLA) data have been used to construct Digital Elevation Models (DEM) of the Martian volcanoes in order to determine height, flank slope, caldera depth, and volumes. Summit elevations range from 21.1 km to −0.5 km, and relief varies from 1.0 km to almost 22 km. Average flank slopes are in the range of <1° to ∼10°, consistent with basaltic shield volcanism. The very lo

Each Mars Exploration Rover carries an integrated suite of scientific instruments and tools called the Athena science payload. The primary objective of the Athena science investigation is to explore two sites on the Martian surface where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life. The remote sensing portion of the pay

No abstract available.

We catalog 143 Ionian mountains (montes) and mountain‐like features (mensae, tholi, plana, and small peaks) in order to investigate orogenic tectonism on Io. From this comprehensive list, we select 96 mountains for which there are sufficient coverage and resolution to discern spatial relationships with surrounding geologic features. Three of the 96 mountains are probably volcanoes, 92 appear to be

Focuses on several exploratory missions to the planet Mars to investigate the role of water within the planet. Facts about Mars that were gathered from two National Aeronautics and Space Administration orbiters, the Mars Global Surveyor and Mars Odyssey; Features of Mars that are similar with the planet Earth; Factors that contribute to the possible existence of water in Mars; Background on the ge

Positional control for MDIM 2.1 comes from a new geodetic/photogrammetric solution of the global Mars Mariner 9 and Viking image control network. The details of this network solution are described here. This network incorporates 1,054 Mariner 9 and 5,317 Viking Orbiter images. Accuracy of the new solution is improved primarily as the result of constraining all 37,652 control points to radii from M

The 50,000 year old, 1.8 km diameter Lonar crater is one of only two known terrestrial craters to be emplaced in basaltic target rock (the 65 million year old Deccan Traps). The composition of the Lonar basalts is similar to martian basaltic meteorites, which establishes Lonar as an excellent analogue for similarly sized craters on the surface of Mars. Samples from cores drilled into the Lonar cra

The 5-band Clementine UVVIS data at ∼100 m/pixel were used to examine the compositions of 75 large and small lunar pyroclastic deposits (LPDs), and these were compared to representative lunar maria and highlands deposits. Results show that the albedo, spectral color, and inferred composition of most LPDs are similar to those of low-titanium, mature lunar maria. These LPDs may have consisted largel

In January 2004 the Mars Exploration Rover mission will land two rovers at two different landing sites that show possible evidence for past liquid‐water activity. The spacecraft design is based on the Mars Pathfinder configuration for cruise and entry, descent, and landing. Each of the identical rovers is equipped with a science payload of two remote‐sensing instruments that will view the surround