Publications

Venus formed in the same part of our solar system as Earth, apparently from similar materials. Although both planets are about the same size, their differences are profound. Venus and Earth experienced vastly different evolutionary pathways resulting in unexplained differences in atmospheric composition and dynamics, as well as in geophysical processes of the planetary surfaces and interiors. Understanding when and why the evolutionary pathways of Venus and Earth diverged is key to understanding how terrestrial planets form and how their atmospheres and surfaces evolve. Measurements made in situ, within the near-surface or surface environment, are critical to addressing unanswered questions. We have made substantial progress modernizing and maturing pressure vessel technologies to enable science operations in the high temperature and pressure near-surface/surfaceenvironment of Venus.

Lobate ejecta deposits surround many of the younger impact craters on Mars. Viking Orbiter images indicate the distal parts of the ejecta blankets of these lobate craters are characterized by ramparts. In the absence of detailed topographic data for characterizing the topology of these apparently fluidized ejecta deposits, physical models have relied upon their morphologic characteristics. The most widely accepted model for the formation of such rampart ejecta deposits on Mars invokes fluidization of the ejecta to produce one or more viscous flow lobes. The availability of high-precision topographic data from the Mars Orbiter Laser Altimeter [4,51 facilitates a more quantitative examination of the physical processes involved in the formation of rampart ejecta deposits on Mars. Here we investigate the emplacement constraints that can be developed from the dimensions, topography, and morphology of martian rampart craters. The primary assumptions we have adopted are: (1) the ejecta blanket is emplaced as a continuum flow over the martian surface, rather than an airfall deposit, and (2) that the observable dimensions of the deposits are indicative of flow dimensions during emplacement.

Topography of the Borealis Volcanic Field adjacent to and within Chasma Boreale of the Mars Northern Polar Cap. Results suggest that the volcanic field extent and population is larger than previously thought, with primarily fresh-appearing basaltic shield edifice types.

Landscape and land cover patterns of a selected group of islands in the Azores Archipelago have been assessed on the basis of synthetic aperture radar (SAR) image data of Canada's RADARSAT-1 satellite. These data were acquired as part of RADARSAT-1 baseline data acquisitions called Background Mission. RADARSAT-1 SAR allows for the discrimination of landcover units associated with steep coastal cliffs, dense montane forests, localized areas of intense agriculture, recently active volcanic terrain, and narrow gravel beaches. Human dwellings often appear as distinct targets of bright radar response and can be easily delineated. Despite the presence of a continuous veneer of vegetation, the underlying volcanic terrane and associated landforms, particularly the Holocene caldera structures, are discernable on RADARSAT-1 images. The erosional signatures of gullies and other drainage systems are apparent, as are escarpments with local slopes at or above the angle of repose. Residual cloud forests on several of the islands are mappable, although there is evidence for spatial fragmentation. The all-weather, multi-mode imaging capabilities make RADARSAT-1 a useful tool for studying landcover variations of anthropogenic and natural causes in this perennially cloud-covered region of the world.

We present impact crater geometric properties for more than 5000 fresh martian features using high resolution Mars Orbiter Laser Altimeter digital elevation models and topographic profiles. We discuss global results and significant regional variations. Additional information is contained in the original extended abstract.

This pathfinder business modeling paper presents a first-order economic analysis of a proposed Earth orbital swath mapping laser altimeter (EDGE: Earth Dynamics Geodetic Explorer), a mission concept targeted for launch in the early 2030s under the openly competed NASA’s Earth System Explorers program. EDGE represents a potentially significant leap in global Earth elevation mapping, aiming to achieve approximately 0.10-m vertical accuracy, which is more than a 10-fold improvement over existing global benchmarks of 5–10 m. We evaluate the economic return via a stacked AI-based modeling approach on the estimated $400–$450 million upfront satellite mission investment through a multisector impact assessment extending to ∼2040. Our business-oriented analysis builds upon established figures-of-merit frameworks from comparable Earth observation (EO) programs, particularly the United States Geological Survey (USGS) 3D Elevation Program (3DEP), which demonstrates a 5:1 return ratio from high-precision elevation data at regional scales. Our stacked AI/machine learning-modeling analysis estimates that EDGE’s nearly global coverage of Earth’s solid surfaces (including ice-covered regions, forests, bare land, agricultural areas, and coastal zones) will generate economic benefits of approximately $3–$5 billion annually by ∼2035, escalating to $8–$10 billion annually by 2040 under specific input parameters as commercial applications mature. Assuming launch in 2031, a 2-year mission life, and 1 year for data processing and release, initial economic benefits would begin accruing by ∼2034–2035. This would translate to a projected net present value (NPV) under a moderate adoption case of ∼$33B (at 3% discount) within 5 years of final EDGE mission data release, and a potential benefit–cost return on investment >50:1 (present value) by ∼2040 as the data ecosystem expands in response. Our analysis explores how EDGE’s unprecedented vertical elevation accuracy could realistically catalyze value across multiple sectors, including disaster management, infrastructure development, natural resource management, agriculture, and environmental change adaptation planning. Furthermore, we evaluate how this mission could potentially stimulate a public–private marketplace for orbital topographic data services analogous to the evolution seen in commercial satellite (2D) land imaging, with potential applications extending to lunar and Martian 3D mapping in direct support of NASA’s Moon-to-Mars human exploration program’s highest-priority data and technical gaps circa 2026.

Lobate ejecta deposits surround many of the younger impact craters on Mars. Viking Orbiter images indicate the distal parts of the ejecta blankets of these lobate craters are characterized by ramparts. In the absence of detailed topographic data for characterizing the topology of these apparently fluidized ejecta deposits, physical models have relied upon their morphologic characteristics. The most widely accepted model for the formation of such rampart ejecta deposits on Mars invokes fluidization of the ejecta to produce one or more viscous flow lobes. The availability of high-precision topographic data from the Mars Orbiter Laser Altimeter [4,51 facilitates a more quantitative examination of the physical processes involved in the formation of rampart ejecta deposits on Mars. Here we investigate the emplacement constraints that can be developed from the dimensions, topography, and morphology of martian rampart craters. The primary assumptions we have adopted are: (1) the ejecta blanket is emplaced as a continuum flow over the martian surface, rather than an airfall deposit, and (2) that the observable dimensions of the deposits are indicative of flow dimensions during emplacement.