David A. Senske

Large topographic rises on Venus: Implications for mantle upwelling

Topographic rises on Venus have been identified that are interpreted to be the surface manifestation of mantle upwellings. These features are classified into groups based on their dominant morphology. Atla and Beta Regiones are classified as rift-dominated, Dione, western Eistla, Bell, and Imdr Regiones as volcano-dominated, and Themis, eastern Eistla, and central Eistla Regiones as corona-dominated. At several topographic rises, geologic indicators were identified that may provide evidence of uplifted topography (e.g., volcanic flow features trending upslope). We assessed the minimum contribution of volcanic construction to the topography of each rise, which in general represents less than 5% of the volume of the rise, similar to the volumes of edifices at terrestrial hotspot swells. The total melt volume at each rise is approximated to be 104-106 km3. The variations in morphology, topography, and gravity signatures at topographic rises are not interpreted to indicate variations in stage of evolution of a mantle upwelling. Instead, the morphologic variations between the three classes of topographic rises are interpreted to indicate the varying influences of lithospheric structure, plume characteristics, and regional tectonic environment. Within each class, variations in topography, gravity, and amount of volcanism may be indicative of differing stages of evolution. The similarity between swell and volcanic volumes for terrestrial and Venusian hotspots implies comparable time-integrated plume strengths for individual upwellings on the two planets.

Evaluating Low Concept Maturity Mission Elements and Architectures for a Venus Flagship Mission

NASA’s Planetary Science Division recently commissioned a Science and Technology Definition Team to design a potential Venus Flagship mission. The team developed a list of various mission elements that could serve as parts of an overall mission architecture, including orbiters, balloons at various altitudes, and landed platforms of varying number and lifetime. In order to determine the mission architecture that provided the best science within the desired cost range, teams of scientists developed priorities for the science investigations previously detailed by the Venus Exploration Assessment Group (VEXAG). By categorizing the suitability of mission elements to achieve the science investigations, it was possible to construct a Science Figure of Merit (FOM) that could be used to rate the mission elements in terms of their overall science capability. Working in parallel, a team of technologists and engineers identified the technologies needed for the different mission elements, as well as their technology readiness. A Technology FOM was then created reflecting the criticality of a specific technology as well as its technology readiness level. When the Science and Technology FOMs were combined with a rapid costing approach previous developed, it became possible to rapidly evaluate not only individual mission elements, but also their combinations into various mission architectures, accelerating the convergence on a flagship mission architecture that provided the best science within the flagship mission budget, as well as reducing reliance on unproven technology..