Automated feature detection and hydrocode modeling of impact-related structures on Mars

A substantial amount of evidence has accumulated over the past two decades for the presence and persistence of liquid water on the surface of Mars early in its history—from the oldest observable surfaces up to approximately 3.5 billion years ago. The presence of liquid water on modern Mars is possible only under peculiar circumstances, and for ancient Mars these circumstances are further limited by predictions of the Standard Solar Model that the Sun was significantly fainter at that time. Large asteroid and comet impacts have been suggested by Carr (1996) [95] and Segura et al. (2002) [403] as a possible triggers of warm and wet climate episodes early in Martian history. My goal is to model impacts into stratigraphically complicated media, specifically targets containing water ice in various morphologies, in order to determine a lower bound on the energy and size scales of impact events that could trigger such a climate shift, and thus establish an upper bound on the frequency of such events. To do this, I used various analytical and numerical modeling techniques, including the RAGE hydrocode RAGE [292] is an Eulerian hydrocode that runs in up to three dimensions and incorporates a variety of equations of state including the SESAME tables maintained by LANL. In order to test the accuracy of RAGE predictions before applying it to the problem. I compare code results against analytical models (verification) and laboratory experiments (validation) that are related to the problem. Specifically, I compare RAGE against experiments ([392], [358]), and analytical crater scaling models ([226], [221], [218], and [322]). From there, I examine the potential effects of impacts on water ice in the Martian subsurface, first by examining the evolution of the temperature and pressure profiles of an impact into a geologically simple, ice-free target, and then exploring the effects of ice content and morphology

Planetary Defense Mitigation Gateway: A One-Stop Gateway for Pertinent PD-Related Contents

Planetary Defense (PD) has become a critical effort of protecting our home planet by discovering potentially hazardous objects (PHOs), simulating the potential impact, and mitigating the threats. Due to the lack of structured architecture and framework, pertinent information about detecting and mitigating near earth object (NEO) threats are still dispersed throughout numerous organizations. Scattered and unorganized information can have a significant impact at the time of crisis, resulting in inefficient processes, and decisions made on incomplete data. This PD Mitigation Gateway (pd.cloud.gmu.edu) is developed and embedded within a framework to integrate the dispersed, diverse information residing at different organizations across the world. The gateway offers a home to pertinent PD-related contents and knowledge produced by the NEO mitigation team and the community through (1) a state-of-the-art smart-search discovery engine based on PD knowledge base; (2) a document archiving and understanding mechanism for managing and utilizing the results produced by the PD science community; (3) an evolving PD knowledge base accumulated from existing literature, using natural language processing and machine learning; and (4) a 4D visualization tool that allows the viewers to analyze near-Earth approaches in a three-dimensional environment using dynamic, adjustable PHO parameters to mimic point-of-impact asteroid deflections via space vehicles and particle system simulations. Along with the benefit of accessing dispersed data from a single port, this framework is built to advance discovery, collaboration, innovation, and education across the PD field-of-study, and ultimately decision support