Science goals and objectives. The latitude dependent mantle (LDM) is considered to be a widespread (approx. 30-80 degrees latitude), globespanning deposit consisting of ground ICE, dust, and regolith.…

This federal contract award, issued by the National Aeronautics and Space Administration (NASA), provides a grant of $397,083.67 to the University of Texas at Austin. The grant's objectives are to map the distribution and thickness of the Latitude Dependent Mantle (LDM), an ice-rich soil deposit on Mars, using data from the Mars Reconnaissance Orbiter and Mars Global Surveyor. This research aims to improve understanding of the LDM's origin, climate significance, and in-situ resource utilization potential, aligning with high-priority goals of NASA's Mars Exploration Program Analysis Group. The University of Texas System, the parent organization of the University of Texas at Austin, has an extensive track record of receiving federal research grants and contracts across diverse scientific and technical domains. This award does not have a set-aside designation.

Science goals and objectives. The latitude dependent mantle (LDM) is considered to be a widespread (approx. 30-80 degrees latitude), globespanning deposit consisting of ground ICE, dust, and regolith. The LDM is the iconic landform of the recent amazonian (the most recent approx. 2-4 MA) that has been sampled directly by the viking-2 and phoenix landers, and that is the geological substrate for some of the most intriguing processes shaping the surface of modern mars, including gully formation, patterned ground processes, ICE-revealing impacts, and possibly recurring slope lineae formation. Yet key questions about the LDM remain unanswered. What is its spatial extent and thickness? Is IT truly even a mantle (formed by airfall of ICE and dust) or did IT form by sequential enrichment of ground ICE into typical regolith? What is its internal structure and stratigraphy? Accordingly, the goals of this proposal are to 1) map the distribution of 'boulder halo' craters that have penetrated through the LDM and been modified by LDM surface processes to globally determine the thickness and extent of the LDM at a spatial resolution sufficient to detect regional variations in thickness or extent. 2) compare boulder halo crater thickness estimates to other probes of LDM thickness and extent (topography smoothing, frost on/off dates). 3) determine the radar characteristics of the thickest LDM deposits (e.g., detection of subsurface reflections, differences in surface echo associated with shallow ICE). Attainment of these goals will directly permit US to test existing and apparently contradictory hypotheses regarding the origin, age, and ICE content of the LDM. Methodology. To address these goals, we propose 1) a mapping campaign using hirise images to determine the global distribution of boulder halo craters between 30-80 degrees latitude, 2) comparison of boulder halo-derived thickness calculations to surface characteristics measured by mola, NS/GRS, and TES, and 3) measurement of LDM surface and subsurface properties using sharad to map the presence of subsurface reflectors beneath the thickest LDM deposits and to identify potentially diagnostic changes to surface echoes derived from the thinnest deposits. Relevance. The proposed research will use MRO and MGS data to directly improve our understanding of the origin, climatic significance, and isru potential of ICE-rich deposits in the martian mid-to-high latitudes. This work will transform our understanding of the LDM from simply characterizing its surface attributes, to understanding its composition and extent over time. This has been identified as a mepag research priority (goal 2, objective b, investigation 3), and is linked to the mdap high-priority goal of understanding the geomorphology, rock distribution, composition, and causes for textural differences for future mid-to-high latitude landing sites. Thus, the proposed research is a scientific investigation based on analysis of PDS-archived data from two NASA missions explicitly listed in the mdap program description; therefore, the project is directly relevant to mdap.