Science goals & objectives: understanding surface physical properties, linkages to geologic origins, and current/past habitability are key goals of thermophysical investigations on mars. Lab studies…

This is a $961,627.48 grant awarded by NASA's Shared Services Center to Northern Arizona University (NAU) to conduct research on the linkages between thermophysical properties of Earth and Mars. The research aims to characterize the variability in thermophysical properties of analog terrains to Mars' recurring slope lineae, and assess the measurements necessary to constrain soil moisture content based on remotely sensed thermophysical data. The grant has no set-aside designation, indicating NAU's competitiveness in securing this federal research award. The work supports NASA's Planetary Science and Technology from Analog Research (PSTAR) program goals of furthering planetary research in terrestrial extreme environments and testing technologies for science investigations from mobile platforms.

Science goals & objectives: understanding surface physical properties, linkages to geologic origins, and current/past habitability are key goals of thermophysical investigations on mars. Lab studies that link physical properties to their thermal behavior are often hindered by sample size, the diversity of environments and most importantly, the complexity of natural landscapes. Recurring slope lineae (RSL) may represent the expression of present-day liquid water and are compelling in that they have driven a significant RE-evaluation of how liquid water and habitability on present-day mars. Pore-filling fluids significantly increase the thermal conductivity of the bulk material and this property has been used to constrain the water content of RSL using thermal emission imaging system (THEMIS) data, though the lower bounds were unable to be constrained with existing data. We propose to make measurements that represent data currently available and likely to be available on future missions simulated by our field team and an unmanned aerial vehicle (UAV), with the ultimate goals of: 1) characterizing the variability in thermophysical properties of analog RSL-like terrains, and 2) assessing the measurements necessary (e.g., time of day, pixel scale, topography quality, albedo, etc.) to constrain soil moisture content based on remotely sensed thermophysical data. Methodology: three specific tasks meet science objectives and produce data useful for current and future mars missions. Task 1. Acquire a full suite of observations over a uniform field site and relate this to a thermal model. Light detection and ranging (LIDAR) topography, structure from motion imagery, hyperspectral visible-near infrared (0.4-1.5M), and thermal infrared data of an aeolian sand dune will be acquired over multiple diurnal cycles. These data, when paired with solar and atmospheric flux measurements. Will be used with our comsol-based thermal model to baseline our modeling approach. In situ measurements of the dune will be made with a commercial thermal effusivity measurement instrument, simulating a non-invasive rover-based approach. We will characterize the geologic context and collect samples for grain size analysis to compare to other measurements. Task 2. Acquire a limited suite over multiple field sites. A reduced dataset (similar to what would be available form orbit) will be acquired (visible-near infrared imagery, thermal infrared data) over multiple diurnal cycles and input into our model. Field sites to be visited include alluvial fans, lacustrine sedimentary deposits, and playas with varying soil moisture contents in addition to the sand dune site in task 1 for cross comparison. Each field site will be characterized to assess geologic context and soil moisture with samples collected for grain size analysis. Task 3. Synthesis. We will degrade our data to assess the ability of remote sensing infrared data to discriminate between different terrain. This work place constraints on capabilities of current instruments and guide future instruments on upcoming missions. Simulations to derive thermal inertia and water content will be run and the sensitivity to input parameters assessed (e.g. lower quality DEM, incorrect albedo, pixel size etc.). Relevance to pstar: our proposed work is strongly responsive to and directly addresses the science and technology objectives of pstar. This proposal aims to 1) further planetary research in terrestrial extreme environments that may be analogous to those found on other planets, past or present as we investigate how thermophysical data can help constrain present habitable environments from orbit and landed missions on mars and 2) this proposal will use commercially available off the shelf instruments to test and apply technologies that support science investigations, specifically from mobile science platforms.