Potential Capabilities of a Rover Deployed Ground Penetrating Radar on Mars

Ground Penetrating Radar (GPR) is capable of addressing a variety of geological problems on the Earth and planets and the instrument has become ensconced as an efficient means for non-intrusive definition of physical properties to 10's of meters depth. Given these capabilities, it is likely that measurements made by a rover-deployed GPR on Mars could constrain near-surface geology and structure. These GPR data could enable 3-D mapping of local stratigraphy and penetrate beneath eolian drift or snow masking layered or ground-ice-rich units and gullies. GPR data could also help define the degree of post-depositional weathering, and provide geologic context necessary to guide other rover instruments. Finally, GPR provides the potential to detect rover hazards (e.g., voids or dust-filled cracks) prior to their engagement. Careful consideration of the various factors influencing radar performance on Mars instills confidence that a GPR can achieve 10-20 m penetration in many settings and motivates development of a rover-deployable impulse GPR. Design of our system has focused on development of prototype antennas in parallel with fabrication of a control unit possessing low mass, volume, peak power, and data requirements of 0.5 kg, 3400 cc, 3 W, and 0.3 MB/day (for 50 meter traverses), respectively. In order to maximize potential penetration and resolution of a Mars GPR, the capability for both high and low frequency investigations has been incorporated. Testing of the prototype antennas in terrestrial analog settings confirms the ability to define near-surface stratigraphy that is critical for accurate interpretation of geologic setting. A model based on the Finite-Difference Time-Domain (FDTD) method is also being used to constrain likely GPR capabilities on Mars and is capable of modeling the complete instrument configuration including antennas, rover, surface roughness, and rocks. Simulations highlight the potential value of investing in such models that may enable identification of diagnostic signatures (such as signal attenuation, frequency content, and phase response) and facilitate inference of dielectric contrasts useful in constraining the local geology and setting.