The Strata Ground Penetrating Radar for Rover Based Exploration of the Martian Subsurface

Ground-penetrating radar (GPR) provides a mature and efficient means of identifying the near-surface stratigraphy by mapping the electromagnetic reflectivity of subsurface layering and structure. Typical investigation depths range from less than a meter to tens of meters at spatial resolutions of tens of centimeters to meters, respectively, depending on the system configuration and electrical characteristics of the local geophysical setting. On Mars, a rover-based GPR will define geologically interesting areas for surface in-situ point measurements and can help extrapolate local ground truth to better define the extent and form of a specific deposit, structure, or layer. GPR can also help locate shallow deposits of water or ice, define geological setting based on signatures from analog environments, and help to target and orient rover-based or follow-on drilling operations. Terrestrial GPR systems have been commercially developed to provide optimal performance regarding dynamic range, clutter and sidelobe suppression, and timing stability; while also retaining a high level usability for non-experts in a wide variety of environments. Strata is a similar high-performance GPR that has been tailored for the specific application of Mars exploration from a rover-based platform. It is a 400 MHz impulsive system that can easily be to be mounted on a range of rover platforms. With its high dynamic range of 110 dB, Strata will be capable of probing tens of meters into the subsurface of Mars with a nominal resolution of less than 20 cm. The Strata instrument consists of a low mass and low power digital processor unit and a set of loaded dipole antennas whose specific design and frequency is adaptable to almost any rover configuration. The Strata design is optimized for geologic applications that include definition of geologic setting and detection of water and draws from the maturity of commercial systems developed by Geophysical Survey Systems Inc., which are being adapted and qualified for space flight. Ongoing development of Strata includes system analysis on rover models and mock-ups, prototype antenna testing in Mars analog environments, and laboratory measurements to ensure system reliability under Martian environmental conditions.