Microwave remote sensing of physically buried objects in the Negev desert: Implications for subsurface Martian exploration

We report the remote detection of a physically buried specular reflecting object using microwave radar at Ashalim in the northern region of the Negev desert, Israel. Such detection provides an important terrestrial analogy for the potential detection of specularly reflecting subsurfaces under the desiccated regolith on Mars, such as ground‐ice and liquid water. At Ashalim, a scatterometer operating in the P‐band (441 MHz, 68 cm) was mounted on a cherry picker truck at a height of 8 m and used to detect two triangular aluminum mesh reflectors (forming a one meter square area reflector) buried down to a depth of 8 cm in dry sand. The decrease in measured backscattered power with increasing burial depth of the reflector is clearly evident. The experimental results compare well with a theoretical model that incorporates radar absorption effects arising in the sandy subsurface layer and radar interference effects arising from phase differences between reflections from the surface and buried reflector. This experiment and the associated modeling approach is the first of a series of planned experiments, which we outline for the detection and the theoretical evaluation of buried reflectors using remote microwave and VHF radar. We identify many potential subject areas for subsurface remote sensing in the Martian domain, particularly groundwater/ground‐ice.