Radar sounding is a technique used in geophysical exploration and remote sensing to study the subsurface structure of different materials, including ice, soil, rock, and water. The method involves transmitting radar signals into the ground or other materials and analyzing the reflections to create images and maps of the subsurface features. Radar sounding is commonly used in earth science research, glaciology, archaeology, and environmental monitoring to study the composition, thickness, and geometry of subsurface structures. It has also been utilized in planetary exploration, such as in missions to study the subsurface of Mars and the Moon.