This artist's concept of NASA's Mars Reconnaissance Orbiter highlights the spacecraft's radar capability. The Shallow Subsurface Radar instrument (SHARAD) includes the long antenna that extends horizontally from the spacecraft. The radar is pictured "beaming" down under the surface of Mars. The foreground of the image is a cross section of the planet, showing the surface, the layers below and, ultimately, reservoirs of ice or liquid water.

The instrument will look into the first few hundred feet below the martian surface, as deep as one kilometer.