An Underground Look at Mars Climate and Evolution

The Mars Reconnaissance Orbiter spacecraft has a long wavelength radar instrument (called SHARAD) that penetrates through hundreds of meters to a kilometer of rock and ice to image layering in the subsurface. SHARAD data have revealed complex layering in the icy Mars polar caps, discovered mid-latitude ice deposits, mapped hundreds-of-kilometer long lava flow interfaces beneath the Martian plains, and have been used to determine the composition of some of the lavas erupted from the large Tharsis volcanoes. This unique view of Martian stratigraphy provides clues as to how the Martian climate has changed through time.