NASA’s Mars Reconnaissance Orbiter has used its radar to reveal previously unknown structures hidden below the Red Planet’s polar ice.
Like Earth, Mars possesses north and south polar ice caps. Unlike Earth, however, the Martian versions not only contain water ice, there’s there’s a thick layer of carbon dioxide ice acting as a blanket. Frozen CO2, also known as “dry ice”, is known to wax and wane in thickness depending on the Martian season. Though we have a pretty good understanding of the ice caps’ surface features and how they interact with Mars’ predominately carbon dioxide atmosphere, what lies beneath the most ancient layers of ice has been a mystery.
That was, however, until NASA’s Mars Reconnaissance Orbiter (MRO) arrived in orbit in 2006.