The surface of Mars is characterized by strong topographic variations. The highest mountain (Olympus Mons) is an old shield volcano with an altitude of more than twice the height of Mount Everest on Earth. The surface features can be roughly subdivided into three types:

• The permanent polar caps, which are covered by ice all over the year. Here, there are clear differences between the northern and southern polar cap. The surface of the northern cap is dominated by water ice, while the southern cap is usually covered by CO₂ ice also during the summer season. The estimated thickness of the water ice sheets on the poles is several kilometers, as can be seen from the height profiles measured e.g. by the Mars Global Surveyor spacecraft (see figures).

• The permafrost regions around the poles extend down to almost ±30° from the equator. During the winter season these regions are partially covered by CO₂ frost and therefore appear bright.

• The rest of the planetary surface consists of thick layers of regolith, which are largely covered by reddish sand of variable thickness. This sand, which is frequently blown into the atmosphere by global storms, is the reason for the characteristic red colour of the planet.

 

In recent years, NASA and ESA conducted a couple of successful space missions to Mars, for example Mars Odyssey, Mars Climate Orbiter, Mars Express, and the polar lander mission Phoenix. These missions provided a lot of new data concerning the distribution of water ice on Mars.

Currently, IWF is proposing a participation in various Mars missions planned for the near future, in particular the NASA mission GEMS. Beyond this, theoretical studies concerning the distribution of permafrost regions on Mars under the influence of climatic variations are an actual topic of research.