The careful study of Martian polar ice caps is one of the key goals of space missions exploring the Red Planet, as they hold crucial information about the evolution of the Martian climate. Although the presence of water on the surface in past geological eras has been demonstrated by a variety of data, the processes that led to the loss of water from the surface and atmosphere are still poorly understood. Accurately measuring the concentration of the three main elements in the polar ice caps - dust, dry ice and water ice - is therefore a key result in determining how much water remains on the Red Planet.

A team of researchers from the Department of Mechanical and Aerospace Engineering and the Space Robotics Investigation Group (SPRING) of Sapienza University of Rome used new methods and mathematical models that combine geophysical data from different space missions to produce the first accurate map of the distribution of water ice at the south pole of Mars. The work, published in the journal Icarus, has important implications for the study of the evolution of the climate of terrestrial planets.

The results obtained made it possible to determine the concentration and distribution of water ice at the Martian south pole: it is estimated that 80% of the surface of these deposits has a water concentration of 50% or more. It was possible to estimate the volume of water in the polar cap, which is between 1 and 1.3 million cubic kilometres.

The mapping of the presence of dust also shows a very high-volume fraction in the western areas, bordering the probable remains of a polar cap formed in earlier geological eras. The polar axis of Mars is believed to have migrated from the position of the older polar cap to the current one, probably due to an impact. The presence of dust could confirm the formation of such deposits in earlier eras.

"Accurate knowledge of the composition of the polar cap is one of the main scientific objectives for understanding the evolution of the Martian climate," says Antonio Genova, study coordinator. "Understanding the natural causes that have led to temporal variations in climatic conditions on similar planets is of great relevance and fits into the context of research into Earth's climate change."

References:

Water ice concentration and distribution in the Martian south polar layered deposits constrained by the lateral variations of their bulk density - Antonio Genova, Flavio Petricca, Simone Andolfo, Anna Maria Gargiulo, Davide Sulcanese, Giuseppe Mitri, Gianluca Chiarolanza – Icarus 2024. https://doi.org/10.1016/j.icarus.2024.116025

Further Information

Antonio Genova
Department of Mechanical and Aerospace Engineering
antonio.genova@uniroma1.it