An international team of scientists has discovered evidence suggesting water ice may exist around the equator of Mars – a region in which it was believed the vital resource would be unable to survive. The ability to mine and process ice deposits could make future manned exploration of the Red Planet much easier, as it can be used for drinking water and as an element in the manufacturing of rocket fuel.
The team analyzed data collected by the neutron spectrometer on NASA's Mars Odyssey spacecraft between 2002 to 2009. The neutron spectrometer is able to detect and measure the abundance of neutrons in an environment, and through this work out the quantity of an element, in this case, hydrogen.
If an abundance of hydrogen is detected, it could be taken as an indication that there is a buried deposit of hydrogen bearing materials, such as water ice. In 2002, the probe had detected such an abundance of hydrogen beneath the surface at higher latitudes of Mars, and subsequent observations from NASA's Phoenix Mars Lander confirmed the presence of water ice.
For the new study, the team focused their attention on the Martian equator, with an emphasis on a 600 mile (1,000 km) swathe of land nestled between the northern lowlands and southern highlands along the Medusa Fossae Formation.
It had previously been believed that water ice would not be present here due to a lack of thermodynamic stability, however radar-sounding scans of the area suggest the presence of either low-density volcanic deposits, or water-ice beneath the surface.
The team improved the spatial resolution of the old Mars Odyssey data on the region from 320 miles (520 km) to 180 miles (290 km), using image-reconstruction techniques that allowed a view of hydrogen distribution twice as clear as that afforded by the unrefined data.
The higher resolution data revealed a surprising abundance of hydrogen consistent with relatively small buried water ice deposits at the Martian equator, though the team are unsure how they could persist in this environment.
It is possible that the deposits formed a long time ago, when Mars' axis was more tilted than it is today, allowing the atmospheric circulation of an ice and dust mixture from the polar regions that subsequently settled at the present day Martian equator.
However, even if such deposits were protected by a layer of hardened dust, it is unlikely that they would survive to this day, as Mars atmosphere has not been tilted by the degree needed to form equatorial ice deposits for hundreds of thousands to millions of years.
Water ice deposits are not the only explanation for the hydrogen abundance. The signal could also have arisen from the detection of significant quantities of hydrated salts buried beneath the surface. However, the team are unsure how such a deposit could form.
If the signal did turn out to be water ice, it could have serious implications for human efforts to explore Mars. One of the major obstacles with putting people on Mars lies in the cost of reaching the Red Planet. It is extremely expensive to lift heavy payloads out of Earth's atmosphere.
Ice deposits could be processed for, among other things, drinking water and fuel. Whatever explorers can fabricate in situ with the resources that the Red Planet has to offer is one less thing that needs to be transported to orbit. A confirmed deposit of water ice could be a defining factor in the selection of humanity's first outpost on Mars.
The presence of water is also a major factor in understanding the ancient and current Martian climate, as well as determining whether the Red Planet was ever capable of sustaining life.