Scientists say they’ve found significant deposits of water ice hiding extremely close to the surface of Mars, a discovery that could be hugely beneficial for future Mars exploration missions.
The findings, published in the journal Science, were led by Colin Dundas from the US Geological Survey in Arizona. The discovery was made using the HiRISE (High Resolution Imaging Science Experiment) instrument on the Mars Reconnaissance Orbiter.
They found eight mid-latitude locations where escarpments (or scarps), steep banks or cliffs that have been eroded away, had exposed huge cross-sections of ice. In some of the regions, the ice was an astonishing 100 meters (330 feet) thick, and it starts just 1 or 2 meters (3.3 to 6.6 feet) below the surface.
What's more, the ice appears to be layered, not too dissimilar to sedimentary layers on Earth. This means the sheets could show us different geological periods in the history of Mars.
“This gives us a much more detailed window into the vertical structure of some Martian ice sheets, and shows that they have only a thin debris cover and in some cases fine layers,” Dundas told IFLScience.
“The key point is that there are layered ice sheets on Mars that can be quite shallowly buried.”
We already knew that Mars has water ice, but this research highlights just how close some of that ice is to the surface in mid-latitude regions on Mars. This could make it accessible to future exploration missions, such as the European ExoMars rover in early 2021, which will include a drill that can go 2 meters (6.6 feet) under the surface.
The sheets discovered by Dundas and his team are steeply angled, suggesting the ice is strong. A lack of craters also hints that they are extremely young, perhaps less than a million years old.
Huge chunks of rock were seen to have fallen from some sections of the ice, suggesting that erosion is occurring and the ice is retreating by a few millimeters each summer. This is also the result of sublimation, as the ice turns directly into gas in the low-pressure Martian environment.
Future human exploration missions could make use of water ice on Mars, using it as a consumable resource or even as fuel. HiRISE has only imaged 3 percent of the surface so far, so there may well be more such discoveries to come.
“This ice... is expected to preserve a record of climate history, influences the planet’s habitability, and may be a potential resource for future exploration,” the team wrote.