Mars holds many mysteries deep within its dusty world. For decades, scientists have wondered how the Red Planet lost its water and became the dry, desolate land it is today.
As space agencies set their course towards Mars for future exploration, they need to find ways to support astronauts on the planet — not least by providing a stable source of water.
Now, scientists think they have found a reservoir of water ice in Mars' southern hemisphere which could enable these future missions. The discovery not only has implications for human exploration of Mars, but it also helps scientists reconstruct the history of water on the Red Planet.
The discovery is detailed in a study published this week in the journal Icarus.
The find was made using data from NASA's Mars Reconnaissance Orbiter spacecraft, which has been orbiting Mars since the year 2006 and gathering information on the planet's geology and climate, and scoping out potential landing sites for future missions.
The spacecraft's Shallow Radar (SHARAD) instrument detects reflections from Viscous Flow Features, or flow-like structures made up of ice and rock that streak across the middle latitude region of Mars.
After creating a global map of these flow features on Mars, the researchers identified a dense concentration of ice-rich flow features in Nereidum Montes, a geographical feature the northern rim of Argyre basin in Mars' southern hemisphere.
The flow features may be the largest concentration found in an area other than the planet's poles, according to the paper.
"Our radar analysis shows that at least one of these features is about 500 meters thick and nearly 100 percent ice, with a debris covering at most ten meters thick," Daniel Berman, a senior scientist at the Planetary Science Institute and lead author of the new study, said in a statement accompanying the research.
The observations suggest the water ice may have formed relatively recently in Martian history, in the Late Amazonian Epoch. This era began around 3 billion years ago, when Mars experienced lower rates of incoming impacts by asteroids and meteorites, but the water ice may have formed as late as several million years ago.
Scientists have been trying to recreate the history of water on Mars for decades as part of the quest to discover whether the Red Planet may have hosted some form of life during its early history.
Mounting evidence suggests the Red Planet was warm and wet about 4 billion years ago. But over time, Mars' atmosphere was stripped away because the planet lacks a magnetic field like Earth's, resulting in Mars losing its water and making it seemingly inhospitable.
But in more recent years, there have been discoveries of water ice deposits lurking beneath the surface of Mars.
Finding water on Mars is no mere exercise in planetary science. NASA has plans for a human mission to the Red Planet in the 2030s. Water on the Martian surface could serve as a key resource to the upcoming mission — and may even help humans colonize the planet.
The area in which this water ice reservoir was found may be a little tricky for humans to access, however.
"This region would be an interesting landing site due to the large amounts of ice, which could be used as a source for water," Berman said.
"Unfortunately, it is very mountainous terrain and it would likely be very difficult to land there."
Abstract: Mapping of Viscous Flow Features (VFFs), a general grouping of ice-rich flow features that includes Lobate Debris Aprons (LDA), Concentric Crater Fill (CCF), Lineated Valley Flow (LVF), small lobate flows (i.e., glacier-like flows, or GLFs), and arcuate ridges, in the southern hemisphere of Mars shows a dense concentration in Nereidum Montes, along the northern rim of Argyre basin. Further mapping within a subregion in northwest Nereidum Montes (45.3°–48.5° S, 307°–312° E) shows a large number of well-preserved VFFs and ice-rich mantling deposits. Processed SHARAD data across a VFF within the region indicates that it is composed of nearly pure water ice.