In a recent study published in the journal Science, researchers from the Arizona detachment of United States Geological Survey reported, with the help of NASA images, that they discovered significant reservoirs of water ice very close to the surface of Mars. Scientists have been convinced that Mars has stores of ice for a while now, but the results of the new study mean that water could potentially be within reach of future exploration missions to the planet.
Previous examinations of the red planet have strongly hinted at the possibility of water and ice on it. Radio scans done by the Mars Reconnaissance Orbiter suggest that there are massive stores of ice that run along the middle of the planet. It’s possible that water may even be found at the planet’s poles. The new study seems to corroborate these findings and it may be the conclusive evidence scientists have been looking for that the planet was once covered in water.
Layers And Layers Of Water Ice
According to the research team, the water ice that is present on Mars is no more than 10 meters (32 feet) below the surface of the planet. In some areas, the water ice could be only one to two meters below the surface. This makes it relatively easy to reach, and the researchers also believe that sheets of water ice litter the landscape of mars, with some of the sheets measuring more than 100 meters (3325 feet) in diameter.
The discovery was made by examining eight steep cliffs on the Martian surface. Erosion had exposed layers of these cliffs containing a silvery-blue substance, what appeared to be ice. The ice was probably created long ago as snow, and the deposits of ice are capped by layers of rock and dust no more than about 1.9 meters (6 feet) thick.
Colin Dundas, a USGS researcher at the Astrogeology Science Center in Flagstaff, Arizona, was the lead author on the study. Dundas explains that deposits of ice could cover as much as a third of the planet’s surface.
“What we’ve seen here are cross-sections through the ice that give us a 3-D view with more detail than ever before,” says Dundas.
The cliff faces, or scarps, were found thanks to the HiRISE (High-Resolution Imaging Science Experiment). The way the cliffs eroded was a stroke of luck for the research team, who are able to peer into the sheets of underground ice, learning about what is underneath the soil of Mars without having to do any digging. The researchers are still puzzled about how these ice deposits initially formed, though once the deposits were finally exposed to the atmosphere, the ice likely sublimates. The ice may go right from solid form into water vapor, meaning that a cliff-face could change form as the ice retreats into it. The strips of ice that were exposed in the cliffsides could be more than 100 meters long. The research team made sure they were actually seeing ice and not just frost covering the ground by using the thermal emission imaging system on the Mars Reconnaissance Orbiter.
The USGS research team identified eight different sites where water could be accessible to any astronauts visiting the planet. Not only would the water ice have value as a resource to those visiting the planet, it also has scientific value. The molecules in the water ice effectively maintain a record of the climate of Mars in the past. By analyzing samples of the ice, scientists could get more information about how the climate of Mars has changed over millions of years. Collecting samples of the ice layers found in the cliff faces would give researchers a detailed history of the planet.
Utilizing Ice Reserves For Manned Space Missions
Human missions to Mars could extract water from the environment by exploiting these ice reserves. Ice could be mined from the deposits or water could be obtained by boiling it out of hydrated minerals. The water could then be used for drinking, or it could be broken down into both hydrogen and oxygen, which could be used as ingredients for rocket fuel and as breathable air respectively.
Yet there is a problem with using the ice deposits that were identified in the study as resources. A recent NASA study was done to find potential landing zones for astronauts, and the cliffs which contain the ice are located around latitudes 55° north or south. Mars explorers are unlikely to use these regions as bases because the Martian winter sees the regions growing dark and cold for long periods of time. As solar power is likely to be one of the primary power sources for explorers, this represents a problem.
Space scientist G. Scott Hubbard, from Stanford University in Palo Alto, California would like to see if similar deposits of ice closer to proposed NASA landing zones could be found. NASA limited the potential landing zones to within 50 degrees of the equator, and Hubbard wants to see where the cutoff point is. Ice deposits found within the Martian tropics would be a substantial boon to NASA explorers.
Even if the deposits of ice are found near NASA landing zones, there’s no guarantee the water would be clean enough for humans to use. High levels of salt within the ice would demand that astronauts bring desalinating units with them to Mars, adding to the cost of exploration. Even more of a problem is that the water could have perchlorates in them, a branch of chemicals common on Mars that are toxic to people. Water gained from the ice would require special filtration if this turned out to be true. It’s impossible to say what the quality of the ice would be like until more research is done.
Efforts to send manned missions to Mars have plenty of problems to deal with, including the fact that atmospheric electrical charges could end up zapping astronauts or equipment. The puzzle of how to utilize stores of ice on Mars is just one more thing NASA will have to grapple with, but the discovery of the ice stores brings many new possibilities with it, in addition to the challenges.