Space Telescope Science Institute

Scientists have spotted thinly buried glaciers of water ice on Mars that could one day support a human base on the red planet and help reveal the mysteries of our neighbor's long climate history.

US Geological Survey geologist Colin Dundas noticed a pale band of blue sticking out from the sea of rusty hues in high-resolution photos taken by the Mars Reconnaissance Orbiter (MRO) a few years ago. It turned out he was looking at steep cliffs nearly 330 feet (100 meters) tall with exposed ice. The same thing was later spotted at seven other sites on the surface of Mars.

"This kind of ice is more widespread than previously thought," Dundas told the journal Science. The journal is also publishing in Friday's issue a report he and several other colleagues co-authored on the discovery.

The ice Dundas and colleagues pinpointed doesn't appear to be small veins of frozen water or tiny deposits of frozen molecules squeezed into the pores of Martian soil. Instead, each cliff looks to be the naked face of a glacier, most of which is just barely concealed by a thin layer of soil and rock on the surface.

"These shallow depths make the ice sheets potentially accessible to future exploration, and the (cliffs) present cross-sections of these ices that record past episodes of ice deposition on Mars," reads the report.

In other words, the prospect of a number of glaciers of pure ice just below the surface of Mars is a big deal because they could function as both wells and fueling stations for future human activity. Water ice can be used, of course, for life support as well as for making fuels for surface and space vehicles.

It isn't news that there's ice on Mars. The planet obviously has polar ice caps, wet streaks have been spotted in other cliffsides, and the MRO has previously detected signs of buried ice across the planet. But this appears to be some of the most easily accessible and pure ice found yet.

In addition to helping humans visit Mars, the ice could also tell us tales about the past Martian climate if we were able to drill a core from one of the hidden glaciers and study it.

"That preserved record would be of extreme importance to go back to," Stanford space scientist G. Scott Hubbard told Science.

The likelihood that any of the eight glacial cliffs seen so far will one day support a year-round Martian base aren't great because they're all still at high enough latitudes that the winters would be quite dim and chilly. But Hubbard hopes that NASA may be able to find similar cliffs closer to the equator that could support human exploration.

"What's the cutoff point?" he asks.

That's a question that Elon Musk may also want to ask about this new discovery, given SpaceX's long-term vision of moving a million people to Mars. Enough of these glaciers may just make that vision feasible, so long as all the other challenges (like massive radiation poisoning) are sorted out too.

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