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Lots of Pure Water Ice At Mars North Pole
brink2012 writes "Planum Boreum, Mars' north polar cap contains water ice 'of a very high degree of purity,' according to an international study. Using radar data from the SHARAD (SHAllow RADar) instrument on board the Mars Reconnaissance Orbiter (MRO), French researchers say the data point to 95 percent purity in the polar ice cap. The north polar cap is a dome of layered, icy materials, similar to the large ice caps in Greenland and Antarctica, consisting of layered deposits, with mostly ice and a small amount of dust. Combined, the north and south polar ice caps are believed to hold the equivalent of two to three million cubic kilometers (0.47-0.72 million cu. miles) of ice, making it roughly 100 times more than the total volume of North America's Great Lakes, which is 22,684 cu. kms (5,439 miles).
The study was done by researchers at France's National Institute of Sciences of the Universe (Insu), using the Italian built SHARAD radar sounder on the US built MRO. SHARAD looks for liquid or frozen water in the first few hundreds of feet (up to 1 kilometer) of Mars' crust by using subsurface sounding. It can detect liquid water and profile ice.
Mars southern polar cap was once thought to be carbon dioxide ice, but ESA's Mars Express confirmed that it is composed of a mixture of water and carbon dioxide.
The study on Mars north polar cap appears in the journal Geophysical Research Letters, published by the American Geophysical Union."
The salty Caspian Sea is the world's largest land-locked body of water. It contains approximately 18,900 cubic miles of water (78,700 cubic kilometers).
Lake Baikal is the world's largest freshwater lake in terms of volume. It contains about 5521 cubic miles of water (23,000 cubic kilometers), or approximately 20% of Earth's fresh surface water. This is a volume of water approximately equivalent to all five of the North American Great Lakes combined.
"Kill 'em all and let Root sort 'em out"
Still cheaper than a liter of printer ink.
Since Mars's Surface Area = 144 million km^2, this implies (for 2.5 million km^3 of ice) that ice caps are enough to supply a water layer 17 meters deep over the entire surface, or maybe 50 meters deep in Hellas and the Northern lowlands, if it was all melted. (If the polar caps entirely melted, that alone would raise the surface pressure above the triple point of water, so liquid water would be possible. The Hellas Basin is deep enough that the pressure is above the triple point now, and it definitely could have liquid water in it if the climate warmed some.)
Note that the polar caps show very clear signs of layering, presumably caused by the long period obliquity oscillations, and are in general very young geologically, so it is not beyond belief that, say, the Hellas basin fills up with water on a regular basis, every 500,000 years or so.
I know from experience that de-ionized water will rust stainless steel. I couldn't remember which minerals, but I found them in the WHO report. The minerals are calcium & magnesium. See page 17, http://www.who.int/water_sanitation_health/dwq/nutdemineralized.pdf So people who drink pure water should takes multi-vitamins to compensate. Or drink a couple of glasses of milk a day.