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Subject: Sorry Henry, There **is** proof on Martian surface chemical composition.
Message-ID: <8610310817.AA15131@s1-b.arpa>
Date: Fri, 31-Oct-86 03:33:30 EST
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Posted: Fri Oct 31 03:33:30 1986
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In Vol. 7, Nr. 29 of Space Digest, Henry Spencer claimed that the

existence of **all** the elements on Mars necessary for life and the

industrial developement of Mars is unproven.  A conclusive proof of this

would be possible only through a detailed survey conducted on the

surface of the planet (an idea I heartily endorse).  However we already

have two excellent data points from the two Viking landers.  While it is

possible that the Vikings landed on some unrepresentative spots, I'm

inclined to doubt it.  Here is a summary of their results:



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        Composition of the Martian Lower Atmosphere

               Carbon Dioxide         95.32 %

               Nitrogen                2.7  %

               Argon                   1.6  %

               Carbon Monoxide         0.13 %

               Water                   0.03 %



              Composition of the Martian Soil

               "Oxygen"               50.1  %

               Silicon                20.0  %

               Iron                   12.7  %

               Magnesium               5.0  %

               Calcium                 4.0  %

               Sulfur                  3.1  %

               Aluminum                3.0  %

               Chlorine                0.7  %

               Titanium                0.51 %

               Potassium               0.25 % (less than)

               nondetected elements    8.4  %



The concentration of "oxygen" is based on the assumption that all of

the other elements are oxides.  The Viking instruments lacked the

capability of detecting elements of atomic weight less than magnesium.

The values observed by the two Vikings closely agreed.  The above

percentages don't add up to 100%, this reflects measurement error.



                    -- For Comparison --

           Average Composition of the Earth's Soil

               Oxygen                 46.6  %

               Silicon                27.2  %

               Aluminum                8.1  %

               Iron                    5.0  %

               Calcium                 3.6  %

               Sodium                  2.8  %

               Potassium               2.6  %

               Magnesium               2.1  %

               -traces-                2.0  %



References:



T. Owen, et. al. "The Composition of the Atmosphere at the Surface

of Mars", J. Geophys. Res., 82, 4635-4639 (1977)



P. Toulmin, et al. "Inorganic Chemical Investigations by X-Ray

Fluorescence Analysis:  The Viking Mars Lander",

Icarus, 20, 153-178 (1973)



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All of the elements necessary to support life exist on Mars.  However

based on this evidence, Mars does lack some elements necessary for

human health and those are:  Iodine and Phosphorus.  Most likely

these elements do exist on Mars but were simply below Viking's

detection threshold.  Even on Earth, Iodine is relatively rare.

The extreme richness in iron is particularly exciting from the

standpoint of industrialization.  Viking performed a simple

experiment of passing Martian soil over a magnet and the iron

filings were clearly visible in the subsequent photos.  Therefore

extraction of iron from the soil should be quite straight forward.

So there you have it.  Mars is a rich planet for industrialization.

All that needs to be worked out is the economics. However, as I've said

before, that's the big problem for all of these space industrialization

dreams.

                  Gary Allen