ESG7@DFVLROP1.BITNET (10/31/86)
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 Allenhenry@utzoo.UUCP (Henry Spencer) (11/03/86)
> 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 development of Mars is unproven... I don't have archives that go that far back, but as I recall, my skepticism was directed at the presence of things like ore bodies, not at the existence of some of the more common elements. > [Viking lander data] The Vikings gave us data on the first few centimeters of surface in two small areas. The close agreement between the two is heartening, but it's still awfully thin evidence to base industrialization on. In particular, we have no idea whether that is the bulk composition or just that of the surface; this matters quite a bit. Topsoil is not really representative of the bulk composition of the Earth's crust. > 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... Based on this evidence, it lacks quite a few in fact. A surprising number of elements are needed for human health, albeit many of them only in trace quantities. The percentage of cobalt, for example, in the human body is minute... but no cobalt equals no vitamin B12 equals death from pernicious [?] anemia. Much more serious than trace elements or even relatively minor ones like phosphorus is the distinct shortage of hydrogen -- water is not a trace requirement! There is probably quite a bit of water in Martian permafrost, but we don't know that for sure. > The extreme richness in iron is particularly exciting... A fair bit of iron, yes, but I wouldn't call it "extreme richness", not when comparing it to things like nickel-iron asteroids. > So there you have it. Mars is a rich planet for industrialization. It may be about as good as any planet, apart from the shortage of water and the annoyingly thin atmosphere. It still has all the problems of planets as industrial bases in general: inescapable gravitational fields, atmosphere that is hard to exclude, a deep gravity well that (particularly in combination with the atmosphere) makes transportation expensive, daily and seasonal temperature cycles, unavailability of solar power during the night. Mars also has a couple of problems of its own: surface roughness and dust storms. Mars makes Earth look flat; its terrain is a major challenge to transportation systems, especially in active areas like the neighborhood of the polar caps -- an area otherwise very interesting because of probable ample supplies of water. And it has dust storms on a planetary scale, very long-lived and widespread. They are bad news for solar power -- those storms are pretty opaque, from the Viking data -- and I believe they also chill the surface pretty thoroughly. I also doubt that spacecraft would find landing or taking off in a dust storm particularly safe. Mars may be a rich planet, but it's got some real problems as an industrial base. "Is the surface of a planet the best place for an expanding industrial civilization?" -- Gerard O'Neill "No." -- ibid -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,decvax,pyramid}!utzoo!henry
cramer@kontron.UUCP (Clayton Cramer) (11/06/86)
> > 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 development of Mars is unproven... > > > 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... > > Based on this evidence, it lacks quite a few in fact. A surprising number > of elements are needed for human health, albeit many of them only in trace > quantities. The percentage of cobalt, for example, in the human body is > minute... but no cobalt equals no vitamin B12 equals death from pernicious > [?] anemia. > > > The extreme richness in iron is particularly exciting... > > A fair bit of iron, yes, but I wouldn't call it "extreme richness", not > when comparing it to things like nickel-iron asteroids. > I hate to be nitpicker, but it most unlikely that cobalt would be lacking if iron was present, since the chemical processes involved are extremely similar. Consider also that Mars shows considerable evidence of cratering, and since nickel-iron meteors are in fact iron-nickel-cobalt meteors, I would be shocked out of my wits if Mars doesn't have significant quantities of cobalt. > Henry Spencer @ U of Toronto Zoology > {allegra,ihnp4,decvax,pyramid}!utzoo!henry Clayton E. Cramer