TerraForming Mars

(cont., pt. 6)


Frost on Mars. The colder the temperature, the lower the vapor pressure of water ice. This obeys an exponential law which I fitted, to the data for -80 & -90 C from the Handbook of Chemistry & Physics. Also, the colder the temperature, the longer the (Wien’s law) peak radiation wavelength. There might or might not exist a temperature interval for which the total ice minus the vaporized ice gives an insulating sheet of solid frost as thick as half a wavelength of the escaping infrared radiation. Assuming ice density of 0.88, the least amount of atmospheric water for which such a temperature exists (it is -103.1C or -153.6F), is equivalent to an 8.8 micron sheet of ice (7.75 mu of std. density water).
Assuming 11.4 mu ice (i.e., 10 mu water; roughly the average value for Mars, according to a published refereed article) is multiplied by 3.5 by our intervention (i.e., to 35 mu water or 39.8 mu ice), and using the Handbook of Chemistry & Physics vapor pressure table directly (p. 2419, 44th ed.), the warmest temperature that will give such a layer becomes -89.5C (-129.1F). The protection would extend, approximately, down to -103.1 – (103.1 – 89.5) = -116.7C (-178.1F). Over the surface of Mars, the added water amounts to 3.6 cu km; this would be obtained from the 20 megaton “tropical shot” if the material ejected from the craters on Mars is 10% water by volume, and all of it evaporates. For the “temperate shot” we need about 20% water in the Mars surface ejecta. A current estimate is that the ejecta will be 5 – 10% water (Cattermole, “Mars”, p. 199). So, a 240 megaton bomb would be about right to double the range of protection, approximately to a range coinciding with any colder-than-average nighttime temperature on Mars.
It must be that when the vapor pressure of water rises high enough to form much frost on the night side of Mars, the temperature rises enough to speed convection of water to the upper atmosphere where it is broken down and the hydrogen is lost. The dust from the meteor impacts would warm the upper atmosphere and cool the ground, thus reducing convection and conserving water.

(cont., pt. 7)


Soil chemistry. About 3 – 7% of Mars’ surface material is maghemite or magnetite (Cattermole, op. cit., p. 18). The reduction of hematite to magnetite would require 38 kcal per mole of atomic oxygen. Other heats of formation imply that reduction of carbon dioxide; reduction of sulfates or pyrosulfates to sulfides; or reduction of oxides linked to production of sulfides using elemental sulfur; would be about equally economical. Martian soil has a sulfate-rich cement duricrust; the surface also is rich in silicates, oxides, & iron-rich clays, with some carbonates (Cattermole, ibid.). I suggest that the yellow color of Martian dust storms might be due to elemental sulfur.

(cont., pt.


Further ideas. The efficiency of the “temperate shot” could be quadrupled by prior artificial tilting of Phobos’ orbit by exerting torque without work. A superconducting cable around Phobos could magnetize it so that it would be affected by little-known forces, maybe those whose existence has been hinted by Weyl’s unified theory of relativity or by the unexplained systematic residuals of the Michelson-Morley, Morley-Miller & Miller experiments.
The total combined kinetic + (gravitational) potential energy, of bodies in Saturn’s rings, about equals the potential energy due to the sun’s gravity at Saturn’s orbit. An efficient train of bodies moving from Saturn’s rings to Mars, might be possible by catapulting particles off each other initially, then subsequently manipulating their spacing, using a shepherd ship to alter their electric charge.

Joe, Is the mass of mars large enough to hold an atmosphere of any gas? Has anyone looked into this detail? It seems to me the mass is too small to hold gas and without gas pressure liquid water cannot exist so any water would have to be solid as on the moon or Mercury. Water can exist anywhere as a solid when the temperature permits. It is little details such as this that make some things more involved than they seem. If the water got above 273 kelvin it would transform into gas and excape from both Mars and Mercury so the only way for water to be on either planet is below that temperature and not as gas.

Hi Jim!

Thanks for your input. Here at the Iowa State Univ. library where I'm working, there is at least one book (c. 1970) entirely dedicated to the Martian atmosphere. Also, there are many journal articles about the Martian atmosphere; the Science Citation Index (or the computerized version, called "Web of Science") probably lists a hundred of them.

I understood from looking at some of this material, that it isn't easy to know how long Mars will retain gases. The problem is that we don't know exactly what conditions are (temperature, radiation, chemical reactions), let alone what conditions will be, at the appropriate level of the upper atmosphere, from which molecules/radicals/atoms/ions might escape.

It's been written that neutral atomic (or better yet molecular) oxygen or neutral atomic nitrogen would be retained many billions of years (based on the estimated temperature at the appropriate level of the upper atmosphere), but the implication was that if these atoms became ionized (and susceptible to non-thermal accelerations), they might escape faster. Water would become dissociated in the upper atmosphere (i.e., exosphere) and lose hydrogen atoms, which would escape quickly because of their faster thermal motion, leaving behind oxygen. This might be a good way to get oxygen, if you have plenty of water, and Mars does seem to have really plenty of water, presumably as permafrost which melts from time to time.

In summary, a neutral particle of mass greater than or equal to that of a nitrogen atom (i.e., a water molecule, a nitrogen molecule, etc.), will, it has been calculated, usually be held for the life of Mars. But hydrogen will escape when ultraviolet radiation knocks it off a water molecule in the upper atmosphere. Even nitrogen and oxygen might escape if they become electrically charged by ultraviolet radiation.

The idea that liquid water can't exist requires some clarification. Every substance in a condensed phase (solid or liquid), has a "vapor pressure" depending on temperature (e.g., 17.5mmHg for water at 20C; ice has a vapor pressure too, though a small one). Unless it melts or freezes, it can exist in that condensed phase indefinitely when in contact with its own vapor at that pressure, because molecules of the substance are condensing out on the surface as fast as they evaporate or sublimate away from it. At first, exposed water on Mars would evaporate away (or exposed ice on Mars sublimate away), but if there were enough water (or ice), eventually a "partial pressure" of water (other gases wouldn't count) equal to the vapor pressure (i.e., "saturation") would be achieved.

If the water vapor is degraded (i.e., hydrogen atoms knocked off) so fast, that water has to vaporize fast to keep up that vapor pressure, then after awhile all the water would be gone. But if the water vapor is degraded slowly, then permafrost water might replace the losses, and keep the atmosphere saturated, so that the lakes wouldn't have any net evaporative loss.

Boiling happens when the vapor pressure of water is greater than the TOTAL pressure of gases over it. Then bubbles of vapor form in the liquid. But a pure water lake at 0C won't boil, as long as the atmosphere over it has at least 17.5mmHg total gas pressure (water vapor alone suffices if saturated).

- Joe

I think that Phobos & Deimos are asteroids that were captured near the ecliptic plane, on the order of 100 million years ago, by Mars. When meteors hit them, the debris mostly entered nearby orbits which precessed (about Mars' equatorial plane) at a different rate. Eventually much of the crater ejecta would hit the moon again. The relative velocity usually would be large, if this happened near Mars' equatorial plane. So, the equatorial plane became a zone of resistance; this torque moved the moon's orbit into the equatorial plane.
Collisions with ejecta usually would reduce the moon's speed, causing a smaller orbit. Also, collisions would be commoner nearer Mars, so the orbit would be slowed most when near perigee, thus reducing the orbital eccentricity.
On Luna, or on Phobos now, ejecta returns at the speed at which it left. Before Phobos achieved an equatorial orbit, ejecta sometimes returned much faster (due to orbital precession), producing another generation of ejecta. This is why Phobos & Deimos display craters buried in regolith from other craters.