TerraForming Mars

One of the astronomers on the "marsobservers" Yahoo group commented that if Mars' permafrost is acidic, the dissolved acid, whatever it is, would reduce the freezing point. I think any other solute would be about as good. Earth seawater freezes at -2C. Mars is thought to have more sulfur in its crust than Earth does, so Mars seawater (permafrost) might have more dissolved sulfate. Also, Mars seawater might have more dissolved carbon dioxide (carbonic acid). So, its freezing point could be even lower than -2C. A eutectic (minimum freezing point possible) solution of calcium chloride is 31% solute by weight and freezes at -50C. So, salt lakes on Mars, near mineral deposits, might be havens for salt-tolerant algae.

If the permafrost froze from water saturated with dissolved CO2 corresponding to a vapor pressure of 1 atm and a temp of 0C, that would lower the freezing point about 0.15degC (from information in several tables in the Handbook of Chemistry & Physics; I had to substitute phosphoric acid for carbonic acid in one table, but I think it's valid). The sulfates alone, in Earth seawater, also lower its freezing point about 0.15degC; so if Mars had twice the dissolved sulfates, it would give another 0.15degC. Though small, these are significant assists.

I've discovered two active Mars-terraforming Yahoo groups, "destinationmars" and "marsinitiative".

Dr. Van Flandern's theory of the origin of the Valles Marineris (VM), is basically correct. I have some things to add:

The Copernican principle (i.e., nothing special about our place and time) is like Occam's razor (i.e., simplest explanation is true). Neither the Copernican principle nor Occam's razor are 100% reliable. That said, the Copernican principle suggests that Phobos-sized moonlets have been decaying into Mars every 40x2=80 million years or so, on the average, for 4 billion years. I made a very rough estimate of the size of moonlet needed to dig the Valles Marineris, and obtained 10 Phobos masses. If there have been 50 moonlets of roughly one Phobos mass each, I would expect that there have been 5 of roughly 10 Phobos masses each, based on the log-log plot of crater size on the Lunar maria (see psi.edu site above). This estimate would be even larger, if the decreasing frequency of asteroid capture were taken into account.

The Valles Marineris lies roughly 15 degrees from Mars' equator, and it isn't perfectly straight. This suggests that it has been deviated by plate tectonic movement since it was formed. It further suggests that the VM was formed mainly by one moonlet. Large impacts at other times, by other moonlets, would have made grooves roughly parallel to, but almost always well separated from, the VM, due to this plate tectonic movement. (If deviations were due mainly to orbital inclination, the canyons should be straight, and often as not, on the other side of the equator from the VM.)

Thus, we see too few VM-like canyons, unless we have the extraordinary luck to be alive a mere 40 million years before the time an almost-unique Phobos crashes. The explanation could be that only moonlets of great tensile strength (e.g., iron asteroids) remain intact to form features like the VM. Carbonaceous chondrite moonlets like Phobos, Deimos, & most inner-belt asteroids, have little tensile strength; they break entirely into rings before hitting Mars.

The largest particles in Saturn's rings are said to be 10m diam; Dr. Van Flandern says that to survive one orbit in Mars' atmosphere, a diameter approaching 1 km is needed. So, the ring particles of Mars would burn up in the atmosphere, or if not, then scatter over the entire equator.

Construction concrete has high compressive but low tensile strength (8-12% of compressive), and zero tensile strength if fractured. The tensile strength of average (uncracked) construction concrete is 3 MPa, i.e., 3 million newtons per sq. m.

Assume a rod 45 km long (the diameter of a hypothetical spherical moonlet 8x the mass of Phobos), density 2 g/ml, oriented radial to Mars. Suppose the tidal acceleration differs by 10 cm/s/s between one end of the rod and the other (as it would, near Mars). A tensile strength of 45 million dynes/cm^2 = 4.5 MPa would be needed. So, even good, unfractured construction concrete would be inadequate. Phobos probably isn't, nor have most of Mars' other moonlets been, nearly as strong as good construction concrete. Most of the moonlets of Phobos' size or larger, formed rings, but a few were strong enough to overcome tidal forces and dig large channels, the biggest of which is VM.

Human physiological considerations for terraforming Mars.

I. Cosmic radiation at Mars' surface is 100x that of Earth. Roughly 1/8 of our *natural* background radiation exposure is from cosmic rays (0.3 out of 2.3 mSv/yr in Australia - in agreement with the total natural background dose 2.4mSv/yr worldwide - according to a source cited in Wikipedia) (the rest is from radio-isotopes inside and outside of us). So, background radiation on Mars would be 13x Earth, because, as far as I know, Mars is not richer in radio-isotopes. This is tolerable:

1. Almost all of the harmful cosmic radiation is, by the time it interacts with our bodies (or behaves as) Xrays & gamma rays like those from nuclear fallout. According to the US Defense Dept. (Effects of Nuclear Weapons, 1962) one foot of packed earth gives 10-fold protection from these rays.

2. Per (1), 3 ft. of Martian regolith would block almost all harmful cosmic rays. This would weigh only as much as 1 ft. of packed earth on Earth, and could be supported by buried Quonset huts, using arching.

3. With dwellings as in (2), someone working outdoors unprotected 2.4 hrs./day, would get only 10x normal cosmic ray exposure and 2x normal total background exposure. Background exposure varies on Earth according to altitude, nearness to the poles, and geology. Furthermore, background radiation levels reportedly were 3x higher (due to higher isotope levels) on Earth for millions of years during the early mammalian era.

4. Mars' low gravity and the need to prevent weightlessness-related bone loss anyway, would encourage the wearing of massy radiation shields.

5. Medical exposure is not included in this discussion because some animal research indicates, and some authors (e.g., Dr. Goff) believe, that a sudden burst of radiation, if *small* (e.g., medical Xray), is, paradoxically, less harmful than the same amount given continuously. A possible mechanism for this, if true, is that free radicals tend to neutralize each other when present in high concentration.

6. It might be that fast rotation, and an atmosphere, are necessary for a planet to have a strong magnetic field. Maybe there's nothing wrong with Mars' core. Magnetization of surface rocks suggests that Mars once was much more magnetized. Maybe ionized wind currents in a thicker upper atmosphere will revive the field, to again shield Mars from cosmic rays.

7. We have generations of experience with increased cosmic ray exposure in professional flight crews, and thousands of years of experience with Andean and Himalayan peoples. The risk of such moderate, chronic increases is well known to be small.


II. Ultraviolet light levels on Mars are very high due to the thin atmosphere and lack of ozone. This also is tolerable if ultraviolet-opaque clothing, including hoods, polycarbonate goggles, and gloves, are worn.

1. Mars' greater distance from the sun gives a helpful extra factor of 2, of reduction in UV.

2. A thicker atmosphere, and especially, more oxygen (ozone), will reduce UV levels.

3. UV exposure can be reduced by remaining in well-shaded areas.


III. What about bone loss or other harmful physiologic effects of chronic weightlessness? Russian astronauts found that intense exercise programs helped a lot, but not enough.

1. Mars has 38% of Earth's gravity, so the effect will be much more moderate than total weightlessness. The body has some capacity to adapt to anything.

2. People will spontaneously make the most of what gravity Mars has, by running, jumping, lifting and standing more, and sitting or lying less. Inertial forces (e.g., from running & jumping) are believed to be indistinguishable from gravitational ones (Einstein's "equivalence principle"). Exercise will be much more effective than it was for the Russian astronauts, because there is a moderate amount of gravity to work against at all times.

3. People might sleep or exercise in centrifuge chambers.

I've been away awhile, found, perused this string when I came back. Thanks Joe Keller, Jim for keeping it going. What I read got me thinking:
Mars, Venus and the Moon are already terra-formed. All rocky planets including the earth are configured by huge, super huge impacts, so I changed my mind about engineering destructive further impacts. I thought:
Wouldn¡¯t it be nice if we could find some way of playing local planetary gravity, some way of transferring gravitational potential energy from Mars to Venus, so that both planets come much closer to Earth, in distance and in climate.
The similarity of sizes, Moon-Mars, Earth-Venus, suggests the possibility of Terraforming the new Venusian sky:
Mars could become a Moon to Venus, distanced from Venus the same distance as the Moon from the Earth, so that from Venus, Mars would be the same size in the sky as the Sun, like the Moon from Earth.
We wouldn't want such a beautifully Earth-like sister system to be too far away, but we wouldn¡¯t want it too close, too tidal. The system¡¯s tidal force would have to be kept much lower than the Moon¡¯s tidal force.
We'd want Venus-Mars to be close enough to easily colonise, go there for vacations and so on, but far enough away to produce low tidal forces on the Earth.
The obvious way of satisfying these requirements would be a binary system 1-2 million miles across. Moon-Earth would be on one side, Mars-Venus on the other; sister systems orbiting one another.
So I am proposing a new Terraforming game, a gravity game. Great if it could be made to work, one way or another, even virtually, as computer games and so on.

"I am sure, as you hear me say this, you do not really believe me, or even believe that
I believe it myself. But nevertheless it is true . . . " Philip K. Dick

When I wrote in that last post that ¡°Mars, Venus and the Moon are already terra-formed¡±, I was alluding to what I was on about in one of my other topics ¡°Planetary Meta-Geologies¡±: the Earth-like impression of views from the Mars Rovers, from the Moon landers, from probes descending onto Titan and Venus.
The Earth's atmosphere and oceans are thus seen as dressing, fluids we might wish to add. I was suggesting that the really important terrestrial forms, continents, basins, mountains, canyons, hills and so on are already there, including oceans filling ocean basins in the case of Titan! This is good news that should not be taken for granted. It's a very big something we don't have to do ourselves.
We are very lucky to find this great work already done for us. It is like being given a huge meal in a super super restaurant . . . thanks to rocky planetary meta-geologies having impacts in common, super huge impacts reconfiguring whole planetary surfaces, as explained in my online ebook's w.1a.pps slide show.
We may get into arranging the dressing ourselves, filling ocean basins with water, adding terrestrial atmosphere and so on (the traditional meaning of terraforming). Ways of doing this, would be to find and deliver the components from beneath planetary surfaces, from outer space and so on, as suggested earlier in this thread and elsewhere.