Terraforming

 

Mars is not truly a "dead" planet... "comatose" might be a better way to describe the distant world. The red planet is a slumbering giant that, with a little help from modern technology, could reawake and become a new home for the inhabitants of Earth. The process is called terraforming, and it means remaking a planet in Earth's image. "It is believed that the warm climate of primitive Mars was created by a strong greenhouse effect caused by a thick CO2 atmosphere. Mars lost its warm climate when most of the available CO2 was locked into the form of carbonate rock due to the action of cycling water. It is believed, however, that sufficient CO2 to form a 300 to 600 mb atmosphere may still exist in volatile form, either adsorbed into the regolith or frozen out at the south pole."* Increasing Mars' atmospheric pressure would surely be a great feat to accomplish. There are several ways that have been proposed to terraform Mars.

Some things to remember about terraforming:

- Contrary to popular belief, Chloral Floral Carbons (CFC's) are not green house gases!

- The best or most effective greenhouse gases are:

-> Carbon Dioxide

-> Ammonia

-> Water vapor

- Methane could have been a significant greenhouse gas in the early Martian atmosphere

-> For Mars, a Methane mixing ratio of 1:2 in a thick CO2 atmosphere could maintain global surface temperatures above 273K even under an early, dimmer Sun.

** Fig. 1.0 (Top Right): Mars polar cap/atmosphere dynamics. current equilibrium is at point A. Raising polar temperatures by 4 K would drive equilibria A and B together, causing runaway heating that would lead to the elimination of the cap. ,

** Fig. 1.1 (Top Left): A Graph showing the calculated Greenhouse effects of Melting the Martian regolith. Here the temperature curve would be moved upwards on the graph sufficiently so that it would lie above the vapor pressure curve everywhere. The result would be a runaway greenhouse effect that would cause the entire pole to evaporate, perhaps in less than a decade. Once the pressure and temperature have moved past the current location point B (Fig 1.0), Mars will be in a runaway greenhouse condition even without artificial heating, so if later the heating activity were discontinued the atmosphere will remain in place.

** Fig 1.2 (Middle Right): .Solar sail mirrors with radii on the order of 100 km and masses of 200,000 tonnes can produce the 5 K temperature rise required to vaporize the CO2 in Mars' south polar cap.The heat production of the these mirrors would be fairly small such that, the importation or production of strong greenhouse gases will be required to force a global temperature rise sufficient to create a tangible atmospheric pressure on Mars. Thought the idea sounds fictional it may be possible to construct such mirrors in space.

** Fig 1.3 (Bottom Left) : Ammonia is a powerful greenhouse gas, and it is possible that nature has stockpiled large amounts of it in frozen form on asteroidal sized objects orbiting in the outer solar system. If moving material from such objects to Mars is envisioned, then such orbits would be quite convenient, because strange as it may seem, it is easier to move an asteroid from the outer solar system to Mars than it is to do so from the Main Belt or any other inner solar system orbit. This odd result follows from the laws of orbital mechanics, which cause an object farther away from the Sun to orbit it slower than one that is closer in. These flight times from the outer solar system to Mars are typically between 25 and 50 years. (Shown in graph)

The Shimizu Institute in Japan believes it is possible to scale back the completion time of such a monumental task by making use of Mars' own resources and by introducing genetically altered life from Earth on the surface. They hope that by doing that they will speed up the process, not just by adapting Mars to support Earth-life, but also by adapting Earth-life to exist on Mars. They wish to make use of the Martian geology to reawaken the planet. They believe detonation of thermonuclear devices deep in Olympus Mons will trigger eruptions of hot magma that would melt and liberate the frozen atmosphere (theoretically).

Dark soil taken from the surface of the Martian moons, Phobos and Deimos, could be transported to the poles where it would be sprinkled all over the poles. This rock would then absorb sunlight and prompt the melting process. Genetically engineered lichen could be introduced on the surface of Mars. The lichen would grow and reproduce, spreading across the surface of Mars, feeding off the water. then aiding the growth of other life forms. This two part approach could be facilitated by:

a.) Controlled de-orbiting of the moons with eventual mining of the moons on the surface.

b.) Mining the moons for the dark rock for transport to the poles.

c.) Crash Asteroids from the asteroid belt, (made of the strong greenhouse gas Ammonia) into Mars.

Another proposal for warming up Mars envisions placing vast mirrors in orbit around the planet to intensify the feeble sunlight. "If the orbital mirror scheme is adopted, mirrors with dimension on the order or 100 km radius are required to vaporize the CO2 in the south polar cap. If manufactured of solar sail like material, such mirrors would have a mass on the order of 200,000 tonnes."* However, melting the ice on Mars may not require such non-trivial feats of engineering.

In order for Terraforming to be effective, the surface of Mars must be heated to a point where anaerobic microorganisms can survive, typically those found in cold deserts on the Earth. Optimistic scenarios, after 200 years of this runaway transformation, have Mars in a new "warm and wet" climatic regime with a ~ 2 bar CO2 atmosphere and a mean surface temperature above freezing. Warm this may be, but unfortunately, not wet. The crust of Mars is frozen to great depths, and rock is such a poor conductor of heat that enormous lengths of time are predicted for any thermal wave from the surface to be conducted through the cryosphere. Mars thaws with excruciating slowness. According to one model, after 200 years a 1 meter global equivalent of water is predicted to have been thawed from the regolith, after 1000 years, 2 m. Just how dry this will leave Mars can be appreciated by comparing these depths with the ~ 2700 m global equivalent depth of the terrestrial hydrosphere. Such water will be mostly trapped in the soil, little will pool at the surface or be available to the cycles so crucial to a vigorous biosphere. To passively thaw the Martian regolith to its complete depths might take a million years.

"It is concluded that a drastic modification of Martian conditions can be achieved using 21rst century technology. The Mars so produced will closely resemble the conditions existing on the primitive Mars. Humans operating on the surface of such a Mars would require breathing gear, but pressure suits would be unnecessary. With outside atmospheric pressures raised, it will be possible to create large dwelling areas by means of very large inflatable structures. Average temperatures could be above the freezing point of water for significant regions during portions of the year, enabling the growth of plant life in the open. The spread of plants could produce enough oxygen to make Mars habitable for animals in several millennia. More rapid oxygenation would require engineering efforts supported by multi-terrawatt power sources. It is speculated that the desire to speed the terraforming of Mars will be a driver for developing such technologies, which in turn will define a leap in human power over nature as dramatic as that which accompanied the creation of post-Renaissance industrial civilization." *

*Quote by Robert Zubrin.

** Graph From Zubrins Book, The Case for Mars.