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# 6.21 Terraforming Mars

It sounds outrageous, even ridiculous. At a time when we can barely handle the cost of a sample return mission, people dream of greening the red planet. They met at a conference in 2001 on the topic The Physics and Biology of Making Mars Habitable. One of the conference organizers, planetary scientist Chris McKay, recognizes that you have to start small. "I’d like to see NASA send a seed to Mars and try to grow it into a plant," he said. Growing a flowering plant in ambient Martian conditions would be a powerful symbol of humanity's expansion beyond Earth. But the vision is much grander: transformation of the entire planet to allow us to live there. Making another planet Earth-like is called terra forming. The real problem is temperature. Mars has its thermostat stuck at -55 °C so some way has to be found to warm it up. The obvious ploy is to start a runaway greenhouse effect by evaporating the carbon dioxide that's frozen in the polar caps. But Mars can't release its carbon dioxide unless it's warmed up. It's a classic Catch-22.

Images created to show what Mars might look like at various stages while being terra formed. . Click here for original source URL

An MIT undergraduate called Margarita Marinova came up with a way out of this impasse. With astrobiologist Chris McKay, she proposed using artificially created perfluro carbons or PFCs to initiate the warming. PFCs are super-effective greenhouse gases that last a long time. They also have no effect on living organisms or the ozone layer. How long would this take? Marinova did rough calculations. A hundred factories making PFCs, each with the energy of a typical nuclear reactor, would raise the Martian temperature by a degree every fifteen years. With an assist from evaporating carbon dioxide it would take 500 to 600 years to bring the entire planet above the freezing point of water. Warming could also be achieved with a mirror the size of Texas aiming light at the South Pole. This sounds impossibly grandiose but the 200,000 tons of aluminum that are required is only five days worth of Earth production, and mining and manufacturing could be done in space. With the pole raised in temperature by only 5 °C, the CO2 would evaporate and take Mars to the tipping point of global warming. The phenomenon that's so dangerous on Earth works to the advantage of the terra formers.

This artist concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life. Curiosity is being tested in preparation for launch in the fall of 2011. In this picture, the rover examines a rock on Mars with a set of tools at the end of the rover?s arm, which extends about 2 meters (7 feet). Two instruments on the arm can study rocks up close. Also, a drill can collect sample material from inside of rocks and a scoop can pick up samples of soil. The arm can sieve the samples and deliver fine powder to instruments inside the rover for thorough analysis. The mast, or rover?s ?head,? rises to about 2.1 meters (6.9 feet) above ground level, about as tall as a basketball player. This mast supports two remote-sensing instruments: the Mast Camera, or ?eyes,? for stereo color viewing of surrounding terrain and material collected by the arm; and, the Chem Cam instrument, which is a laser that vaporizes material from rocks up to about 9 meters (30 feet) away and determines what elements the rocks are made of. Click here for original source URL.

All this work is just preparation for greening the planet. Mars will have been turned into a cousin of the chilly pre-Cambrian Earth, only suitable for the hardiest of extremophiles. Familiar plant and animals couldn't survive there.Two further huge steps are required. The first is the creation of a self-regulating anaerobic biosphere. There are several candidate organisms for the first Mars colonists. One type of cyanobacterium with the unmanageable name Chroococcidiopsis is found at such extremes of cold, dryness and salinity on Earth that it's often the sole survivor. The cyanobacterium called Matteia can dissolve and bore through rock, fixing nitrogen and liberating carbon dioxide. Then there’s Deinococcus radiodurans. This microbe can survive a hundred times the radiation does that would kill a human in minutes; it keeps multiple stacked copies of its DNA so it can repair damage quickly. Naturally occurring microbes could be augmented with genetically engineered varieties. The goal would be to establish the biosphere and release enough oxygen, nitrogen, and carbon dioxide to raise the atmospheric pressure from its current 0.7% of Earth to about 2% or 3% of Earth's sea level pressure.

The second step is to introduce plants and boost the atmosphere to a breathable level. Generating trillions of cubic meters of air isn't trivial! Many changes will occur simultaneously. Water will carve out rivers and cause erosion. Soil will begin to form, transforming the surface which is currently a meteorite-pulverized form of rock called regolith. When Mars has a new and complex set of biological chemical cycles in play, different from those on Earth, it's very difficult to predict the actual conditions. Chris McKay thinks the first step might be done in little more than a century but the second could take thousands or even tens of thousands of years.

Terraformers often neglect the cost and difficulty of shipping all these "starter" microbes and plants from the Earth. An intriguing alternative is to build a self-replicating oxygen factory. The single 100-ton seed unit would make oxygen by heating the rock, which contains oxides of silicon, iron, calcium, titanium and aluminum. Then it would use the metals mined from that same soil to construct replicas of itself. A NASA study showed that a factory with power consumption of 1 megawatt and replication time of a year could generate a breathable atmosphere in a couple of hundred years. And as a byproduct the network of factories would generate 1000 trillion tons of refined metals and a billion megawatt distributed power source that's self-repairing and available for other industrial use.