Synergistic Terraforming
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| Date |
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5.2.2002 |
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| Submitted by |
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Eric M. Choi |
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| Title |
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Synergistic Terraforming |
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| Source |
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Robinson, Kim Stanley. Mars Trilogy (Red Mars, Green Mars, Blue Mars) Fogg, Martyn J. ‘A Synergistic Approach to Terraforming Mars’, In: Journal of the British Interplanetary Society, 45 (1992)McKay, Christopher P., Owen B. Toon and James F. Kastings. ‘Making Mars Habitable’, In: Nature, 352 (August 1991) |
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| Context |
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In 2026, the United Nations sponsor a mission to terraform Mars. The settlers soon find themselves divided into rival factions: the Greens who wish to pursue full terraforming at any cost, and the Reds that want to keep Mars in its pristine condition. This division, combined with the political and economic tensions with Earth and the ethnic rivalries among the settlers, eventually erupts in revolution. Management of the terraforming project is shifted from the UN to a conglomerate of multinational corporations. With greater monetary and technological resources at their disposal, the changes to the Martian climate accelerate. But some of their techniques appear to do more harm than good to the nascent environment, and a second revolution sweeps the planet. A compromise between the Reds and the Greens is reached in which the full terraforming pursued by the corporations is abandoned in favour of a minimal Arctic-like environment in which humans can survive but much of the planet is kept close to its original state. When an environmental catastrophe strikes Earth, humanity turns to Mars as both a refuge and a source of solutions. Eventually, the scientific and social changes brought on by the terraforming of Mars and the environmental restoration of Earth spawns a new Renaissance, giving humanity the technology to not only settle the rest of the Solar System but also to voyage to other systems. |
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| Description |
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The first habitats were simple barrel-vaulted chambers. When completed, they were covered by 10 m of sandbagged regolith to stop radiation and allow the interiors to be pressurized to 450 mbar. The building materials for these habitats were derived from indigenous resources. Bricks were made of clay and sulphur from the regolith mixed with nylon from the spent lander parachutes to increase tensile strength. This mixture was poured into brick moulds and baked under compression until the sulphur polymerised. Once the initial settlements were established, the process of terraforming was started. The first step was to increase the surface temperature of the planet. A giant mirror was stationed in areostationary orbit to reflect sunlight onto the dawn-dusk terminator. This mirror was constructed from the solar sails of the cargo freighters from Earth. When a new freighter arrived at Mars, its sail would be detached and linked to a large collection of earlier sails parked in areostationary orbit. The mirror was programmed to swivel to reflect sunlight on the terminator, adding a little bit of energy to each day's dawn and dusk. Factories were built across the planet to produce halocarbon-based greenhouse gases from local sources of carbon and sulphur. These had to be constantly released into the atmosphere to offset the destruction caused by ultraviolet radiation. In addition, 1,000 windmill heaters were distributed around the equatorial regions. These windmills were small, 5 kg magnesium boxes with four vertical vanes on a rod that projected from the top. The heating element was an exposed metal coil at the base of the windmill that radiated like a stove top. In a good wind, the element was supposed to heat up to about 200'C. Further heating was provided by 200 nuclear reactors (nicknamed "Chernobyls") that were stationed across the planet, and by reducing the albedo of Mars through the deployment of dark organic matter. The next step was to genetically modify terrestrial micro organisms to survive on the Martian surface. These organisms had to be resistant to cold, dehydration, and ultraviolet radiation, as well as have a low requirement for oxygen and be able to live in rock or soil. Unfortunately, no single terrestrial microbe had all these traits, and those that had them individually were slow growers. The engineers therefore started a "mix-and-match" program in which genes were recombined from a variety of terrestrial algae, methanogens, cyanobacteria, and lichens. Promising candidates were tested in an old habitation module that had been modified into a "Mars jar". Cultures were introduced into this sealed facility and were studied through teleoperation by scientists in an adjacent module. As a safety precaution, all the genetically modified organisms had "suicide genes" to prevented them from overwhelming the biosphere. Out of these efforts were produced a variety of fast-growing lichen, radiation-resistant algae, extreme-cold fungi, and a helophytic bacteria that ate salt and excreted oxygen. Animalcules went through the regolith, turning nitrates into nitrogen and oxides into oxygen. A symbiont of cyanobacteria and a Florida platform bacteria called thiobacillus denitrificans was able to go deep into the regolith and converted the rock sulphates into sulphides. This fed a variant of Microcoleus, which grew large dendritic filaments into the ground. These roots went straight through the regolith down to the bedrock, melting permafrost as it went. Like the colony in Mining the Oort, the settlers in Robinson's novels built a Skyhook space elevator to provide routine and economical transportation between the surface of Mars and space. This Skyhook was constructed out of an Amor-class carbonaceous chondrite asteroid. Self-replicating factories extracted resources from the asteroid to construct the cable, which was made of carbon nanotube filaments. These nanotubes consisted of carbon atoms linked in chains. The filaments were only a few metres long, but were bundled in clusters with their ends overlapping. The bundles were then consolidated with other bundles to make a cable 9 m in diameter. Once the cable was completed, it and what was left of the asteroid was moved into an areostationary orbit around Mars with a mass driver propulsion System. Using data from an array of sensors, a powerful computer used a set of attitude control thrusters to control the complex dynamics as the free tip of the cable swung down towards the! surface of Mars. It was finally anchored to the town of Sheffield, atop Pavonis Mons. After anchoring, the cable was set with a controlled oscillation that allowed it to dodge the orbit of Deimos. The solar sail-based mirror was for a time supplanted by a more advanced System. This new mirror consisted of two parts, an "annulus" and a "stoletta7'. The annulus spun around Mars in a polar orbit. Its mirror ring faced the Sun and reflected inward the peripheral light that would otherwise just miss the planet. The light was focussed on the Sun-Mars Ll point, where the stoletta was stationed. The stoletta consisted of a web of slatted rings that were set at angles like circular Venetian blinds. Sunlight striking the stoletta cascaded through these blinds, hitting the Sun-side of one and then the Mars-side of the next, all the way down to the planet. This was done to harness countervailing solar radiation pressure for station keeping purposes. Since the soletta was placed at L1 directly between the Sun and Mars, the stoletta effectively "replaced" the Sun in the sky of Mars. This increased the solar intensity by 20%. A third mirror, much smaller than the soletta, was placed in low-Mars orbit. It caught some of the light from the soletta and focussed it onto remote regions of the surface. This small mirror could heat a square kilometre area up to 5,000 K. The plan was to melt the regolith and release hundreds of millibars of volatiles, primarily carbon dioxide, into the atmosphere. The annular mirror and soletta were eventually abandoned because the System was too successful in warming the planet, resulting in an excessive release of carbon dioxide. To scrub this unwanted gas, trees were planted. Once the temperature and pressure of the planet reached near Arctic conditions, it was found that terrestrial trees could be planted on Mars with little genetic modification. It turned out that a lot of spruce and pine species had temperature tolerances much lower than was needed in their native terrestrial habitats due to holdover adaptations from the last Ice Age. Other trees that were planted included the white spruce Picea glauca and lodge pole pines, both of which were modified with salt tolerance genes extracted from tamarisks. With the increasing oxygen content of the atmosphere came the introduction of animal life. The first of these were genetically altered insects like black midges, bees, and ants. Later, small mammals like moles were added for soil aeration, and birds were introduced to help spread seeds. Once a food chain was established, predatory animals like the Ursus maritimus polar bear, the lynx, and the bobcat were brought in. Most of the animals were modified with high altitude adaptation genes to allow them to survive in the reduced Martian atmosphere. The warming of the planet had caused the permafrost and polar ice to melt and reform on the surface as vast glaciers. Until this ice was melted, too much solar energy would be reflected back into space, preventing the formation of a full hydrological cycle. But once the ice was melted and liquid oceans were on the surface of Mars, a water cycle would be achieved and the terraforming process would essentially be complete. The proposed methods of melting the ice included feeding the exhaust from nuclear power plants into the glaciers, scattering black algae onto the ice, using microwave and ultrasound transmitters as heaters, sailing icebreakers through the pack to break it up, and detonating thermonuclear explosions deep underground. The final state achieved was one of "least-impact" terraforming or "ecopoesis". A breathable but water-poor and largely carbon dioxide atmosphere was created, but only up to a 6 km contour. Thus, the Martian surface became to resemble the Arctic, while its oceans emulated the Antarctic. At high altitudes the air was kept too thin for humans. Since the vertical relief on Mars was so extreme, most of the indigenous geological features remained above the bulk of the atmosphere and thus retained their natural state. The problem of the carbon dioxide rich atmosphere was solved not by changing Mars but (like Man Plus) by altering the physiology of the human settlers. A medical procedure was developed in which the genes that coded for certain characteristics of crocodile haemoglobin could be introduced into mammals. Crocodiles could stay underwater for long periods of time because the carbon dioxide that usually built up in the blood instead dissolved into bicarbonate ions that bound! to the amino acids in the haemoglobin. This bond caused the haemoglobin to release oxygen molecules, which means that in one stroke this crocodile gene could increase both carbon dioxide tolerance and oxygen efficiency. |
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| Comments |
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The terraforming technologies described in this trilogy were based largely on work already published in the scientific literature, most notably that of Christopher McKay and Martyn Fogg. Robinson appears to have been particularly influenced by the latter's concept of “synergistic terraforming". This is the idea that no single technique for terraforming Mars can work in isolation, and that only a combination of several technologies, requiring a massive industrial effort on both the planet's surface and in space, can hope to succeed.But there are differences between the terraforming technique portrayed in the trilogy and that most often described in the scientific literature. McKay wrote of a two-phase approach to terraforming, in which the planet is first warmed by a massive release of carbon dioxide, followed by a modification of the atmosphere to scrub out the carbon dioxide and increase the oxygen content in order to support complex life. The time scale for such a two-phase approach was estimated to be about 100 years for the first step and up to 100,000 years for the second. McKay explicitly stated in his paper that he had limited consideration in his study to technologies that were not far beyond the current state-of-the-art. In contrast, Robinson postulates that through new technologies and a massive synergistic industrial effort, a single-phase approach to terraforming may be possible in which the final habitable atmosphere is directly reached. While the actual terraforming of Mars, be it single- or two-phase, may not be feasible in the near-term, the manner it was portrayed in these novels do suggest some contemporary “precursor" work that may be practical. The importance of micro organisms in the terraforming of Mars was emphasised not only in this trilogy but also in Mars Plus and Mining the Oort. One area of research that could be conducted immediately would be to study the viability of terrestrial microbes exposed to a simulated Martian environment like the Mars-normal tank described in Section 3.3 or the "Mars jar" of Red Mars. In addition to identifying promising candidates for future terraforming, such a study would have one major near-term benefit. Under international planetary protection agreements, landers like the NASA Mars Pathfinder and the ESA Beagle 2 must be sterilised to prevent the forward contamination of Mars by terrestrial organisms. Such sterilisation is a difficult and expensive procedure. It would be useful to have some quantitative data on the survival probability of terrestrial microbes in a Martian environment in order to optimise these sterilisation procedures. Both the Mars trilogy and Mining the Oort mentioned the utility of the Skyhook space elevator as an effective and economical method of transportation between space and a planetary surface. For such a system to become a reality, two engineering problems need to be overcome. First, there is currently no terrestrial material that has the tensile strength required of such a structure. The key words here are "currently" and "terrestrial". As research in material science progresses in terrestrial laboratories and aboard the International Space Station (ISS), it is possible that a material with the necessary strength, perhaps something like the carbon nanotube filaments described in these novels, will be formulated to make a Skyhook feasible. The other engineering problem that will require research is the dynamics of large flexible space structures in general, and tethers in particular. In the Mars trilogy, the Skyhook cable is described as undergoing a controlled oscillation to avoid the orbit of Deimos. Remarkably, even after four decades of space flight such flexible motions are not well modelled and the available archival flight data is limited. There are several reasons for this. To save weight, appendages such as solar panels and antennae are designed to hold themselves up only the micro gravity of space. On the ground, these components must be supported by external mechanisms. Since this changes the structural characteristics of the spacecraft, ground-based tests seldom provide an accurate measure of how they will actually behave in space. Computer and mathematical models are not much help for precisely the same reason -- there are no ground tests available that can verify with a high degree of confidence whether these models are correct. The reason the database of in-flight experience from actual missions is still fairly limited because many satellites were artificially stiffened to make them more "predictable", and some computer codes still simulate spacecraft as rigid bodies.[24] This is obviously unrealistic, for a contemporary spacecraft with lots of booms and solar panels - or a future Skyhook running from an asteroid in areostationary orbit to the surface of Mars - is anything but perfectly stiff. To date, the most ambitious testing of a space tether was that of the Agenzia Spaziale Italiana's (ASI) Tethered Satellite System (TSS), which flew on Space Shuttle Atlantis Mission STS-46 in 1992, and Columbia STS-75 in 1996. Unfortunately, problems marred both tests. Ort STS-46, the TSS reached a maximum distance of only 256 m instead of the planned 20 km due to a jam in the tether. During the re-flight on STS-75, the tether snapped just short of full deployment due to electrical arcing caused by a material defect in the line, and the TSS payload was lost. However, it should be noted that neither of these mishaps was due to any fundamental problem with the tether concept or a design flaw in the TSS. Given the relative scarcity of empirical data on the behaviour of flexible structures in space, and the potential importance of tethers in future space exploration and settlement, it is recommended that flight spare or engineering model of the TSS should be refurbished and re-flown on a future Space Shuttle mission. Finally, the testing of orbital mirrors should also be continued. The Russians have flown two prototypes. A 20 m diameter mirror called Znamya-2 was deployed from the Progress M-15 cargo vessel in 1993, and a larger 25 m mirror called Znamya-2.5 was tested in 1999. Unfortunately, the latter experiment failed because the mirror accidentally got snagged on a docking antenna while it was being deployed from the Progress M-40 supply ship. There were plans for a 70 m Znamya-3, but it would have required a substantial modification to the attitude control system of the Progress spacecraft to control a structure with such a large moment of inertia. As an alternative, perhaps it may be desirable to fly Znamya-3, or a comparable European experiment, aboard an ESA Automated Transfer Vehicle (ATV) as a secondary payload. The mirror could be deployed and tested after the ATV has delivered its cargo to the International Space Station, just before the planned destructive re-entry into the atmosphere. Perhaps the conclusion reached by Fogg in his paper could apply equally well not only to the Robinson Mars trilogy, but to all the novels surveyed in this report: "The fact that a scenario for the full terraforming of Mars can be conceived within the parameter space of current planetological models, and without violating any known laws of physics, demonstrates that such an idea is, at least, feasible in principle. To bring such a project to fruition would require engineering capabilities greater than those of the present day, but not necessarily out of the question for a future civilisation several centuries ahead of our own." |
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| Feasibility |
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Requires New Technology |
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| Keywords |
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terraforming , engineering , skyhook , mars |
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Artist Name
Mark A. Garlick
Technique
- No Entry -
Title
Terraforming Mars
Description
Perhaps the Red Planet will one day become a Blue Planet, like Earth, if we can develop the appropriate terraforming technology.
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