Real Science Imagined Through Fiction

The Development of Terraforming during the Twentieth Century

By Pete Schmidt

{Note: This is one in Zeteo’s Fall 2014 series of pieces related to borders.}

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In the 1950s “hard science fiction” authors began to develop ideas and processes for changing other planets into habitable, Earth-like worlds. Named terraforming, the idea reflected the stalwart belief of mid-century American society in the ability to use science and technology to harness and control nature for the betterment of humankind. But what is most interesting in this case is that the concept and related principles of these fiction writers were subsequently explored and adopted by professional scientists and discussed in scientific journals and at scientific conferences.

This article will explore how the science of terraforming was created through the interaction between hard-science-fiction authors and professional scientists in ways that elided the boundaries between popular science, professional science, and science fiction. While science is often viewed as elite knowledge, and science fiction is often viewed as popular entertainment of no real scientific value, the development of terraforming shows that these boundaries are not so clear. Instead, the development of terraforming takes place in the overlap between the creative and the factual, the popular and the elite, the scholarly and the imaginative. The present piece will argue that hard science fiction has acted like an “intellectual commons”—a middle space between science and fiction that allows for a freedom and a creativity that may not be allowed in academic science and that embraces ideas and voices from professionals and non-professionals alike.[1] This article will demonstrate that the development of terraforming provides an example of how science and literature can feed off one another, use similar strategies to engage readers, develop new ideas, and communicate knowledge. The history of terraforming science can be viewed as a conversation that has taken place outside the perceived dichotomy of science and non-science A range of voices have shared, debated, and enhanced terraforming in an effort to envision the future of humanity in new imaginative ways.

Hard Science Fiction—Origins and Evolution

The key genre elements of hard science fiction date back nearly a century and were critical in providing a common space where ideas like terraforming could emerge. In 1937, John W. Campbell became the editor of the leading science-fiction magazine, Astounding Science Fiction, and sought to bring a more rigorous approach to the publication of science fiction. Though not entirely eschewing fantastic stories that had become the standard of the genre, he focused on recruiting authors with technological and scientific backgrounds to write stories aimed at an intelligent, well-educated audience. Campbell viewed his magazine as an avenue for scientists to examine and speculate upon a wider range of ideas than was allowed by the scientific academy. He envisioned scientists using the genre to create stories that functioned like thought experiments, exploring future possibilities of the problems and promises science and technology posed, and the impact these developments would have on humanity. Campbell and Astounding’s regular book reviewer and literary critic P. Schuyller Miller considered stories that attained the greatest scientific verisimilitude as the “hard core” of the science-fiction genre. Miller eventually dubbed such work “hard science fiction” in the 1950s. It was within this atmosphere that the first ideas of terraforming emerged as a means to convert other planets into Earth-like worlds to allow the human colonization of the solar system. Poul Anderson was one of the most innovative and influential of the authors to develop the idea.

Poul Anderson—First Terraforming Plans

In a writing career that spanned four decades, Poul Anderson became one of hard science fiction’s preeminent authors, publishing more than seventy novels and well over two hundred short stories. Anderson strove to attain scientific verisimilitude in his works through research and theoretical application. He was disappointed that science fiction largely depicted worlds just like Earth or that had a mishmash of Earth’s characteristics, and that descriptions of alien life showed a lack of research into and basic scientific understanding of conditions beyond the Earth.[2] Anderson insisted that achieving scientific veracity “does not take a degree in physics. It simply takes the basic knowledge of current scientific fact and theory . . . imagination and a willingness to work.”[3] Like Campbell, he argued that science fiction should be a place to expand and refine scientific ideas.[4]

Anderson was responsible for the earliest detailed terraforming schemes.[5] In a 1940 article in the Astrophysical Journal, Rupert Wildt had theorized that the Venusian atmosphere was largely composed of formaldehyde.[6] Anderson drew on this idea in his 1954 short story about the terraforming of Venus, “The Big Rain.” Here, he presented terraforming as a multi-stage process. First, wind-powered “airmakers” are installed in which the formaldehyde-laced Venusian atmosphere

was broken down and yielded its binding water molecules; the formaldehyde, together with that taken directly from the air, reacted with ammonia and methane—or with itself—to produce a whole series of hydrocarbons, carbohydrates, and more complex compounds for food, fuel and fertilizer; such carbon dioxide as did not enter other reactions was broken down by sheer brute force in an arc to oxygen and soot. The oxygen was bottled for industrial use; the remaining substances were partly separated by distillation—again using wind power, this time to refrigerate—and collected.[7]

As Anderson went on to describe, at the same time, genetically engineered bacteria released oxygen from the surrounding rock by consuming the carbon and silicon. Once these steps had properly prepared the atmosphere, hydrogen bombs would be exploded in the interior of the planet to reactivate volcanoes, venting gases, and “unthinkable tons” of water. The result was to be a rain that lasted for ten years and which, combined with the effects of lightning, would wash out the remaining poisons from the air and ground, creating a hydrological system on the surface of Venus. Such extensive details, drawing on the findings of chemists, atmospheric scientists, and geologists are the hallmark of hard science fiction.

In his 1958 novella, The Snows of Ganymede, Anderson continued to explore possibilities and simplified the process of terraforming. He introduced plans for Venus, Mars, and Ganymede, utilizing atomic explosions to alter the atmospheres and encourage a greenhouse effect. Here, too, Anderson relied on biological engineering to create organisms that could metabolize the poisons in the atmosphere and release oxygen to create a suitable environment for humanity.[8]

His 1959 short story “Sister Planet” reacts to the description of Venus as a vast, hot, landless ocean, with a carbon dioxide atmosphere.[9] Once again, Anderson proposed sowing genetically engineered organisms into the atmosphere. These organisms were to separate oxygen from the carbon dioxide through photosynthesis, forming a protective ozone layer, and eventually striking an atmospheric balance of elements identical to Earth’s.[10] Anderson’s approach, and especially his use of genetically modified organisms, would be greatly influential as terraforming was taken up and championed by Carl Sagan.

Carl Sagan—Professionalizing Terraforming

The work of Anderson and others marked the beginning of a conversation among science-fiction authors about the possibilities and promises of terraforming science.[11] This conversation was subsequently joined by the voice of professional science through the work of the theoretical physicist Carl Sagan, who came to well known for his popular science books. Sagan started reading science fiction at a young age, and it had a deep and long lasting influence on his professional life. Sagan has attributed his interest in space to the work of Edgar Rice Burroughs, whose pulp fiction stories he loved for their new and exciting ideas, alien life, and spirit of adventure. [12] He has recalled, “Such ideas, when encountered young, can influence adult behavior. Many scientists deeply involved in the exploration of the solar system (myself among them) were first turned in that direction by science fiction.”[13] Reflecting on his college years he explained, “It sustained me in my early years. I got a keen sense of the excitement of science from science fiction,” which kept [me] from “bow[ing] under the weight of conventional opinion.”[14]

Sagan’s first professional article, “The Planet Venus,” published in Science in 1961, offered refined calculations and observations supporting the theory that carbon dioxide in Venus’ atmosphere created a greenhouse effect responsible for its high atmospheric temperatures. After providing evidence for his claims, the article takes an unexpected turn, arguing that steps could be taken to “prepare Venus for comfortable human habitation.”[15] Sagan then proposes a plan strikingly similar to Poul Anderson’s, a plan that relies on biological organisms for altering the atmosphere and terraforming the planet.

In a passage that reads like a discourse from a scientist in a hard-science-fiction story, he explains the “micro-biological re-engineering” of Venus could occur if blue-green algae were seeded into the atmosphere. There they would break down the water and carbon dioxide through photosynthesis. As they drifted toward the surface, they would be “roasted,” releasing water into the atmosphere while their bodies fell as carbon onto the planet’s surface. This process would remove the abundant carbon dioxide in Venus’s atmosphere, dismantle the greenhouse effect, and, as in Anderson’s “Big Rain,” produce a deluge of rain, resulting in a hydrological system.

Such descriptive passages and speculative ideas that blurred the boundaries between professional science and hard science fiction were Sagan’s hallmark throughout his career, which spanned professional, popular, and science fiction writing. However, this was a trait that at times placed him at odds with, or at least outside of, the norms of the scientific community. His approach did not go unnoticed in the science-fiction community. John Campbell wrote to Sagan insisting his work was “precisely the sort of thing we want to present, of course—intelligent, careful analysis of non-terrestrial environments which could be life-supporting environments.” Campbell went on to explain to Sagan the important role he felt science fiction could play, explaining:

The present cultural attitude makes professional scientific journals very limiting in an important respect; scientists are not adequately free to speculate on possible systems in public, where scientists of other disciplines can cooperate in refining or expanding the suggested ideas. That is one very real service that science-fiction [sic] magazines such as Analog can serve, and which I try to make it serve.[16]

As we shall see, this is exactly the role hard science fiction played in the development of terraforming going forward.

Subsequently Anderson related and expanded upon Sagan’s ideas in his short story “To Build a World.” Here he lifted Sagan’s plan and packaged it almost verbatim into a conversation between two main characters. The male protagonist explains that Venus originally had

nitrogen, carbon dioxide, and a certain amount of water in the clouds. But the photosynthesizing algae grew exponentially once they’d been seeded in the upper atmosphere. They released oxygen; also, they kept sinking to lower levels where it was so hot they decomposed into carbon and water. The greenhouse effect dropped off until temperatures went below a hundred; and for ten years it rained without pause. Given liquid water, the Urey process operated, raw rock consumed still more CO-two [sic] and at last there was air that men could breathe.

Developing the ongoing conversation, Anderson then builds on Sagan’s idea, explaining, “Solar protons and ultraviolet radiation helped, too, especially in breaking down hydrogen compounds. In other words, a weak magnetic field is an asset to the terraformer.”[17]

Sagan continued to advance new terraforming plans for Mars in his 1973 bestselling popular science book The Cosmic Connection. This book was also the first time the term “terraforming” was used outside of a science-fiction context and marks Sagan’s acceptance of the science fiction term and rejection of his own, somewhat awkward “micro-biological re-engineering.” Drawing on recent information from the Mariner probes, Sagan concluded that the most reasonable terraforming plan for Mars was to alter the albedo (reflective quality) of the northern polar cap. Decreasing its albedo would trap more solar energy, melt the cap, and release its trapped gases, increasing the atmospheric pressure and improving the movement of heat across the planet, “which in turns heats the caps still further, and so on.” [18] Sagan’s plan was remarkably simple: to cover 6 percent of the cap with one millimeter of energy-absorbing material, such as carbon black, to create a net reduction of the albedo sufficient to trigger a gradual warming of Mars. He admitted, however, that there was no easy way to transport the required amounts of materials (eight to ten metric tons) such vast distances. To sidestep this problem, he suggested making the albedo-lowering substance out of microorganisms that could process the atmosphere through photosynthesis. This would simultaneously provide a dense covering of low albedo, significantly increase oxygen on the planet, and lower the amount of materials that had to be imported. Though no such microorganism existed, he echoed Poul Anderson in suggesting it could be genetically engineered to survive conditions on Mars.

Terraforming in the 1970s and 80s: Science in Fiction, Fiction in Science

The apparent simplicity and efficacy of Sagan’s plan excited working scientists, writers of popular science, and hard-science-fiction authors alike. A survey of these pieces shows a significant overlap in form and content between science and science fiction. For instance, science fiction author David Bergamini developed an eye-popping plan for Venus, which involved initiating a planet-wide chain reaction by hitting Venus with 1 million hydrogen-warhead missiles simultaneously. One reviewer explained that did not believe such a feat was possible, but admired it “for its pure audacity.”[19] Such fantastic plans had their counterparts within the scientific literature of the time, which promoted similarly “explosive” terraforming plans. For instance, Stanford lunar scientist Richard Vondrak argued it was possible to create an atmosphere on the moon through the vaporization of the lunar soil by “subsurface mining with nuclear explosives.”[20] Vondrak estimated that to achieve an oxygen-rich atmosphere, the detonation of 2 x 10¹¹ kilotons of TNT would be required. (I.e. 10⁴ times the total US stockpile of nuclear weapons.) Other articles appearing in the professional peer-reviewed The Journal of the British Interplanetary Society relied on similarly fantastic, though theoretically plausible, pieces of technology, including anti-matter engines, self-replicating machines, nano-machines, and fantastic schemes to turn planets into engines by harnessing their magnetic fields. [21]

Some of these works also contained science-fiction vignettes used to illustrate ideas and appeal to emotions by capturing the wonder of terraforming. Long passages dedicated to such descriptions are used extensively throughout NASA scientist James Oberg’s popular summary of terraforming science, New Earths. Professional geologist and science writer Stephen Gillett used imaginative vignettes focused on the sublime conditions of a terraformed Venus in his popular articles.[22] Professional astronomer Saul Adelman used the same technique in his popular work to describe the first stages of colonization on Mars.[23] Perhaps most notable is an article published in the Journal of the British Interplanetary Society by physicist and astronomer Alexander G. Smith. He used future tense rhetoric that placed terraforming in a fictional future frame, essentially creating a scientific article in the form of one long hard-science-fiction vignette. For instance, he predicted:

Before Venus can be converted to an Earth-like state, permanent settlements will exist on the Moon, and smaller bodies of the Solar System. Mars will have been changed to make it Earth-like, or preserved as a museum of the early history of the Solar System. A large population will live in space in artificial habitats, spacecraft and power stations.[24]

The Greening of Mars: Science Disguised as Fiction

The most refined and influential vision of terraforming came from the mind of James Lovelock, who worked for the Jet Propulsion Laboratories during the 1960s, designing life-detection experiments for the Mariner probes and helping to build many of the devices that would be flown on Viking missions. He was one of the first researchers to detect the presence of chlorofluorocarbons (CFCs) in Earth’s atmosphere and identify their dangerous effects. As a result of his experience on these projects he developed the so-called Gaia hypothesis, in concert with Lynn Margulis. The hypothesis claimed organisms interact with their surroundings to form a self-regulating system that contributes to the conditions for life on the planet. Put simply, organic life can make its environment suitable for more life. The idea sparked controversy and derision because it went against the conventional Darwinian view of the environment guiding the development of the organism.[25]

Lovelock continued to define and defend his idea in journal articles, in popular books, and in his 1984 hard-science-fiction novel about terraforming, The Greening of Mars.[26] The novel takes the form of a diary of a Martian colonist looking back on the steps taken to terraform Mars. Lovelock’s plan, explained through the narrator, requires the detonation on Mars of hundreds of ballistic missiles loaded with CFCs. The narrator recalls that these “super-greenhouse” gases rapidly raised the global temperatures and sublimated the polar ice, releasing more gases and thickening the atmosphere. Antarctic algae dispersed with the CFCs processed the Martian soil, preparing it for plant life and releasing more greenhouses gases that helped maintain the atmosphere after the CFCs dissipated. Then genetically engineered plants and microorganisms created a permanent Martian ecosphere and, following the Gaia hypothesis, created a feedback loop enabling more life to flourish and continue the process.

Adhering to hard-science-fiction genre standards, the fictional narrative is punctuated by explanations of scientific knowledge, such as summaries of modern understandings of the origins of life, explanations of the evolution of Earth’s atmosphere, the workings of the greenhouse effect, and a synthesis of the then current knowledge about conditions on Mars and its atmosphere. As with the overall development of terraforming science, the overlapping aspects of Lovelock’s text made it difficult to classify. One reviewer wrote: “It’s hard to tell if science or science fiction predominates in this book,” while another dubbed the overlap “science faction.”[27] Carl Sagan reviewed the book in the New York Times, calling it “a work of popular science attractively disguised as science fiction.”[28] Lovelock’s CFC plan greatly influenced the direction of terraforming in the scientific community, especially the ideas of one of its next prominent champions, Christopher McKay.

Christopher McKay

Throughout the late 1980s and early 1990s, NASA Ames planetary scientist Christopher McKay published articles in a wide array of professional and popular outlets. These articles offered viable plans for terraforming Mars and argued for the idea’s legitimacy.[29] McKay was part of a group of graduate students at the University of Colorado who were “motivated by Sagan’s original suggestion some years earlier of terraforming Venus.”[30] After graduating from the University of Colorado, McKay went on to become, throughout the 1980s, a leading advocate for terraforming Mars. Although he initially supported Sagan’s plan of triggering the greenhouse effect by lowering the polar caps’ albedo, McKay became an advocate of Lovelock’s CFC plan from The Greening of Mars. He refined Lovelock’s work, calculating that between 9 million and 1.4 billion tons of CFCs would be required to warm the planet to 40 degrees Celsius. This was far too much gas to ship, but easy enough to produce in factories on the surface. Massive orbiting solar mirrors could also be used to warm the polar caps. Using these steps, McKay projected Mars could be warm in 200 years, “with a thick carbon dioxide atmosphere and extensive vegetation. There are no large animals, but humans can survive with scuba gear alone.”[31] Lovelock’s Gaia hypothesis indicated technology could be used to start the changes; the ultimate stability of the system would rely on planetary biology.[32] Like authors before him, McKay, too, turned to the humble microorganism to redesign the Martian ecosphere. His research showed that the bacteria Beijerinckia lacticogenes was capable of thriving under Mars-like conditions, but genetically modified microorganisms might be more effective.[33]

1990s- Wider Audience and Wider Acceptance

Our story now reaches a key moment, when the idea of idea of terraforming gains significant and wide-spread legitimacy and credibility within the scientific community, while at the same time maintaining its presence in hard science fiction. In June of 1991, NASA hosted a two-day conference at the Ames Research Center on terraforming Mars. The conference focused on ways Mars could be altered through the greenhouse effect.[34] Three participants at the conference, Christopher McKay, Owen Toon, and James Kasting, published their conclusions in a 1991 article in the British journal Nature, marking a significant advancement of the idea into the realm of professional science. They proposed a plan similar to the one outlined by Lovelock—using CFCs to warm the planet and then introducing plants to produce a breathable atmosphere within 100,000 years. This publication received worldwide attention in the popular press, prompting the publication of more than one hundred professional and popular articles on terraforming by the year 2000.

McKay’s work continued to span the gap between science and hard science fiction. He incorporated Lovelock’s plans and cited the hard-science-fiction novel in his scientific publications. His articles credited other science-fiction authors for advancing the idea and indicated the important role science fiction had in further development of the idea. “As science now approaches the ‘how’ of terraforming, science fiction must continue to explore the ‘why.’”[35] Further, McKay echoed the colonizing visions of science-fiction authors, such as Arthur C. Clarke, Robert Heinlein, and Jerry Pournelle—that terraforming was a critical process for any Martian colony to be self-sufficient, so the benefits of terraforming to the Martians “would be quite tangible—the long-term survival of their civilization.”[36]

Outside of McKay’s professional work, perhaps the most important and influential work on terraforming from the 1990s has been Kim Stanley Robinson’s Mars Trilogy, which presents an epic story of the terraforming of Mars from the earliest settlers to the flourishing of an entirely new Martian culture.[37] It draws heavily on contemporaneous scientific data about Mars to create the most realistic and detailed terraforming presentation of all the hard-science-fiction works. The complex plan draws on previous schemes, like those of Sagan (using carbon dust on the poles), Lovelock (using biology to help reform the atmosphere), and Asimov (using an ice asteroid to add water to the atmosphere). Robinson also introduced a new technological step, using hundreds of thousands of wind-driven generators to release heat into the atmosphere, aiding in triggering the greenhouse effect. Robinson’s series was met with critical acclaim and brought a fully realized vision of terraforming to a whole new generation of readers, continuing to build interest in the idea. And the professional scientific community’s and science-fiction authors’ common interest in terraforming has continued to flourish in the twenty-first century. For instance, in March 2004, NASA Ames, along with the Science Fiction Museum and Hall of Fame, cosponsored a conference on terraforming. This demonstrated scientific professionals’ willingness to include science-fiction authors as vital and relevant members in the terraforming dialogue.

Conclusion

This examination of hard science fiction and the concept of terraforming challenges the idea of there being strict boundaries between science and non-science. Notwithstanding its speculative and “science fiction” nature, the idea of terraforming took hold among some scientists. While it could be argued that scientists used their credibility to establish terraforming as a legitimate area of scientific inquiry, they never laid “claim” to terraforming in any meaningful way. What is particularly interesting about the half century and more of evolving conversation is how the hard-science-fiction authors continued to develop terraforming in concert with scientists, and how scientists seemed to keep the imaginative ideas of the science-fiction writers in view. The clearest example of this is that the term terraforming has remained the common name for the process despite introductions by some scientists of different terms for the process, such as planetary engineering, microbiological engineering, or biological ecosynthesis.

In this instance, it is clear that hard science fiction and science have overlapped, negotiated with, and informed one another. It has not been just a case of one influencing the other. The boundaries between the two have remained blurred because of the particular locations in which their analyses occurred, but very often elements have been shared between the two fields. Like practicing scientists, hard-science-fiction authors have based their ideas on scientific facts and have carefully extrapolated from these facts. They have published their ideas and discussed them in open forums, such as letters columns, conferences, and articles. Authors have been held to standards of scientific explanation and authority in these forums, as readers, reviewers, and other authors have engaged in unearthing logical fallacies or identifying incorrect scientific information in the stories.

Likewise, terraforming scientists have used elements of hard science fiction. They have relied on plausible scientific and technological developments to advance their terraforming plans, and a few even published hard-science-fiction works. Scientific researchers have also utilized hard-science-fiction elements within their professional publications as rhetorical devices to increase plausibility and explain elements that might otherwise be difficult to grasp. Terraforming researchers have described their work in terms similar to hard-science-fiction authors, because they, too, have been projecting a future as yet unknown, but based on what is known. What particularly demonstrates this intersection of fiction and science is the engagement of terraforming researchers who have drawn liberally from hard-science-fiction authors, citing and explaining their ideas in professional and popular works alike, alternately criticizing, praising, or amending them as they did ideas of professional scientists.

What do we make of this overlap? This is where Katherine Pandora’s idea of the “intellectual commons” is useful. As a genre, hard science fiction has played a key role as such a commons—a place where ideas circulate without regard for education, occupation, or specific disciplinary boundaries and proprieties. Here the notions of “popular,” “scientific,” and “science fiction” have become largely irrelevant. The resulting collaboration between scientists and non-scientists has allowed ideas to be developed, tested, and refined. Importantly, the commons allows modes of communication that professional strictures inhibit and has provided opportunities to engage in speculation at odds with the rhetorical norms of academic science. Both authors and fans alike believe that such speculation has a role to play, as scientists and the public envision possibilities of moving further into outer space.

Just as terraforming can ultimately be removed from the constraining labels of science or non-science, so can its history. Here literature and science exist in a close and complementary way, illustrating a broad and interdisciplinary public inquiry intent on considering the future of Earth’s population and humanity’s relationship to nature and technology within that future.

*     *     *

Pete Schmidt holds a PhD in the History of Science and Technology from the University of Minnesota and an MA in Interdisciplinary Humanities from Arizona State University. An Assistant Professor of Humanities at Grossmont College in San Diego, his primary research interests pertain to forms and ideas of science and technology that exist in the margins, boundaries, and other in-between places of society.

Endnotes

[1] This idea of an intellectual commons comes from Katherine Pandora, “Knowledge Held in Common: Tales of Luther Burbank and Science in the American Vernacular,” Isis 92 (2001): 484-516.

[2] Poul Anderson, letter to Lawrence Ashmead, April 21, 1965, Papers of Poul Anderson Huntington Library, San Marino, California.

[3] Poul Anderson, “The Creation of Imaginary Worlds: The World Builders Handbook and Pocket Companion,” in Science Fiction Today and Tomorrow, ed. Reginald Bretnor (Baltimore: Penguin Books, 1974), 107.

[4] Anderson, letter to Lawrence Ashmead, March 31, 1970, Papers of Poul Anderson.

[5] Hal Clement originally coined the term “terraforming” in his short story “Collision Orbit,” Astounding Science Fiction, July, 1942, though early manifestations of the idea can be found in Olaf Stapledon’s novel Last and First Men (London: Methuen Publishing, 1930). Neither author, however, makes an attempt to rigorously explain the process.

[6] Rupert Wildt, “On the Possible Existence of Formaldehyde in the Atmosphere of Venus,” Astrophysical Journal 92 (1940): 247.

[7] Poul Anderson, “The Big Rain,” Astounding Science Fiction, October 1954, quote from 21-22.

[8] Poul Anderson, The Snows of Ganymede (New York: Ace Books, 1958), 29-31, 57.

[9] Donald Menzel and Fred Whipple, “The Case for H2O Clouds on Venus,” Publications of the Astronomical Society of the Pacific 67, no. 396 (1955), 161-68.

[10] Poul Anderson, “Sister Planet,” Satellite, May, 1959, 4-20.

[11] Other science-fiction stories that contain terraforming elements form this period include: Henry Kuttner Fury (1947); Robert Heinlein Farmer in the Sky (1950); Arthur C. Clarke The Sands of Mars (1952); Isaac Asimov, “The Martian Way,” Galaxy, November, 1952, 4-41; Walter M. Miller, “Crucifixus Etiam,” Astounding Science Fiction, February, 1953, 97-113; James Blish, The Seedling Stars (1957); Cordwainer Smith, “When the People Fell,” Galaxy April, 1959, 147-51.

[12] Henry S.F. Cooper, “A Resonance with Something Alive,” in Conversations with Carl Sagan, ed. Tom Head (Jackson: University Press of Mississippi, 2006), 27.

[13] Carl Sagan, Broca’s Brain: Reflections on the Romance of Science (New York: Random House, 1979), 145. Here Sagan provided a reflection on the impact of science fiction on his life and criticisms of contemporary science fiction and illustrates knowledge of the work of many terraforming authors including Clarke, Heinlein, Anderson, Miller, Asimov, and Williamson.

[14] David Swift, SETI Pioneers: Scientists Talk About Their Search for Extraterrestrial Intelligence (Tucson: University of Arizona Press, 1990), 212-13.

[15] Carl Sagan, “The Planet Venus,” Science 133 (1961): 857.

[16] Perry Chapdelaine, Tony Chapdelaine, and George Hay, eds., The John W. Campbell Letters (Franklin: AC Projects, 1985), 513.

[17] Poul Anderson, “To Build a World,” Galaxy Science Fiction, June, 1964, 27.

[18] Carl Sagan, “Planetary Engineering on Mars,” Icarus 20 (1973): 513-14.

[19] David Bergamini, Venus Development (New York: Popular Library, 1976); Robert Chilson, “Venus Development,” Delap’s F&SF Review March 1977, 34.

[20] R.R. Vondrak, “Creation of an Artificial Atmosphere on the Moon,” Advances in Engineering Science, vol. 3 NASA CP-2001 (1976), 1217.

[21] Saul Adelman, “Can Venus Be Transformed into an Earth-Like Planet?” Journal of the British Interplanetary Society 35 (1982): 4-6; Robert Freitas Jr, “Terraforming Mars and Venus Using Machine Self-Replicating Systems,” Journal of the British Interplanetary Society 36 (1983): 139-42; Martyn Fogg, “The Creation of an Artificial, Dense Martian Atmosphere: A Major Obstacle to the Terraforming of Mars,” Journal of the British Interplanetary Society 42 (1989): 580. Martyn Fogg, “The Terraforming of Venus,” Journal of the British Interplanetary Society 40 (1987): 551-64.

[22] For example Stephen Gillett, “The Postdiluvian World,” Analog 11 (1985): 40.

[23] Saul Adelman, Bound for the Stars (Englewood Cliffs: Prentice-Hall, 1981), 145-48.

[24] A.G. Smith, “Transforming Venus by Induced Overturn” Journal of the British Interplanetary Society 42 (1989), 571.

[25] J. E. Lovelock, Homage to Gaia: The Life of an Independent Scientist (Oxford: Oxford University Press, 2000), 254-55.

[26] James Lovelock, The Greening of Mars (New York: Warner Books, 1984).

[27] Margery Coombs, “Review of the Greening of Mars,” Library Journal September 15, (1984): 1764; A.E. Smith, Mars: The Next Step (London: Taylor and Francis, 1989), 125, 128.

[28] Carl Sagan, “The Terraformers Are Coming,” New York Times Book Review, January 6, 1985, 6.

[29]Christopher McKay, “On Terraforming Mars,” Extrapolation 23.4 (1982): 309-14; “Terraforming Mars,” Journal of the British Interplanetary Society 35 (1982): 427-33; “Terraforming: Making an Earth of Mars,” The Planetary Report 7.6 (1987): 26-27; “Should We Implant Life on Mars?” Scientific American 263.6 (1990): 144.

[30] “Meet the Scientist: Dr. Chris McKay,” accessed July 2008 via http://chapters.marssociety.org.

[31] Christopher McKay, “On Terraforming Mars,” Extrapolation 23.4 (1982): 312-13.

[32] Christopher McKay, “Terraforming Mars,” Journal of the British Interplanetary Society 35 (1982): 312; McKay, “Terraforming Mars,” 430-31.

[33] McKay, “Terraforming Mars,”431; Christopher McKay, “Terraforming: Making an Earth of Mars,” The Planetary Report 7.6 (1987): 27.

[34] NASA Workshop on Terraforming Mars, Ames Research Center, June 1991.

[35] McKay, “On Terraforming Mars,” 309.

[36] McKay, “Terraforming: Making an Earth of Mars,” 27.

[37] Kim Stanley Robinson, Red Mars (New York: Bantam, 1993); Green Mars (New York: Spectra, 1995); Blue Mars (New York: Spectra, 1997).