A City on Mars

A City on Mars Plot Summary

Introduction

When we gaze at the stars, many of us wonder if humans might someday live among them. Science fiction has filled our imaginations with gleaming space stations, domed cities on Mars, and intrepid explorers venturing to distant worlds. These visions seem increasingly plausible as private companies launch rockets and national space agencies announce ambitious plans to return to the Moon and journey to Mars. Yet the reality of establishing permanent human settlements beyond Earth involves challenges far more complex than simply building better rockets or more spacious habitats. The human body evolved specifically for Earth conditions, with its particular gravity, atmosphere, and magnetic field. Remove these familiar parameters, and our biology faces profound challenges that technology alone cannot easily solve. From radiation damage to bone loss, reproduction difficulties to psychological strain, the obstacles to thriving beyond Earth are formidable. This book examines the scientific realities behind space settlement dreams, exploring not just the technological hurdles but the biological, psychological, legal, and economic challenges that rarely feature in popular discussions. Understanding these realities isn't about abandoning our cosmic aspirations, but rather approaching them with the knowledge needed to create sustainable human communities among the stars.

Chapter 1: The Human Body in Space: Biological Challenges

The human body is exquisitely adapted to Earth's environment after millions of years of evolution. When we venture into space, this finely tuned biological machine encounters conditions it was never designed to handle. Perhaps the most immediate challenge is microgravity, which triggers a cascade of physiological changes throughout the body. Without gravity's constant pull, bones lose calcium and minerals at an alarming rate – approximately 1-2% per month – leading to a condition similar to osteoporosis. Muscles, no longer needed to work against gravity, rapidly atrophy despite rigorous exercise regimens. Even after six-month missions on the International Space Station, returning astronauts often struggle to walk and frequently fall during their first days back on Earth. Fluid redistribution represents another significant challenge in microgravity. On Earth, gravity pulls bodily fluids downward, but in space, these fluids shift toward the upper body, causing what astronauts call "puffy face, bird legs" syndrome. This fluid shift increases pressure in the head and can lead to a serious condition called Spaceflight Associated Neuro-ocular Syndrome (SANS), which affects vision. Studies show that over 60% of astronauts experience vision changes during long-duration missions, with some effects persisting long after their return to Earth. The cardiovascular system also undergoes significant changes – the heart, no longer working against gravity to pump blood upward, becomes deconditioned, potentially leading to problems upon return to Earth's gravity. Radiation exposure presents perhaps the most serious long-term health risk for space travelers. Earth's magnetic field and atmosphere shield us from the harmful radiation that permeates space, but astronauts beyond this protection face constant bombardment from cosmic rays and solar particles. This radiation can damage DNA, increase cancer risk, and potentially cause neurological problems. A round-trip Mars mission using current technology would expose astronauts to radiation doses approaching or exceeding NASA's career lifetime limits. For permanent settlers, the cumulative effects of this radiation exposure over years or decades remain largely unknown but deeply concerning. The immune system also functions differently in space, with studies showing decreased immune cell activity and reactivation of dormant viruses. Wounds heal more slowly, and bacteria appear to become more virulent in microgravity. These changes raise serious concerns about long-term health in space settlements, particularly regarding infectious disease management. Even common medical procedures become problematic – blood doesn't pool as expected during surgery, medications may behave differently, and emergency evacuation to Earth would be impossible from distant settlements on Mars or beyond. Sleep disturbances compound these physiological challenges. Astronauts on the International Space Station witness sixteen sunrises and sunsets daily as they orbit Earth every 90 minutes, thoroughly disrupting their circadian rhythms. Many rely on medications to maintain healthy sleep patterns. The psychological stress of confinement, isolation, and the constant awareness of danger further impacts sleep quality. For long-duration missions or permanent settlements, establishing healthy sleep patterns would be essential for both physical health and cognitive performance. These biological challenges aren't merely inconveniences but fundamental obstacles to long-term human presence in space. While technological solutions like artificial gravity through rotation or enhanced radiation shielding might mitigate some problems, others may require biological adaptations that could take generations to develop. Understanding these challenges is crucial for designing habitats, medical systems, and support technologies that can sustain human life beyond the protective cradle of Earth.

Chapter 2: Reproduction Beyond Earth: Can Humans Create New Life in Space?

For a space settlement to truly succeed, humans must eventually be able to reproduce there. This fundamental aspect of human existence faces extraordinary challenges beyond Earth that receive surprisingly little attention in discussions about Mars colonies or space habitats. The process of human reproduction – from conception through fetal development to birth and childhood growth – evolved specifically for Earth's gravity, radiation environment, and atmospheric conditions. Remove these familiar parameters, and we enter uncharted biological territory with profound implications for the future of our species. Conception itself may be problematic in space environments. While no human pregnancies have been attempted in space, experiments with animals raise serious concerns. Studies with mice aboard the International Space Station have shown alterations in sperm motility and fertilization processes. The complex cellular choreography of conception relies partly on gravity to orient cells and facilitate their interaction. Without this orienting force, the fundamental first step of reproduction may be compromised. Even if conception occurs, the early development of an embryo – which depends on precise cellular divisions and migrations – could be severely disrupted in microgravity or the partial gravity of Mars or the Moon. Pregnancy in space presents even greater concerns. The developing fetus relies on gravity for proper orientation and development of the vestibular system, which governs balance and spatial awareness. Animal studies in simulated microgravity have shown abnormal development of the inner ear and balance organs. Additionally, the increased radiation exposure in space could cause devastating mutations in rapidly dividing fetal cells. The human placenta, which filters nutrients and waste between mother and fetus, might function differently without gravity's influence on blood flow. These factors together suggest that pregnancy in space could result in developmental abnormalities incompatible with healthy development. The birth process itself evolved with gravity as a crucial component. On Earth, gravity helps guide the baby through the birth canal and assists in the expulsion of placental tissues after delivery. Without this force, childbirth would require completely new techniques and technologies. Some researchers have proposed rotating chambers that simulate gravity during pregnancy and birth, but these remain theoretical and would require enormous energy resources to maintain for months at a time. Emergency medical interventions during complicated births would be severely limited in isolated space settlements, potentially endangering both mother and child. Even if a healthy birth occurs, raising children in space presents further challenges. Bone density and muscle development in growing children depend on resistance against gravity. Without this resistance, children born in space might develop with brittle bones and weak muscles that could never adapt to Earth's gravity. Their cardiovascular systems would likely be underdeveloped as well. Some researchers speculate that children raised entirely in low-gravity environments might become a distinct branch of humanity – physiologically incapable of ever visiting their ancestral planet. The psychological development of children who never experience Earth's open spaces, diverse ecosystems, and natural rhythms remains another significant unknown. The ethical implications of space reproduction are equally daunting. Is it morally justifiable to bring new life into an environment where normal development may be impossible? Would children born with space-induced abnormalities consider their existence a scientific achievement or an ethical failure? These questions have no easy answers, yet they must be addressed before any permanent, self-sustaining human settlement beyond Earth can be established. The dream of becoming a multi-planetary species ultimately depends not just on our ability to survive in space, but to create and nurture new generations there.

Chapter 3: Closed Ecosystems: The Challenge of Self-Sustaining Habitats

Creating a sustainable habitat in space means replicating Earth's natural cycles in miniature. On our home planet, plants convert carbon dioxide to oxygen, animals and humans do the reverse, and decomposers break down waste into nutrients for new growth. In space, these processes must be engineered into what scientists call a "closed-loop life support system" – where virtually nothing is wasted and resources continuously cycle through the habitat. This represents one of the most complex challenges of space settlement, yet receives far less attention than rocket development or habitat construction. Water recycling forms the foundation of any closed ecosystem. On Earth, the water cycle purifies and distributes water through evaporation, condensation, and precipitation. In space habitats, this natural process must be replicated through technological systems. The International Space Station currently recovers about 90% of its water – including urine, humidity from breath, and even sweat – through a complex filtration system. Astronauts sometimes joke about "yesterday's coffee becoming today's coffee," but this efficient recycling is essential for space settlement. Future systems will need to push recovery rates even higher, approaching 99% to minimize resupply needs from Earth. Even small leaks or inefficiencies in water recycling could threaten the viability of a settlement over time. Food production presents an even greater challenge. While the ISS has successfully grown small quantities of lettuce and other vegetables, creating a complete diet requires substantial growing area and diverse crops. Estimates suggest that each person requires between 30-50 square meters of growing space for a plant-based diet. Animal protein is even more resource-intensive, leading many space settlement designs to focus on efficient alternatives like insects, which convert feed to protein much more efficiently than traditional livestock. The most ambitious closed ecosystem experiment on Earth, Biosphere 2, demonstrated the difficulty of food production even with 3.14 acres under glass. The eight inhabitants experienced significant weight loss despite devoting much of their time to agriculture. Waste management goes beyond simple disposal – in a closed system, waste becomes a resource. Human solid waste contains valuable nutrients that, properly processed, can feed plants. Carbon dioxide exhaled by settlers becomes essential for plant growth. Even packaging materials and worn-out equipment must be designed for recycling or repurposing. The most successful space habitats will likely be those that most effectively turn "waste" into resources. This requires not just technological solutions but cultural adaptations to view resources differently than we do in Earth's open system, where materials can be extracted, used, and discarded. Maintaining atmospheric balance represents another crucial aspect of closed ecosystems. Plants and algae can convert carbon dioxide to oxygen, but achieving the precise balance needed for human health requires careful management. In Biosphere 2, oxygen levels unexpectedly declined during the two-year experiment, eventually requiring external supplementation. The cause was later identified as microbes in the enriched agricultural soil consuming oxygen and concrete in the structure absorbing carbon dioxide. This illustrates how even well-designed closed systems can experience unexpected interactions among their components. Space habitats would need robust monitoring systems and multiple redundancies to maintain safe atmospheric conditions. The psychological aspects of living in closed ecosystems cannot be overlooked. Humans evolved in open environments with natural light cycles, varied landscapes, and diverse sensory experiences. Confined habitats with artificial lighting, recycled air, and limited variety can induce psychological stress over time. Biosphere 2 participants reported significant challenges adapting to their enclosed world, despite its relatively large size. Space habitats would need to incorporate design elements that address these psychological needs – perhaps through virtual reality, carefully designed lighting systems, or interior spaces that create an illusion of openness. The most technically perfect habitat will fail if its inhabitants cannot maintain their mental health within its walls.

Chapter 4: Mars vs. Moon: Comparing Potential Settlement Locations

The Moon and Mars represent humanity's most viable options for establishing settlements beyond Earth, yet they offer dramatically different environments with unique advantages and challenges. The Moon, just three days' journey from Earth, provides relative accessibility for both emergency evacuations and supply deliveries. Its proximity allows real-time communication with Earth, with only a 1.3-second delay each way. The lunar surface contains valuable resources, particularly water ice in permanently shadowed craters near the poles, which could be processed into drinking water, breathable oxygen, and rocket fuel. Some areas near the lunar poles experience "eternal light," receiving nearly constant sunlight for solar power generation. However, the lunar environment presents severe challenges for human habitation. The Moon has no atmosphere to speak of, offering no protection from radiation or micrometeorites. Surface temperatures swing wildly from 260°F (127°C) during the two-week lunar day to -280°F (-173°C) during the equally long lunar night. The lunar surface is covered in regolith – fine dust particles with sharp, jagged edges that cling to everything through electrostatic forces. This dust poses serious respiratory hazards and can damage equipment through its abrasive nature. Perhaps most significantly, the Moon lacks many elements essential for life, particularly carbon, which makes up about 18% of the human body and is crucial for growing food. Any lunar settlement would need to import these elements from Earth or extract them from the minimal amounts present in lunar soil. Mars offers a more Earth-like environment in several respects. Its day (called a sol) is remarkably similar to Earth's at 24 hours and 37 minutes, helping maintain human circadian rhythms. The planet experiences seasons due to its axial tilt, creating somewhat familiar patterns of environmental change. The Martian atmosphere, while thin, provides some protection against radiation and micrometeorites. Most importantly, Mars contains all the elements necessary for life – carbon, hydrogen, nitrogen, and oxygen – though many are locked in forms that would require processing. Water exists as ice at the poles and possibly as subsurface liquid in some regions. The Martian gravity, at about 38% of Earth's, might be sufficient to prevent some of the worst health effects of microgravity. Yet Mars presents its own unique challenges. The journey to Mars takes 6-9 months with current technology, making emergency returns impossible and creating significant logistical challenges for establishing and maintaining settlements. The Martian atmosphere, while present, is 95% carbon dioxide and too thin to breathe or provide meaningful protection from cosmic radiation. The soil contains perchlorates – toxic chemicals that would need to be removed before growing food. Global dust storms can engulf the entire planet, blocking solar power for weeks or months. Communication delays range from 4 to 24 minutes each way depending on the planets' relative positions, making real-time conversation with Earth impossible and complicating remote operation of systems. Both locations would require settlers to live primarily underground or in heavily shielded habitats to protect against radiation. Neither offers easy access to the resources needed for industrial civilization – both would require enormous technological infrastructure to extract and process raw materials into usable forms. The economic case for settlement remains challenging for both locations, as neither contains easily accessible resources valuable enough to justify the enormous cost of extraction and transport back to Earth. Tourism, scientific research, and the intrinsic value of expanding human presence beyond Earth represent the most likely justifications for early settlements. The choice between these destinations ultimately depends on settlement goals. The Moon offers a proving ground closer to Earth where technologies and techniques can be tested before committing to more distant locations. Mars provides a more resource-rich environment that might better support long-term, self-sustaining settlement. Either choice represents an unprecedented challenge for human ingenuity and adaptation, requiring us to create habitable environments where none naturally exist.

Chapter 5: Space Law: Who Owns the Stars?

As humanity extends its reach beyond Earth, we enter a legal wilderness where traditional concepts of sovereignty, property, and governance face unprecedented challenges. The legal framework governing space activities was largely established during the Cold War, when only superpowers had access to orbit and the primary concern was preventing military confrontation in this new domain. Today, as private companies and numerous nations develop space capabilities, these aging legal structures are increasingly strained by new realities. The cornerstone of space law remains the 1967 Outer Space Treaty (OST), ratified by 111 countries including all major spacefaring nations. This treaty establishes space as a commons – belonging to all humanity rather than subject to national appropriation. Article II explicitly states that "outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means." This principle seemed straightforward when only government agencies ventured beyond Earth, but becomes problematic in an era of commercial space exploitation. If no nation can claim territory in space, how can companies secure the rights needed to justify massive investments in space resources? This question becomes particularly acute regarding resource extraction. The OST prohibits territorial claims but remains ambiguous about whether resources extracted from celestial bodies can become private property. The United States and Luxembourg have passed national legislation explicitly permitting their citizens and companies to own resources they extract from asteroids or planets, arguing this doesn't constitute territorial appropriation. Other nations, particularly developing countries, view this interpretation as an end-run around the treaty's commons principle, potentially allowing wealthy nations to monopolize space resources while technically observing the letter of the law. The 1979 Moon Treaty attempted to address these issues by establishing space resources as the "common heritage of mankind" and calling for an international regime to govern their exploitation with equitable sharing of benefits. However, this treaty has been ratified by only 18 countries, none of them major spacefaring nations. The United States, Russia, China, and other space powers rejected its constraints on resource utilization, effectively rendering it irrelevant to current space development. This creates a troubling legal vacuum as nations and companies prepare for lunar mining operations that could target valuable resources in permanently shadowed craters or the "peaks of eternal light" near the lunar poles. Governance of permanent settlements presents even thornier issues. If humans establish colonies on Mars or large space stations, what laws will govern them? Under the OST, nations retain jurisdiction over their registered space objects and personnel, but this becomes unwieldy for multi-national settlements or those seeking independence. Would Mars colonists remain citizens of their Earth nations indefinitely? Could they declare independence, and if so, how would Earth nations respond? History suggests that distant colonies eventually seek self-governance, but the OST provides no mechanism for this transition. The legal challenges extend to environmental protection as well. No comprehensive framework exists to prevent contamination of scientifically valuable sites or to preserve areas of natural beauty on other worlds. Without agreed-upon "space environmental law," the first entities to reach valuable locations may irreversibly alter them before humanity can collectively decide their proper use. The legal principle of "first come, first served" could lead to a chaotic land rush with destructive consequences for scientific research and future generations. Resolving these legal uncertainties requires international cooperation at a time when geopolitical tensions are rising, presenting perhaps the greatest non-technical barrier to establishing human presence beyond Earth.

Chapter 6: The Economics of Space: Can Settlements Be Self-Sufficient?

The economic viability of space settlement hinges on a fundamental question: Can extraterrestrial communities generate sufficient value to sustain themselves without constant support from Earth? Popular narratives often focus on resource extraction – mining asteroids for precious metals or extracting helium-3 from the lunar surface for fusion energy. However, the economic reality proves far more complex and challenging than these optimistic scenarios suggest. Mining space resources faces severe economic hurdles. While asteroids indeed contain valuable metals like platinum and gold, the cost of reaching them, extracting materials, and returning these resources to Earth markets remains prohibitive with current technology. The delta-v (change in velocity) required to reach most asteroids and return materials to Earth demands enormous energy expenditures that could exceed the value of extracted resources. Even for near-Earth asteroids, which require less energy to reach, the technology for extracting, processing, and transporting materials in space remains theoretical and would require massive upfront investment. The most economically viable space resources may be those used in space itself – particularly water ice that could be processed into rocket propellant, creating a "gas station in space" that reduces the cost of further exploration. The concept of in-situ resource utilization (ISRU) – using local materials rather than importing from Earth – represents a critical component of settlement economics. On the Moon, regolith could potentially be processed to extract oxygen, silicon for solar panels, and metals for construction. Mars offers more abundant resources, including all elements necessary for life and industry. However, converting these raw materials into usable forms requires substantial infrastructure – mining equipment, processing facilities, manufacturing plants – all of which must first be transported from Earth at enormous expense. This creates a bootstrap problem: creating self-sustaining economies requires massive infrastructure, but building that infrastructure requires either enormous upfront investment or a gradual bootstrapping process that may take decades or centuries. Energy production represents another economic challenge. Solar power works well in Earth orbit and on the lunar surface but becomes less efficient on Mars (which receives about 60% of Earth's solar energy) and useless during Martian dust storms or the two-week lunar night. Nuclear power offers greater reliability but introduces additional safety and waste management concerns. Any settlement must incorporate redundant power systems and extensive energy storage capabilities to survive inevitable interruptions. The cost of establishing and maintaining these energy systems adds significantly to the economic burden of settlement. The most viable near-term space economic activities may be service-based rather than resource extraction. Satellite communications, Earth observation, and space tourism already generate billions in revenue without requiring settlement or large-scale resource utilization. Scientific research stations, similar to Antarctic bases, represent another model where the value produced is knowledge rather than physical commodities. However, these activities primarily support Earth's economy rather than establishing self-sustaining space economies. They might justify outposts but not large-scale settlement. Perhaps the most realistic economic model for initial space settlement would be the company town, where a single entity controls all aspects of life and commerce. This approach dominated early resource extraction in remote locations on Earth, from mining towns to oil fields. However, company towns historically created problematic power imbalances between employers and workers, raising serious concerns about governance, rights, and quality of life in isolated space habitats where alternatives don't exist. The economic realities of space settlement may thus conflict with idealistic visions of space as a domain of freedom and opportunity, at least in the early stages of development.

Chapter 7: Space Psychology: Mental Health in Isolated Environments

Living in space means confronting profound isolation unlike anything experienced on Earth. Even in the most remote Antarctic research stations, help is potentially days away – in space, rescue could be months or years distant, if possible at all. This reality creates a unique psychological burden that astronauts call "the overview underfoot" – the constant awareness that Earth, with all its resources and support systems, is unreachably distant. Understanding and addressing the psychological challenges of space habitation is crucial for any successful long-term settlement. Space habitats are necessarily confined environments where privacy is limited and social dynamics are intensified. On the International Space Station, astronauts have reported irritation with crewmates' habits becoming magnified over time – the sound of someone eating, their personal hygiene routines, or communication styles can become sources of significant tension. Studies of isolated environments show that small annoyances can escalate into serious conflicts when people cannot escape each other's presence. The phenomenon of "third-quarter syndrome" – where tension and conflict peak during the third quarter of a mission's duration – has been observed in Antarctic winter-over crews, submarine missions, and space simulations. Managing these interpersonal dynamics becomes crucial for settlement success. The sensory environment of space habitats presents another challenge. The constant mechanical background noise, artificial lighting, recycled air, and limited variety of foods create a sensory monotony that humans find wearing over time. Our brains evolved to process changing environments and novel stimuli – when these are absent, people report feelings of boredom, irritability, and even perceptual distortions. Some astronauts have described experiencing time dilation, where days seem to stretch endlessly. Habitat designers must consider these psychological needs, incorporating varied environments, natural light cycles, and sensory diversity to maintain mental health. Communication delays compound these psychological stresses. A message to Mars would take between 4 and 24 minutes to arrive, depending on the planets' relative positions. This makes real-time conversation impossible and creates a profound sense of disconnection from loved ones and support systems on Earth. Future settlers would need to develop new communication norms and psychological coping strategies for this delayed interaction. The inability to receive immediate assistance during emergencies adds another layer of psychological burden – settlers must be prepared to handle crises independently, knowing that guidance from Earth will arrive too late to help with immediate decisions. Sleep disturbances are nearly universal among astronauts. The unnatural light cycles, noise, and excitement or stress of the mission all contribute to poor sleep quality. On the ISS, astronauts witness 16 sunrises and sunsets daily as they orbit Earth, thoroughly disrupting natural circadian rhythms. For long-duration missions or permanent settlements, establishing healthy sleep patterns would be essential for both psychological wellbeing and cognitive performance. Habitat design must incorporate lighting systems that mimic Earth's day-night cycle and provide adequate sound insulation for sleeping quarters. Meaningful work and purpose represent perhaps the most important psychological factors for long-term settlement success. Humans need to feel that their activities have value and contribute to something larger than themselves. In the confined environment of a space habitat, where many tasks may be routine maintenance, creating a sense of purpose becomes crucial. The most successful space settlements might ultimately be those that best address these human psychological needs, not just the engineering challenges of survival. As one NASA psychologist noted, "We're not just sending hardware to Mars – we're sending humanity, with all its psychological complexities."

Summary

The scientific reality of space settlement reveals a profound paradox: while technology has made accessing space easier than ever before, the biological, psychological, and social challenges of living beyond Earth remain formidable. Our bodies, evolved specifically for Earth's gravity and protected by its magnetic field and atmosphere, struggle with the harsh realities of space environments. From bone loss to radiation damage, reproductive challenges to psychological strain, these biological limitations cannot simply be engineered away. Creating truly self-sustaining habitats requires closing resource loops with near-perfect efficiency, while the legal and economic frameworks for space development remain underdeveloped and potentially problematic. This sobering assessment doesn't mean we should abandon our cosmic aspirations, but rather approach them with greater wisdom and patience. Perhaps the most valuable insight from studying space settlement scientifically is how it reveals the extraordinary interconnectedness of Earth's systems that support human life. As we contemplate reaching for the stars, we simultaneously gain a clearer understanding of what makes our home planet so precious and irreplaceable. The path to becoming a multi-planetary species may be longer and more challenging than popular narratives suggest, but addressing these fundamental challenges will not only advance our space capabilities but deepen our appreciation for the remarkable planetary systems that make human civilization possible.

About Author

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Kelly Weinersmith

Dr. Kelly Weinersmith is adjunct faculty Biosciences department at Rice University, where she studies parasites that manipulate the behavior of their hosts. She also cohosts Science…sort of, which is one of the top 20 natural science podcasts. Kelly spoke at Smithsonian magazine’s The Future Is Here Festival in 2015, and her work has been featured in The Atlantic, National Geographic, BBC World, Science, and Nature.

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