Craterhab Technology: Adapting Martian Habitat Systems to Combat Chronic Hypoxia in High-Altitude Mining in the Andes - A White Paper
- M Akbar Hussain
- Jun 3
- 30 min read
Dr. M. Akbar Hussain
M. Ayaz Hussain
M. Mehdi Hussain
Rida Fatima
Raúl Carretero
I. Abstract
The Andes is home to most of the world's highest altitude mines. A large number of these mines are located between the altitudes of 2,800m and 5,200m, where hundreds of thousands of people live and work for prolonged periods of time, pushing their physiology to the limit. While most of the people residing and working at these altitudes adapt to the thin and oxygen-poor atmosphere through increase in the oxygen carrying capacity of their blood, this comes at the cost of developing cardiovascular and respiratory disorders, causing long-term deterioration of their physical and cognitive abilities. This leads to fatigue, poor concentration, accidents, absenteeism, reduced productivity and a lower life expectancy. Traditional solutions, such as routinely rotating the workers to lower altitudes for recovery, present logistical and operational challenges. An alternative approach can involve creating pressurized enclosed environments at high-altitude mining sites to simulate lower-altitude atmospheric conditions.
Craterhab Technology is a patented large-scale pressurized inflatable habitat system concept developed by Mareekh Dynamics to turn small craters on Mars into mini-terraformed environments for permanent human settlement on the red planet. This technology also offers a promising terrestrial application. Scaled down versions of these pressurized habitat systems may offer a compelling solution to the terrestrial problem of altitude sickness among the miners working at high-altitude mining sites. These pressurized habitats can maintain an internal pressure well above the ambient low atmospheric pressures at high altitudes to simulate higher atmospheric pressures of lower altitudes, obviating the frequent need to rotate between high and low altitude locations. The large-scale deployment of Craterhab Technology in the highest-altitude regions of the Andes and Tibet will serve as a definitive proof of concept for habitat technologies at this scale. By leveraging the naturally low ambient atmospheric pressures at these altitudes, it enables real-world testing and refinement of the engineering parameters required for future Lunar and Martian applications.
Abbreviations
AIH = Acute Intermittent Hypoxia AIRS = Active Integrated Radiation Shield AMS = Acute Mountain Sickness CMS = Chronic Mountain Sickness H2M = Halfway to Mars HACE = High Altitude Cerebral Edema HALP = High-Altitude Low-Pressure HAPE = High Altitude Pulmonary Edema MOLA = Mars Orbital Laser Altimeter SMR = Standardized Mortality Ratio SPR = Standardized Prevalence Ratio
II. Introduction
Working at high-altitude mining sites in the Andes, often at elevations exceeding 2,500 meters above sea level, presents significant physiological and occupational challenges. The combination of hypobaric hypoxia, low ambient temperatures, and reduced atmospheric oxygen content imposes a continuous strain on the human body. Miners in these environments are required to perform physically demanding tasks while operating at significantly reduced oxygen saturations, frequently pushing their physiological limits. Prolonged exposure to such conditions can lead to chronic adaptations, including cardiopulmonary remodelling and hematological changes. While being compensatory, these changes may contribute to long-term health deterioration. Cognitive function may also be impaired, increasing the risk of occupational accidents and poor decision-making. Over time, these stressors are associated with a markedly reduced life expectancy and quality of life. Importantly, this burden is not limited to miners alone; millions of high-altitude residents including workers, researchers, and local populations face similar long-term health consequences associated with chronic hypoxia.
III. Demographic History of High-Altitude Regions
High-altitude regions, generally classified as areas above 2,500 meters (8,200 feet) such as Tibet, Himalayas, and Andes, have been inhabited by humans for over 8000 years (Lu 2024). While the human organism has emerged from the tropical climatic regions of the African Rift Valley, prolonged habitation at altitudes has given enough time for the residents of these regions to develop unique physiological adaptations to chronic hypoxia, including higher hemoglobin and red blood cell concentration, increased lung volumes, and more efficient oxygen utilization at the cellular level.
The demographic history of high-altitude regions has been shaped by migration, climatic fluctuations, and socio-political developments (Ehrlich 2021). In the modern era, high-altitude populations have been influenced by mining, tourism, and economic globalization. Mining and infrastructure development especially in the Andes region has seen massive growth in population over recent decades (Moraga 2014). This is a fairly short amount of time for any adaptation to develop for the high-altitude plateau environment with a thin and hypoxic atmosphere, leading to a vast majority of these populations to remain poorly adapted to live at these altitudes. Moreover, with the rapid boom in the mining sector for copper, aluminum and gold in the 20th century and with continuous expansion of the mining operations, hundreds of thousands of miners from lower altitudes such as those at sea-level are living and working at these high altitudes, and having to push their physiology to beyond the limits of human endurance.
At present, over 140 million people live above the altitude of 2,500m (Moore L.G. 2001). 15-25 percent of these populations suffer from chronic hypoxia and related complications, or are at risk of developing these (Zubieta 2024).
IV. Altitude Sickness; Acute vs Chronic Mountain Sickness
Acute Mountain Sickness (AMS) commonly affects unacclimatized individuals from near sea-level altitudes who ascend rapidly to elevations above 2,500m. It usually causes systemic symptoms related to low partial pressure of oxygen in the thin atmospheres of high-altitude regions, and includes nausea, vomiting, headaches, fatigue, poor appetite and insomnia. These symptoms usually resolve within 2 to 3 days with proper care, though it may take up to 40 days to fully acclimatize to higher altitudes (Zubieta 2007).
While most visitors at high altitudes acclimatize well after an initial increase in the quantity and oxygen carrying capacity of the red blood cells, a smaller fraction of individuals may suffer from more serious complications during the acclimatization phase. These include High Altitude Pulmonary Edema (HAPE) or High-Altitude Cerebral Edema (HACE) which can carry a mortality of up to 50% if untreated (Jensen 2023).
Living at high altitude permanently or for very long periods leads to an adaptation of the human body to function at optimal level through improving the body’s capability to absorb and carry the available low oxygen more efficiently. This includes certain changes in the body’s make-up such as increased lung volumes, increased blood pressure in the lungs, increased size of the right side of the heart, and increased number of red blood cells per circulating blood volume, also known as Polyerthrocythemia (Zubieta 2024). These changes are useful adaptations, but may not be ideal in many cases and become a trade-off in the form of slowing of the mental function, long-term lungs and vital organ damage, poor mental health and judgement, lack of sleep and shortened life-span. This spectrum of conditions is known as Chronic Mountain Sickness (CMS), or Monge’s disease (Villafuerte 2016) which is a direct consequence of chronic hypoxia. Incidence of Monge’s Disease per population number is related to the altitude, age, gender and existence of pre-morbid conditions or diseases. In El Alto at 4,100m altitude, over two thirds of men and one-fifth of women suffer from CMS which is statistically very significant (Zubieta 2024).
Perhaps the worst hit group by the permanent or long-term hypoxia are the miners working in mines above 3,500m altitude, with a huge number working above 4,500m and reaching heights of 5,100m such as the gold mining permanent settlement of La Rinconada. Barely any miner lives beyond fifty years of age in this town of roughly 30,000 individuals who call it home (Champignuelle 2024).
Mining industry in Andes has boomed in last few decades with opening of new mines at seemingly impossible altitudes for human endurance for any length of time, including few of the world’s largest mines located above 4,600m such as Antamina Mine in Peru, Collahuasi Mine in Chile and more recently opened Filo Del Sol mine in Argentina that is expected to exceed its mining operations above 5,000m (Fig. 2).
V. Current Measures
A. Acute Hypoxia
Prevention is always the best strategy. This involves slow and effective acclimatization such as ascending no more than 300-500 meters in a day (Sherpa, Hackett 2024). This gives the body enough time to adapt to the lower atmospheric pressures and oxygen levels of the higher altitudes. Another strategy, usually adopted by the mountaineers is to climb high to gain acclimatization and sleeping low – a few hundred meters lower than the attained altitude to recover from the acute hypoxia of the gained prior altitude, and improve acclimatization (Burtscher 2016).
Correcting hypoxia is the mainstay of the treatment of AMS. Mountaineers carry oxygen bottles when they ascend above 7,000m. Above 8,000 m, the partial pressure of oxygen is so low, it is usually termed as the Death Zone at the Eight-Thousander peaks, where human survival is not possible without supplemental oxygen unless for a short period and with an exceptional level of acclimatization (Szymczak 2021).
First-line therapy with 2-3 litres of oxygen per minute is a life saver and usually reverses many of the potentially fatal consequences of low oxygen. However, it is not a substitute for a rapid descent to lower altitudes, as leakage from the blood vessels leading to HAPE and HACE continues at lower atmospheric pressures of high-altitudes, despite improved oxygenation through supplementation. In many situations, rapid descent is not possible, such as mountaineers climbing the highest peaks, (where the base camp may still be much higher than the safe altitude), or being in a geographical location distant from the lower and safer altitudes such as in Tibet or Altiplano, or due to meteorological or operational constraints, such as a bad weather. In such situations, hyperbaric chambers (Simancas 2018) or much smaller Gamow bags (Taber 1990) may be helpful where higher pressure simulating a safer lower altitude is created which can save lives. Larger hyperbaric chambers are very costly and heavy, and are usually reserved for specialized purposes. Smaller Gamow bags are more portable and cost-effective. Both these options have a limited scope and are mainly for a single person emergency use. They are small and claustrophobic, and have limited options for intervention or emergency procedures when pressurized.
Other adjuncts include more conservative means such as increasing the fluid hydration, chewing coca leaves which stimulates breathing and increases alertness, or therapeutic treatments such as diamox (acetazolamide); a diuretic which also increases the depth and rate of breathing, and improves oxygenation.
B. Chronic Hypoxia
Many mines in Chile located above 4,500m such as Collahuasi Mine with over 5,000 workers (collahuasi.cl) are required to send their workers to the accommodation facility at 3,850m altitude to sleep and rest for a few hours in each 24 hrs daily cycle. Once every month or so, they also send the miners to much lower altitudes to their home towns near the sea for many days at a time. (Richalet 2002). The idea of these rotational shifts is to convert the Chronic Hypoxia situation into an Intermittent Hypoxia. Rotational shifts over several days and weeks achieve a Chronic Intermittent Hypoxia whereas daily rotation to lower altitudes achieves Acute or Short-Term Intermittent hypoxia.
Studies in the flight crew, who alternate between sea-level pressure of 1.0 bar and the cabin pressure of 0.75 bar (corresponding to 2,500m altitude) at a cruising altitude of above 12,000m, up to several times a day, show the same overall health outcome as people living at sea level altitude (Vela 2022). On the other hand, periodic rotation between high and low altitude once every few days also helps resolve the chronic hypoxic damage without losing the acclimatization. Although it helps reverse many effects of hypoxia, periodic rotation is less effective in achieving an optimal outcome than the Acute Intermittent Hypoxia achieved through daily rotations.
Rotational shifts have their own limitations and are not always possible for all the high-altitude mines. This is due to the cost, loss of working days, some loss of acclimatization, and also the geographical distances and logistical challenges of travelling between high-altitude mining sites and lower altitude towns of residence. While more of a possibility in Chile due to its proximity to the sea, it is not feasible for the highest altitude mines in Peru, Bolivia and Argentina. But it is indeed considered as one of the most effective current measures to counter the long-term damaging effects of chronic hypoxia.
VI. Craterhab Technology - A Potential Solution from Space for Altitude Hypoxia
Learning to live and survive in the low-pressure environments is vital for the progress of humans in the modern space age. Space and planetary environments represent the ultimate frontier for testing the limits of human imagination and our resolve to explore the unknown and discover new horizons. Visiting the planetary environments with little to no atmosphere such as Mars and the Moon for a short period of time is one thing, where one can live for a few days or even a week or so in the confines of a space suit or a space-craft, or inside a pod-like habitat with the minimum volume of space barely enough for survivability and handling of experiments etc. But a long-term permanent settlement on Mars or the Moon is an altogether different challenge, which will require much larger volumes of pressurized spaces where humans can come out of the confines of the space suits and live in a spacious habitat with as close to an Earth-like environment as possible, and freedom to roam around.
Mars is the humanity’s next giant leap. It is distant and cold, has lower gravity, and a far lower atmospheric pressure as compared to Earth. With a tilt of nearly 25 degrees and having seasons, a little over 24 hours day with regular sunrise and sunsets, and having plenty of water in the form of polar ice caps and subsurface ice, it is also the closest thing to Earth in the entire Solar System from a human habitability perspective. In addition to the logistics and cost involved in getting there, there are several factors on Mars that will limit our ability to settle there – the most critical one is perhaps the low atmospheric pressure on the red planet, standing at an average of 0.006 bar, or less than 1% that on Earth. Every habitation technology conceivable for Mars revolves around the need to maintain an adequate Earth-like pressurized internal environment against the near vacuum of the Martian atmosphere.
Mars is not only distant, but the window of opportunity to travel to Mars only opens once every 26 months. Lag in the communication between Earth and Mars ranges anywhere between 7 minutes and 45 minutes. Humans have to live fairly independently on Mars and this requires numbers. For settling on Mars, a minimum threshold of a number of humans is needed with skills in many overlapping trades for contingency. The number may run in several tens to over a hundred even during the early ground-work for a permanent settlement on the red planet. This will require large habitable spaces on Mars for housing, manufacturing (e.g., 3D printers and workshops), food production, research labs, and storage. Multiple interconnected habitats may be needed for contingency and safety. Many current designs with rigid structures may be prohibitively expensive to build on Mars in meagre resources available on the red planet.
VII. Engineering Overview
Craterhab (US patent no US D985798 S and US 2022/0290422 A1) is an inflatable pressurized dome concept made of ultra-strong composite fabric, designed to contain at least 1 bar pressure with a safety factor of 2.5. On Mars, the desired pressure inside the habitats may be less than 1 bar to minimize structural load on the habitat, and optimization of the use of precious oxygen while achieving an adequate breathing environment. These hemi-ellipsoid domes are designed to be anywhere between 50m and 500m in diameter, and tethered to underground anchors holding them in place under immense inflation pressures.
Craterhab concept revolves around the idea of achieving the largest volume-to-material ratio, durability, ease of transport and construction, while carrying a strong terrestrial application – all within the realm of the existing technology.
The name Craterhab is a short form of Crater Habitat. Craters on Mars offer several advantages over level ground as a choice for building habitats.
A. Compactness
Martian gravity is 38% that of Earth. This also means the soil on Mars is comparably less compact. Lack of exposure to the cementing process by water for billions of years has also contributed to its relatively less compactness. Martian surface is covered in a layer of loose regolith with a density of 1.5g/cm3 (Carlton), which is 5-6 m deep on average in most regions of Mars (Warner 2016). This makes most of the Martian surface unsuitable for anchoring and securing large pressurized inflatable structures to the ground. But Mars offers a unique geological opportunity which may solve this issue. And that is the presence of impact craters.
There are over 635,000 craters on Mars which are larger than 1 km in diameter, and those over 50 meters are potentially exceed 10 million in number, based on the data from NASA and the Mars Orbiter Laser Altimeter (MOLA). High-resolution imagery from orbiters like HiRISE and CTX continues to identify more small craters. With the exception of a few craters of volcanic origin, nearly all of these craters were formed by meteorite impacts due to the thinner atmosphere on Mars and got preserved due to the lack of surface erosion. When an impactor strikes a planetary surface, it gets obliterated and leaves an excavated feature or crater on the impacted surface due to its kinetic energy and the shock wave thus generated at the impact. The shock wave of the impact pushes material in all directions, including the material thrown upwards and outward forming an ejecta blanket. The material that is pushed to the sides and below during the impact crushes against the land surface matter forming the crater walls and the floor, which is much more compact than the regolith covering the surrounding surface. The impact process also exposes the firmer solid ground beneath the layer of regolith. Over time, loose material accumulates in the crater floor burying much of the compacted surface. The crater rim however remains intact and exposed which is mainly composed of a hardened rock called impact breccia formed as a result of the heat, compression, and shock of the impact. Impact breccia is denser and more compact with less porosity than the surrounding regolith – with a bulk density of 2.5g/cm3 and a grain density of 3g/cm3 or above, as per the data of the breccias in the return samples from the Moon (Kiefer 2015). This makes the crater rim an excellent interface to attach the Craterhabs dome to the concrete pile anchors or spiral anchors embedded in the bedrock beneath the surface and secure the inflated dome.
B. Depth
On Mars, there are two extremely precious assets; the building material, and the habitable volume. Many surface city design concepts of Mars depict small rigid pod-like structures, with some as small as a bus and some as large as a tennis court, all interconnected through surface and sub-surface tunnel systems. These not only offer a very small total habitable volume for a base or a city, the total amount of material used to build these structures is also humongous. For a distant world like Mars, this model may not be entirely affordable to create large-scale habitat solutions for a long term or permanent human settlement on the red planet.
Martian Craters offer a naturally excavated volume which can be utilized by turning these into habitable mini-terraformed environments. This can be done through building a roof above the crater with its periphery embedded in the crater wall. This will offer a great volume-to-material ratio, which means achieving the greatest amount of volume for the least amount of material used; a perfect solution for a resource constrained environment of Mars. The inner slopes of a crater offer another advantage; providing an angled interface between the surface and the subsurface, and will facilitate the construction of the underground back-up habitats and tunnel systems.
C. Partial radiation protection
Martian surface receives hundreds of times more radiation than the surface of Earth. Earth’s atmosphere offers protection against Solar radiation (Ultraviolet rays and Solar wind) while Earth’s vast magnetic field protects against the Galactic Cosmic Radiation (GCR) composed of Alpha particles from distant supernovae and other high-energy cosmic phenomena. Over 90% of the radiation reaching the Martian surface is GCR which consists of very high energy 0.1 to 1.0 GeV Alpha radiation and is a bigger concern from the total radiation dose perspective than the UV and Solar wind combined (Hassler 2013). Mars has no magnetic field to deflect or reduce the solar or cosmic radiation, neither does the thin Martian atmosphere offer any protection. The planetary body of Mars would naturally stop 50% of the total radiation coming from the planetary side of the cosmos. Living inside a Crater will drop this exposure further down to nearly one-third. For human survival, though this is still not enough protection, lesser power will be required to generate the Active Integrated Radiation Shield (AIRS) built in the habitation dome structure. AIRS is our patented on-demand powered radiation shield, details of which are beyond the scope of this discussion.
D. Circular shape
In addition to the compactness and the volume craters have to offer, the near-perfect circular shape of these craters may also come in handy for the ease of engineering, calculations and predictability of the behaviour of pressurized habitat systems.
VIII. The Design of the Craterhab
Craterhabs are multilayered inflatable fabric domes of very high tensile-strength composite material. The gross structure is a hexagonal dual-cable skeletal framework of Spectra (or Dyneema) cables forming a hemi-ellipsoidal dome structure. At the periphery, the skeletal frame extends into the compact crater rim through a concrete sandwich wall and integrates with a Dyneema tether system. This system continues through an inflatable Dyneema or Kevlar torus anchor located just beneath the sandwich wall, providing both a sealing interface and cushioning to absorb the tether system’s tension. The tether system continues below to attach to a subsurface concrete pile radicular anchor system (or helical metal anchors for smaller domes). The anchors will be embedded deep into the crustal bedrock beneath the crater rim. This configuration continues along the entire periphery of the crater rim.
The main body of the Craterhab dome consists of individual hexagonal Kevlar-resin-carbon fiber composite panels, each wrapped around the Dyneema skeletal cable frame like trampolines, effectively filling in the hexagonal segments. The material for the Craterhab construction is carefully chosen (Vogler 2002) for their superior strength, durability and minimal stretchability to maintain the desired pressure, and restrict belching between the apertures of the hexagonal skeletal frame when inflated. The inner and the outer surfaces of these Kevlar-composite layers are covered by thicker Silicone-Polyethylene composite hexagonal segments which give sealing property as well as maintain translucency (for natural ambience) and offer an excellent UV protection. The outer layers are also covered in a thin layer of Kapton to protect the silicon-composite layers from the dry near-vacuum atmosphere of the planet Mars. The advantage of using a high-tensile composite fabric material in the construction of the dome is to give a natural forgiveness for the differential stresses over very large structures such as a Craterhab which can be up to 500m in diameter.
Though Mars has a very thin atmosphere with gentle breezes barely enough to move a long grass-blade (if there were any on Mars!), the global dust storms that ravage the Martian surface once every few years and last for months, can pack a powerful punch on the structure of a Craterhab due to its very large cross-sectional area of tens of thousands of square meters. To reduce the wind-loading, the large Craterhabs will not be hemispherical, but rather hemi-ellipsoidal or lens shaped. To reduce the wind stress and maintain the integrity of the dome during the dust-storms, the dome will be internally secured through a bi-radial internal cable system connected to the dome ceiling at one end and to the underground anchors at the other end.
The Dyneema hexagonal skeletal frame of the dome is the main stress-bearing part of the body of the Craterhab, absorbing and withstanding the hoop-stress as a result of the inflation pressure of 0.6 bar with load bearing safety factor of at least 2.5x (or 1.5 bar internal pressure). The peripheral tether system connected to the underground anchor system will bear the vertical vector of the inflation force tending to lift the structure upwards, and the bi-radial internal cable system is designed to uniformly distribute the load and help improve the wind loading of the entire dome structure. Here is a table of the calculated diameter (D) of the Dyneema skeletal frame cables, as per the diameter of the dome and is calculated for 1.5 bar inflation pressure.
IX. Core Concept for Mars
Mars has an atmosphere which is very tenuous, with an average pressure of 0.006 bar (ranging from maximum 0.012 bar at the lowest point on the Martian surface, the Hellas Planitia, to the minimum 0.0015 bar at the top of Olympus Mons which is the highest point on its surface). To give it a perspective, this pressure is equal to the atmospheric pressure on Earth at an altitude of about 32km, which is even above the altitude of highest-flying aircrafts, or essentially near-vacuum and should be treated as such in all the calculations of the habitat pressures and its background engineering.
The purpose of any habitat system on Mars is to create an Earth-like atmosphere contained within the habitat system. Ideally it should be 1 bar, which will translate as a 10 tons of outward inflation force per square meter of the habitat structure. But what is the limit of lower atmospheric pressure which is the bare minimum for human sustenance on a long-term basis? Can the highest permanent settlement on Earth, La Rinconada at 5,100 m altitude with an atmospheric pressure of roughly 0.52 bar serve as a reference? Perhaps not. Coming down to the much larger city of El Alto in Bolivia of nearly one million inhabitants at 4,100 m with an atmospheric pressure of 0.6 bar, the population has closer to normal life span and the quality of life in healthy individuals, through a lifelong acclimatization in the majority of inhabitants. The advantage of maintaining 0.6 bar pressure inside the pressurized habitat system on Mars is the reduction in the inflation stress on the habitat structure, so lesser material is required to meet the optimal strength and resilience, while maintaining optimal health and quality of life of the inhabitants.
The Craterhab concept, using inflatable fabric domes, aims to achieve this while extending its utility to offer low-cost and easily constructed habitat systems. By leveraging the inherent advantages of Martian craters, it enables the creation of large, mini-terraformed pressurized environments within the craters, ranging from 50 to 500 meters in diameter, and interconnected through surface and subsurface tunnel network. The mini-terraformed crater habitats will feature residential areas, manufacturing units, businesses and amenities, food production zones, and entertainment spaces, thus creating an Earth-like environment and minimizing the need to go outside in a spacesuit or pressurized rover.
Even during the initial stages of establishing a permanent human presence on Mars with a few tens of individuals including astronauts, engineers, geologists, medics, and researchers, larger volumes of space bigger than the cramped volumes of landers will be needed. Inflatable fabric habitats will provide a practical solution. The entire inflatable habitat, providing several hundred cubic meters of habitable volumes can be packed and hauled from Earth and deployed on the Martian surface. Different small habitat ideas have been discussed in the literature and a few have recently been tried; the most notable ones are the Bigelow Expandable Activity Module (BEAM), Lockheed Martin’s Deployable habitat and NASA’s Transhab concepts and models (Kacha 2024). While these habitats provide sustainability for short-term and mission-oriented stay for a very limited number of people on the red planet, they do not provide the necessary ingredients for a long-term permanent and generational settlement of a large number of humans on Mars which requires a much larger, Earth-like internal environment with necessary elements for sustenance, comfort, privacy, and for the physical and mental wellbeing.
In the Martian context, the utility of a habitat system at the scale of the Craterhab comes after the establishment of a long-term small-scale base. The main aim is to provide a mini-terraformed environment with provision to live a life as close to the one on Earth. Therefore, the design of a Craterhab is fundamentally different from the above-mentioned small inflatable habitats. A complete Craterhab system cannot be carried in a pre-fabricated form in a space-ship. For smaller Craterhabs (50m or so in diameter), the above-ground dome section can still be folded into a very small volume and carried in a prefabricated form, but the larger domes (100-500m diameter) can only be transported in segments and then assembled on Mars. The underground section of the Craterhab including the sandwich-wall, torus anchor and the subsurface anchors must be constructed or assembled on Mars using local and imported resources, for all Craterhab sizes.
The surface and underground sections of a Craterhab can be built through a Robotic Radial Modular Assembly using a mobile, lightweight pivot or jib crane deployed in the centre of the crater. Such cranes can be specifically designed for Mars and can be very lightweight, folded into smaller volumes for transport and open up when deployed. Such cranes can not only carve a narrow circular trench in the crater rim, build sandwich walls along the inside of the trench to secure it, and lay bore-and-pour concrete piles or install helical anchors, they can also weave the Dyneema skeletal frame and install hexagonal Kevlar-composite and silicone-polyethylene sheets within the skeletal frame – controlled remotely from the surface base on Mars, Martian orbital station, or even from Earth (factoring in the communication lag).
X. Terrestrial Utility of the Craterhab Concept
Many of the technologies developed for space applications find their utility in solving Earth-based problems. Their applications range from communications, miniaturization of technology, recycling, clean energy generation, healthcare and in material research. Craterhab Technology is no exception. The ability of the Craterhab concept to create pressurized environments against low ambient pressures got our attention to the high-altitude regions of the world with sizable populations at risk of developing short- and long-term complications of the thin atmosphere low in oxygen at those altitudes.
XI. Core Concept for Earth
Scaled down versions of the Craterhab, something in range of 20-50m in diameter and ability to hold up to +0.2 bar internal pressure above the ambient outside pressure can be constructed in high-altitude low-pressure (HALP) environments on Earth to solve the short- and long-term altitude sickness problem.
Hundreds of millions of people permanently live and work above altitudes of 2,500m. People working in the high-altitude mining industry are particularly vulnerable to the altitude hypoxia and its complications. Hundreds of thousands of miners and workers stationed at mines between 4,000 to 5,000 meters above sea level mainly in the Andes but also in Tibet, Central Asia and Indonesia, push their abilities to the limit at altitudes which are not suitable for any length of stay from a human health and endurance perspective.
Craterhabs built at altitudes above 3,500m can simulate lower altitudes of 2,000 to 2,500m by holding pressures around 0.75 bar in environments with ambient pressures of 0.5 to 0.6 bar (0.15-0.25 bar above the ambient pressure). 0.75 bar pressure corresponds to around 2,500m altitude which is usually considered a lower threshold for developing acute or chronic altitude sickness (Prince 2023). To mitigate the altitude hypoxia and its complications, miners working at high-altitudes with hypoxic environments can spend 8-10 hours every day inside these pressurized domes simulating lower altitudes without actually travelling down to those altitudes. Inside the pressurized domes, they can recover from the hypoxic effects on their body tissues on a daily basis. This is a similar situation to which the airline crews are subjected to when they ascend from sea-level pressures to cabin pressure of 0.75 bar during the cruise phase of the flight, sometimes up to few times in a day, enduring a pressure difference of 0.25 bars within short intervals. As mentioned previously, their bodies are subjected to Short-term Acute Intermittent Hypoxia (AIH). Studies show that the Standardized Mortality Ratio (SMR) and Standardized Prevalence Ratio (SPR) of people subject to the AIH is the same as people living at sea level (Vela 2020).
In other words, much of the negative health effects of chronic hypoxia in individuals living and working at high altitude can be resolved if it is turned into a short-term Acute Intermittent Hypoxia (AIH). And this is what we aim to achieve using Craterhab Technology at high-altitude mining sites (Fig. 5). Miners are subject to chronic hypoxia at high altitude. Rotational shifts to lower altitudes can at best achieve long-term Chronic Intermittent Hypoxia (CIH) but this does not quite match the improvement that comes with achieving a short-term Acute Intermittent Hypoxia.
Here it should be noted that through the use of Craterhabs at high altitude, we are not trying to achieve a sea-level pressure of 1 bar inside these habitats. The reason for this is to avoid the loss of acclimatization and also avoid the hypoxic shock the human body may become subjected to during egress from the pressurized habitat. Use of mid-level altitude pressures equivalent to the altitudes of 2,000-2,500m and not exceeding a pressure difference of +0.25 bar between inside of the habitat and the outside pressure is essential to maintain the acclimatization needed for the outside work in hypoxic environments with atmospheric pressures as low as 0.5 bar.
Use of large pressurized habitat systems such as Craterhabs achieving AIH in a chronic hypoxic environment of high-altitude mines will improve the quality of life and productivity of hundreds of thousands of miners working at those altitudes, and save lives. It can also reduce the revenue loss of the mining industry as a result of altitude sickness among the miners (Fig. 6).
Some of the modifications that may be required to adapt the habitat designed originally for Mars to apply on Earth include;
Reduction in size: For terrestrial application of the technology, mini-terraforming and open interior spaces will not be needed, as they are not intended for a permanent stay. Each Craterhab can be designed to accommodate 20-50 people at a time, depending upon the need of treating AMS, preventing CMS, or facilitating tourism. 20-50m diameter Craterhabs may be sufficient for this purpose.
Lower pressure gradient: A pressure gradient of +0.15 bar to +0.25 bar between interior and exterior pressures will be enough to simulate atmospheric pressure of lower altitudes on Earth (~2,500m) at mining sites above 3,500 meters, which is much lower than maintaining +0.6 bar pressure inside the habitats required on Mars.
Reduced translucency: Since the domes will primarily serve as sleeping quarters for miners, opacity may be preferable over the translucency used in Martian Craterhabs, where admitting natural sunlight is essential for plant growth and maintaining diurnal rhythms. This will simplify the construction and obviate the need for translucent Kevlar-composites, thus allowing the use of simpler and cheaper fabric.
Lack of radiation shield: Earth’s magnetic field and the thick atmosphere prevents almost all of the Solar and Galactic Cosmic Radiation (GCR). So, there is no need for a radiation shield in the Craterhabs designed for Earth.
All these changes will help scale down the technology and make it cheaper and simpler to construct on Earth.
XII. High Altitude Habitat Testing and Astronaut Training
Application of the Craterhab Technology to combat hypoxia at the highest altitude mines has one very interesting application – establishing training bases for astronauts destined for Mars.
The optimal pressures maintained inside Mars habitats will be around 0.6 bar, against a near-vacuum outside. Regions higher than 5,000m in altitude in Andes and Tibet have an atmospheric pressure of around 0.5 bar. There are plateaus in these regions which even exceed 5,400m in altitude. These conditions are best suited for training bases for Mars for their low pressures and temperatures, and remoteness.
At lower altitudes such as sea level, any Mars simulation habitat being optimized and tested for holding a 0.6 bar pressure above the ambient outside pressure will have to contain nearly 1.6 bar (pressure at sea level being 1 bar). While the material and engineering testing can be performed with these habitats (though sub-optimally), training of astronauts inside these habitats will not be suitable, not only due to the physiological strains of the hyperbaric exposure, but also due to further de-acclimatization of their bodies for a true Martian habitat on the red planet with a pressure of 0.6 bar. It is important to build and test these habitats in lower pressure conditions with rapid change in temperatures and exposure to very low temperatures, such as high plateaus in Andes and Tibet. It is also important to train astronauts destined for Mars (“Marstronauts”) in remote locations with low resources, where they can perform outside excursions only in pressurized suits to train themselves physically and mentally for a life on Mars.
XIII. Halfway to Mars (H2M)
Halfway-to-Mars (H2M) (Fig. 7) is a conceptual framework that envisions the use of pressurized habitat technologies to bridge the gap between terrestrial applications and the Martian colonization. The idea behind H2M is that high-altitude, low-pressure environments on Earth (such as the Andes, Himalayas, and Tibetan Plateau) serve as test-beds for technologies that will be essential for human survival on Mars.
Many high-altitude mining sites are close to plateaus over 5,000m in altitude. Craterhab domes can be constructed at such plateaus using the engineering infrastructure of the participating mines where domes with pressures of 0.8 bar to 1 bar can be maintained, against an external pressure of 0.5 bar (+0.3 to +0.5bar). Astronauts living in these domes will be subjected to mild hypobaria to normal pressures while testing the dome material and design subjected to positive pressures relative to the outside atmospheric pressure.
Astronauts can be trained in three phases;
● Phase 1 can include living inside a 1 bar habitat (+0.5 bar above the environmental pressure). Any excursion outside will subject the human body to a sudden 0.5 bar pressure drop which can be extremely uncomfortable and outright dangerous. So, it must be done using a pressurized suit and pressurized rovers, in exactly the same way it will be done on Mars. These domes will best suit the material, design and structural testing of the Craterhab habitat system (including life-support equipment and airlocks)
● Phase 2 can include living inside 0.8 bar habitats (+0.3 bar above the outside pressure). These domes will be suited for gradual transition from sea level pressure inside the domes to slightly hypoxic atmospheres to achieve acclimatization.
● Phase 3 can include living inside 0.6 bar habitats (+0.1 bar above the environmental pressure). These domes are not optimized for structural testing but will be best suited for the level of acclimatization required to live and function in low pressures maintained inside the habitation volumes of the space-craft enroute to Mars and inside the Martian habitats maintained at 0.6 bar. This facility will be the final training phase before sending humans on a several months-long journey to Mars and a long-term stay (months to years) on the red planet.
The process of acclimatization can either start during the 6-9 months transit to Mars inside the spaceship maintaining a 0.6 bar pressure (which may drop down to 3-4 months with improved propulsion technologies), or it can be done at Earth, months before the journey to Mars begins. The advantages of pre-acclimatization before the space travel are two-fold:
1. A space-craft to Mars will be a place with extremely limited resources, which can be further compromised by crew sickness or their sub-optimal function. Maintaining an optimal physical and mental function of the crew at a cabin pressure equal to the prospected Mars habitat pressure (0.6 bar) may require up to 6 weeks of acclimatization (Zubieta 2007). Conducting this on board, while carrying a risk of developing AMS, HACE and HAPE, especially in the first few days of the journey can compromise the whole mission. Acclimatization on Earth at high altitude Mars training bases will help train the crew for the low cabin pressure during the long journey to Mars.
2. Several high-altitude mines in South America are above 4,500m altitude and are in close proximity to plateau environments of 5,000m or above. These are some of the remotest and harshest places on Earth, especially those in the Atacama Desert which are also the driest and are sterile. With a barometric pressure approaching 0.5 bar or lower, no other place on Earth comes close to these locations in mimicking the harsh Martian environment (except for the Dry Valleys of Antarctica). Using the proximity of these locations to the established mining sites while maintaining a sense of remoteness and living in mock Mars bases inside pressurized domes slightly above the ambient pressure, will deliver an unmatched training and experience of living on Mars. These training bases will also help develop safety protocols for establishing and maintaining a permanent human presence on Mars.
XIV. Conclusion
A large-scale inflatable dome habitat system such as the Craterhab concept presents a viable, practical and cost-effective solution that bridges space exploration and terrestrial applications, addressing the critical challenge of chronic hypoxia in high-altitude mining while advancing the development of large-scale pressurized habitat systems for Mars. These pressurized habitats have the potential of transforming the way workers live and recover in extreme environments, reducing health risks, improving productivity, and achieving life and career longevity. At the same time, their design principles align with the future needs of Martian colonization, providing a viable framework for establishing spacious, pressurized environments on the red planet. The Halfway-to-Mars concept further strengthens this dual-purpose approach, allowing for real-world testing of Mars habitat systems in Earth's high-altitude, low-pressure environments while serving as a training ground for future astronauts. These dual-use pressurized habitats can offer a pioneering step toward safer high-altitude living on Earth and sustainable human presence beyond our planet.
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