Anthropocentric Habitation of Mars Through Parametric Design
Logan Miller /// December 07, 2022 /// Portfolio Vol. 2
Mars has been a central subject of the space exploration discussion for decades. The Red Planet is an atypical destination, offering humanity a location to study the rudimentary stages of microbial life, as well as implement a greater understanding of how the evolution of the planet's surface can influence the future of our civilization. Conditions on Mars are severe, yet livable. The proposed mission ARES (Architectural Research Expedition of Space) seeks to capitalize on the habitable aspects that the planet offers and develop a sustainable solution regarding humanity's first manned mission to Mars. Comprised of autonomous and human-centered operations, ARES is a thirteen-year expedition with the intent of establishing and constructing a permanent, self-sustaining colony.
A system of three interconnected phases enables ARES to accommodate an initial crew of seven after the proposed site, Valles Marineris, has been readily prepared. Innovation in the 3D printing processes will provide a higher standard of living that limits the effects of radiation while establishing a suite of necessary amenities. This, in conjunction with several preconstructed temporary habitats and greenhouses, provides a system through which Martian crews can conduct a plethora of scientific studies while maintaining a healthy psychological and physiological state. The projected outcome of the mission will see an environmentally protected Martian colony that is prone to expansion and additional crewed missions to Mars.
1. Site selection
The process of evaluating and determining a location that will actively contribute to the success of a mission is paramount. Aspects such as average temperature, accessibility of sunlight and water, the probability and severity of dust storms, and regional scientific interest all contribute to the overall grade of a site. After considering these factors, Valles Marineris, the largest canyon in the solar system, has been identified as an ideal landing site and exploration zone for the ARES missions due to the following reasons:
1) Elevated likelihood of water: The discovery of unusually high levels of hydrogen in the center of Valles Marineris by the ESA-Roscosmos ExoMars Trace Gas Orbiter (2021) has led to the theorized existence of water, water ice permafrost, and/or large quantities of highly hydrated minerals buried in the ground of the canyon. This is of great significance for the scientific exploration of Mars and it may provide essential information about the planet’s history and evolution, as well as its potential for sustaining life.
2) Sufficient Earth-like lighting conditions: The canyon’s location along the Martian equator provides ample amounts of sunlight for astronauts, a necessary standard of living to achieve psychological well-being during a seven-year mission. Architecture has historically provided adequate lighting in dwellings to give occupants physiological and psychological comfort. In space architecture, the significance of lighting is more critical due to the lack of engagement with the exterior environment. The addition of a cupola on the ISS has given astronauts a feeling of joy and operates as a cradle, a retreat. Moreover, visually observing Earth, a scene that is familiar, combats the feeling of isolation and homesickness.
3) Radiation protection: The Martian atmosphere provides various thresholds in terms of shielding the surface from Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE), depending on the elevation level. Valles Marineris capitalizes on the few benefits that a thin atmosphere can provide. As an example, the average surface pressure of the planet is 0.6 kPa, while the pressure in Valles Marineris is over 1.2 kPa. Furthermore, Valles Marineris’ extreme canyon floor depth of seven km creates deep shadows and caverns, which provide additional radiation shielding. Hydrated regolith present in Valles Marineris also has the capability to provide additional levels of protection.
Greater insight to the site selection process can be found in the Mars Locations Research File.
2. M.A.R.S and Transit (ARES I)
ARES I Mission Perspective
The ARES I mission revolves around the Marshan Ascent and Return Shuttle (MARS) that is equipped with nuclear reactors, deployable robotic systems for 3D printing, preliminary supplies, and prefabricated greenhouses to the selected site. The primary function of ARES I is to test the safety of the entry and descent (EDL) of MARS before the first manned mission in 2035.
ARES I, and subsequent missions, will follow a powered Hohmann transfer trajectory from Earth to Mars. Final assembly and check out will be done at Lagrange Point 1 (L1), situated between Earth and its Moon, allowing for a safe installation and testing process of the nuclear reactors. The interplanetary transit will be performed using Nuclear Electric Propulsion (NEP). NEP consists of eight NASA Evolutionary Xenon Thrusters (NEXT-C), a model previously utilized on the Double Asteroid Redirection Test (DART). The performance of eight thrusters working in parallel will produce about 1.9 Newtons of thrust, with a specific impulse of 4,190 seconds. A metric that is sufficient to provide the required total impulse in approximately twenty-five days. The ion thruster, NEP, will only be used for interplanetary transit; methane-powered chemical rocket engines will be used to establish a highly elliptical orbit.
The hybrid propulsion method was deemed necessary due to the need to have the thrust for both descent and ascent to and from the Martian surface. Thereby, a chemical rocket engine with an equivalent thrust to weight ratio, as well as the need to reduce fuel mass for the interplanetary cruise, required a highly efficient drive system. The chemical propulsion engines were elected as the best option because of their ascent capability from the surface. Four SpaceX Raptor engines provide the necessary propulsion to launch the required wet lift mass of the ARES vessel; that being a 4.8 thrust-to-weight ratio at lift off from the Martian surface. In addition, the chemical engines will be necessary to avoid the tendency of “spiraling” in and out of Earth and Martian gravity wells, allowing for the NEP to take over at higher orbits. Overall, the chemical propulsion will be responsible for 4 km/s of Δv.
The NEP system takes advantage of the need to have a reliable power source once on Mars; the reactors for this system will be reused as surface power. In transit, the highly efficient gridded ion thrusters provide the remaining 6 km/s of Δv required to make the trip from Earth to Mars. The use here of NEP is not to shorten the transit duration, but rather to reduce the total fuel up-mass of the rocket. The required fuel mass when using the ion thrusters is approximately 1/3 the amount that would be needed for an exclusively chemical rocket. This is what enables a landed payload of 137 metric tons in a single vehicle.
For ARES I, the primary payload is the materials required for constructing the habitat and greenhouse, including 3D printing equipment, prefabricated greenhouse components, and power distribution instruments.
Entry and Descent Diagram
Chemical rocket engines will fire to start the entry phase from the parking orbit. Once the ARES rocket approaches the Martian atmosphere, all deployable radiator panels and solar panels will be retracted, allowing for a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) to be deployed and inflated. Thereby protecting the vehicle during its initial entry into the atmosphere.
Once the vehicle has slowed from hypersonic speeds, the HIAD is deflated and retracted back into the spacecraft. Simultaneously, three supersonic parachutes are deployed to slow the rocket and stabilize its trajectory. The primary descent and landing are handled by the four chemical rocket engines, burning from the retraction of the HIAD to touchdown on the surface. From the start of descent to touchdown, approximately 300 metric tons of fuel will be used. The combination of a powered landing and stabilization through a parachute provides a landing accuracy within one hundred meters of the desired site.
Temporary Habitat Section
After ARES I lands, secondary solar panels will open to provide power and allow pre-positioned rovers to move the reactors off of the spacecraft towards the reactor farm. The reactor farm is designed to provide power for the initial base construction phase and 3D-printing. The M.A.R.S. rocket will be used as a temporary habitat until a permanent 3D-printed structure can be erected.
The temporary habitat consists of inflatable modules, akin to NASA’s TransHab project. The system will be decompressed and packed within the ARES I MARS vessel. Upon arrival, the system will be inflated and promptly linked to airlocks aboard the ARES I rocket and future permanent habitat domes. The interior will be equipped with personal crew quarters and essential amenities including hygiene, dining, living, exercise, medical, and scientific laboratories, to ensure a higher quality of living.
The temporary habitat will present the crew with interior pressure conditions comparable to that on Earth, five to ten tons per meter squared (50 to 100 kPa). Following the inflatable portion of establishing the temporary habitat, a thick layer of Martian regolith will be spread across the surface of the structure to provide additional radiation shielding. Martian regolith has a density of approximately 1,500 kg/m3, equivalent to 523 kg of soil pressure per square meter. As a result, the inflatable habitat can support up to 19 meters of Martian regolith. Supplementary research has revealed that a meter of regolith can provide adequate shielding against both SPE and GCR. Once deployed, the robotic arm equipped on the ARES I rocket will begin to 3D print a 1.5-meter regolith shield over the temporary habit. The crew will continue to live in the ARES MARS vessel during this time period of two to four weeks. Once constructed, the crew will expand their base of operations by over two hundred percent in total area. The temporary habitat will serve as the crew’s home for over six months, as the permanent habitats will continue to be constructed during this period.
The ground systems for the habitat will initially consist of communications and 3D printing apparatuses. Once occupied, the habitat will be supporting a crew of seven, similar in size to the current International Space Station, which requires 76 kW in normal operation. The operation of the 3D printing technology by itself can be assumed to require less than the life support systems. This power will be provided by the eight nuclear reactors aboard ARES I. The selected reactors for the ARES vehicle, and subsequently for power production on the surface, is the Kilopower Reactor Using Stirling technology (KRUSTY), which will provide 10 kW of electrical power per unit.
Prior to the crew occupying the base of operations, reactors will need to be transported to a remote site for safety protocol. These reactors will ultimately be added onto by the set of reactors carried on-board the ARES II flight. This will eventually provide a full 80 kW of power for surface operations. The reactors will be deployed a minimum of 500 meters away from the habitat location, with a distribution box deployed to connect the reactors to a grid. This is an essential step that generates the ability to transmit power back to the base of operations along a 500-meter cable. This cable will be put in position by a rover on its return trip to the base.
Further study is required to determine whether the reactors can be operated at the base while it is uncrewed, or if the relocation must happen remotely before crew occupation. Supplies from ARES I will consist of materials and equipment for habitat construction; as a preceding mission, no food will be on board apart from one year's worth of emergency rations for a crew of seven (shelf stable rations similar to survival food on Earth). All cargo volume and mass not consumed by the construction equipment and additional materials will be used for spare parts as well as additional spares for the life critical equipment on board Ares I.
3. 3D-Printing a habitat
Kuja Preliminary Habitat Design Drawing
Surviving sustained radiation exposure is the primary roadblock when pioneering life on Mars. NASA implements ALARA (As Low as Reasonably Achievable) as the standard of limiting radiation exposure, with a career maximum of 600 mSv. The CO2 in the atmosphere of Mars may provide sufficient protection from Galactic Cosmic Rays and solar flare protons. However, astronauts bound for Mars will still experience a substantial amount of radiation exposure during the six-month transit from Earth to Mars, thereby effectively reducing the amount of radiation that can safely be absorbed while living on the planet’s surface to a maximum of 300 mSv. For this reason, additional radiation shielding is necessary, particularly for long-term settlement. Local resources, such as Martian regolith, can serve that supplementary role. Combining functionally graded materials (FGM) with regolith will produce an inherently robust compound that can be 3D printed.
FGMs add natural illumination to a structure through the properties of their chemical makeup, which consists of a ceramized geopolymer concrete (GP) that shares structural properties comparable to that of transparent glass. Mechanical joints and chemical bonds of traditional adhesives do not guarantee a seamless seal, an aspect that is crucial for pressurized habitats. Furthermore, FGMs will not require leakage maintenance.
Researchers at Penn State University conducted experiments on improving FGMs in 2018. Their studies mixed GP pastes with glass sheets and aqueous activators, heating the formed material to 850oC. The results indicated that the interface between the concrete and transparent glass was smoother when the initial materials had similar coefficients of thermal expansion (CTE). Additionally, the tests found by increasing the number of layers for a given length of a structure, while making precise incremental changes to the material composition, the significant volume expansion between layers can be reduced, thereby minimizing the likelihood of crack formation. The research also found that by adding trace amounts of glass powder, a minimum of 5%, to the GP-rich layers, additional strength can be garnered to further prevent cracking between surfaces. The majority of components of the GP paste are SiO2, Al2O3, CaO, Fe2O3, MgO, and SO3, which are available for harvest on Mars’ surface.
Additional Preliminary Kuja sketches can be found in Kuja Drawings File.
3D-Printed Habitat External Perspective
The presence of humans on site will expedite the construction process for the permanent habitat. The crew outfits the first regolith dome and assembles airlocks, eventually moving into their new Martian home. The initial temporary habitat is turned into a scientific laboratory, while the rocket will be the main central hub for restrooms, storage, and experimental spaces. The crew is not encouraged to spend much time in the rocket as aluminum and polyethylene become less effective methods of radiation shielding on Mars’ surface (24).
The diameter of each dome derives from the constraints of the robotic 3D printing arm. Since printing begins before the arrival of the crew, the arm needs to reach the outer boundary of the dome without assistance. Therefore, each dome is 18 m in diameter. One and a half meter thick regolith walls allow for 14 m, in diameter, or 153.94 m2, of livable space. The floor is recessed into the surface by 1.5 m for additional structural supports and stands at 8.2 m above the surface. The three main drivers of habitat design were nature, circulation, and functionality.
The layout of the typical dome consists of two full height floors and one mezzanine. The mezzanine provides three points of egress leading towards another habitat dome, greenhouse, or a safe means to exit onto the surface of Mars. Horizontal and diagonal notches are designed to be left vacant in the interior wall section to allow for multiple configurations of the ramp system. This system is intended to provide the crew with multiple levels of egress within the dome itself. The circulation ramps can be laid in multiple configurations due to the aforementioned notches. Thereby enabling an additional level of flexibility to suit the unique needs of each dome. The inner wall promotes the primary circulation route, emphasizing the 3D printed fractal patterns, thereby giving crew members the impression of a leisurely walk in nature.
The circulation design driver challenges the traditional approach of configuring the standard geodesic domed massing of previous extraterrestrial habitation designs. Through elevation, a series of iterations assesses the pressurization of the volume. That being methods of standardized domed masonry and the vertical space required for a walking path. The ideal form for a habitat is a half sphere resting atop the surface of the landscape. A perfect sphere, however, limits the extent through which the circulation ramp can access the upper levels. This is due to the walls’ innate desire to curve at a steep angle. Instead, vertical walls that support a domed roof help to maintain the proper level of pressurization, while providing adequate space for creative measures, such as a circulation ramp, to succeed.
Additional Details on the 3D-Printed Habitat can be found in the 3D-Printed Habitat Plans and Section File.
4. Cultivation Framework
Kuja Plant Selection Sketches
The fundamental purpose of establishing a greenhouse environment for the ARES mission is to enable and sustain a level of autonomy from Earth. Crops that will be grown on Mars serve three functions: produce supplementary oxygen, reduce CO2 levels, and generate nutritional value for the crew and other greenery. The Russian Salyut Missions, an evolution from their forerunner, the Soyuz Missions, were a series of Soviet Space Stations launched between the years 1971 and 1982. Although fostering a domain to research information on vegetational growth patterns in micro-gravity was not the primary focus of the Russians during this period, valuable information was still obtained regarding this matter:
1) Effects of spaceflight exposures on seeds and plants in natural dormancy or activation
2) gravitational perception and growth of plants in weightlessness
3) plant cultivation technologies
4) selection of plant sets for bio-technical life support systems
Further studies have been conducted more recently aboard the ISS and in environments designed to replicate the Martian soil. The data from these studies are intriguing, yet they do not attempt to solve the problems that an acidic and low-gravity environment, such as Mars, possesses. These problems are as follows:
1) A lack of sustainable nutrients for the crew and plants themselves
2) A lack of naturally occurring habitable conditions (growth space, soil, air temperature and pressure)
3) A lack of water and natural sunlight
The following vector optimization methods seek to provide solutions to said problems:
1) Nutritional Enhancements: Martian regolith will need to act as a solvent, absorbing additional nutritional enhancements to alter its chemical pH level. Due to the higher levels of Iron, an alkaline metal, the pH level of the soil on Mars is higher than that on Earth, which has an average level of 7.2. Introducing ammonium-containing fertilizers will lower the pH level of the soil over time, a substance that can easily be fabricated using compost.
2) Nitrogen Fixation: Introducing secondary doses of Nitrogen through ammonium-containing fertilizers can strategically boost the Martian regolith to the necessary level needed to sustain the Nitrogen Fixation process. Without Nitrogen Fixation, plants, and other organisms will not be able to grow adequately. Microorganisms such as diazotrophs naturally conduct this procedure, thereby expediting the bio-synthetic portion of the Nitrogen Fixation cycle, an essential aspect of cultivating organic compounds. Additional nutrients can be incorporated into an ammonium-containing fertilizer to further develop the number of vitamins that can be provided to the plants in Martian greenhouses. Vegetation that is more comfortable in extreme conditions, such as Alfalfa, is an excellent way to supercharge the regolith, resulting in healthier and more tenacious plants.
3) Addition of Extremophiles: Extremophiles are microscopic organisms that have significant biological characteristics, allowing them to survive in extreme conditions. Although there are millions of genetic strands among billions of organisms, a select few traits could be revolutionary. A series of experiments, involving bio-domes as a constant, revealed two key genes as being highly useful. Those being pyrococcus furiosus + superoxide reductase. A process of gene splicing these two specified genes into the selected plants’ biochemical makeup would allow a higher level of resistance to cold temperatures, as well as introduce a tendency for the plant to rely less on consistent watering practices. This is possible through synthetically reducing cytosolic Reactive Oxygen Species (ROS), which if left unintended will result in cell death due to a high level of stress. Both traits would be considered necessary to make a sustainable colony in the Martian environment.
4) Soil: The Martian soil differs throughout the varying regions of the planet, but generally is a clay-based material that is dense and thick. Implementing strategies in order to transform the soil into a sandy loam-like consistency will pay dividends for the future of a Martian colony. This process is designed around growing two separate plants within a confined region of regolith. The difference in growth patterns between the two plants harrows the soil after several growing cycles, resulting in a basin that future rotations of crops adapt to more effectively. Additional components can be brought from Earth such as charcoal and trace amounts of organic matter to replicate the fertile success observed in terra preta. Pottery fragments also have a direct positive correlation with the level of fertility in compost soil akin to terra preta, a practice that will more than likely naturally develop for habitual use.
5) Lighting: High-efficiency LED lights will be a staple in Martian greenhouses due to the lack of natural sunlight. An individualized lighting system allows for each section of a greenhouse to be customized for the specific plants being grown. A wide variety of commercial grow lights are applicable in this scenario. Recent studies on vertical farming and hydroponic research have shown that DC Lighting apparatuses have a higher yield percentage, while also supplying the plants with a healthier source of energy. Technology demonstrated in vertical farms constructed by Kalera showcases this interaction on Earth, potentially leading to promising results on Mars. In addition to an efficient lighting system, heating filaments installed under the greenhouse will provide further warmth, a necessary aspect when the average temperature of Mars around the equator is 0oC.
The selection process for which plants should be attached to the mission planning process was an extensive process. Details regarding why each plant was chosen, as well as specific strengths and weaknesses of each crop can be found in the Cultivation Framework file.
Interior Greenhouse Perspective
The prefabricated greenhouse modules will be constructed on Earth and shipped to the Martian surface aboard MARS. The cargo bay present in the rocket is designed to hold one hundred tons of contents within a 512 cubic meter chamber. More than enough space is available to transport and deliver two prefabricated greenhouse modules in each rocket. Thereby allowing three fully functional prefabricated greenhouses to be available for use on-site when the manned ARES II mission touches down in 2035.
The prefabricated greenhouses themselves are designed in a simple manner, engineered to promote an effortless repair process. Silicon caulk is utilized to minimize the risk of external air infiltration into the interior space, while a series of galvanized steel screws meld the structural members together, resulting in a finished architectural shell. The screws and joints used in the design process can be replicated and 3D printed on site if need be.
Thermo-insulating pads are installed on top of a two-piece foundation, which can be readily accessed through the removal of an aluminum grated floor. Solar trees and secondary level supports are easily dismantled if access is needed, allowing for maintenance and cleaning of the fiberglass planter boxes. Finally, exterior solar panels and hanging DC LED lights complete the space. The 3D printed greenhouses will be constructed in the same manner as the shell of the permanent habitats.
Additional information regarding the construction of the prefabricated greenhouses can be found in the Prefabricated Greenhouse Plans and Sections file.
5. the future of ares
ARES Colony Perspective
The methods utilized in ARES will be essential for the future of human exploration. New strategies regarding 3D-printing technology are constantly being innovated upon, leading to perpetual shifts in the design approach. More efficient procedures will inevitably push the boundaries of what is possible in the mission planning process. This includes development in the robotic, biophilic, cultivation, psychological, architectural, and propulsion systems.
Advancements in each of these fields enable longer duration missions in more extreme environments. Mars is an unforgiving landscape and ARES is an attempt to push the envelope of what is possible there.
Challenges are created to elevate the threshold of what is reasonably achievable in the near future. ARES is a mission tasked with a seemingly un-accomplishable goal to maintain human life on a foreign planet consecutively for over seven years. The set parameters have forced the habitat to be constructed in a more robust manner. Certain design decisions took precedence over others, such as prioritizing new methods and material compositions to reduce the amount of harmful radiation exposure. This, as well as developing an architectural plan that is easy to physically construct using 3D-printing equipment while allowing a high degree of in-situ flexibility, is what sets this proposal apart.
Space exploration is going to be the focal point of human civilization this century. Establishing a research station on the moon is obtainable in this decade. Mars is next, but the set of challenges attached to conquering the red planet, from a scientific achievement standpoint, are much more challenging. The distance from Earth results in a mission to Mars consuming more fuel, having a longer transit time, and experiencing longer communication delays. The average temperature of the Red Planet, paired with the scarcity of water, limits the amount of feasible site locations. The lack of a potent atmosphere increases the need for radiation shielding. Homesickness, sandstorms, lack of light, unsuitable pressure levels, isolation confinement, lower gravity, and an abundance of other problems await the first crew to Mars. These are all obstacles that can be overcome with proper preparation and high-level human-centered designs.
ARES has proposed innovations for solutions to all of the challenges that Mars presents. Future projects will look to improve on the foundation that ARES and other research-based proposals have built, as the quest to inhabit Mars continues to grow closer.
This project is currently pending publication. A more detailed outline of each facet of the mission planning process can be found in the Anthropocentric Habitation of Mars Through Parametric Design Paper.
This project was initially developed under the restrictions of RASC-AL RASC-AL (nianet.org)
This project was selected to be featured in the 2023 ICES conference in Calgary, Canada ICES | International Conference on Environmental Systems
A final thank you to my team members (Erin Quigley, Chris Hisle, Chi Lan Hunyh) who helped develop the project and paper to an elevated scientific standard for what is attainable regarding human space flight in the coming decades.