AENEAS
A PLAN FOR A SUSTAINABLE, PERMANENT 1000 PERSON SETTLEMENT ON MARS
INTRODUCTION
A permanent human settlement on Mars of a thousand people does not simply pop into existence, but necessarily evolves from a smaller settlement, and if successful, continues to grow beyond a thousand inhabitants. Certainly, to be successful as a remote, isolated community in the harsh environment of Mars, such a settlement would need to become as self-sufficient as possible, as rapidly as possible, and would need to grow well beyond the one thousand inhabitant mark to fully achieve this goal.
Therefore, it is essential that the community immediately establish a productive and sustainable economy. The initial focus must be to create a solid economic foundation, and the foundation of any successful, sustainable economy is primary productivity, which on Mars would be defined as energy production, mining, and farming. Reliance on in situ resource utilization (ISRU) without long distance travel, and the use of only existing technologies, are key aspects of this plan.
Siting of the settlement would be on, or very near, the equator. This location provides the warmest surface temperatures, reducing heating energy requirements; the highest levels of solar insolation, reducing photovoltaic array and solar thermal array size requirements; and provides the highest level of surface velocity for boosting rocket launches, reducing rocket fuel requirements, at least in the long term. It should be noted that the largest, and perhaps only, drawback to an equatorial location is that this latitude represents regolith water content as low as 2% by weight¹.
There are several interesting sites. There is one just west of the southern end of Echus Chasma right on the equator. This location, with a relatively neutral altitude, provides a centralized location to several astounding areological formations. It’s on the edge of the Tharsis bulge with Pavonis Mons due west. Fortuna Fossae, Ascraeus Mons, and Tharsis Tholus to the northwest, Echus Chasma just to the northeast. Hebes Chasma to the east, Perrotin crater, Ophir Chasma, and Candor Chasma to the southeast, and Tithonium Chasma to the south (Figure 1).
Other potential sites with interesting areological formations are uplands overlooking Baetis Chaos, Orson Welles Crater, Oxia Chaos, Da Vinci Crater, Hydraotes Chaos, Nicholson Crater, Medusae Fossae², or Amazonis Mensa.
ECONOMIC ASPECTS OF THE AENEAS SETTLEMENT
The Aeneas (/ɪˈniːəs/) settlement would first and foremost establish a mining, industrial manufacturing, and farming community for the purposes of establishing a sustainable, permanent settlement on Mars. Mining and industrial manufacturing enable the construction of settlement infrastructure, while farming provides food and clothing. Success in laying out the settlement infrastructure will enable the later establishment of the Mars Science and Technical Innovation Institute, which, beyond working to solve technical issues for the Aeneas community itself, would be working to solve issues for the general human settlement of Mars. It would also contract to house visiting scientists from Earth-based universities and research institutions such as NASA and ESA, providing them room and board, laboratory space and equipment, and a base from which to operate on Mars, with extensively more safety and comfort than could be provided with temporary, remote shelters, and at greatly reduced mission cost. Commercialization royalties from patents and technologies developed at the Institute can provide another source of return on investment (ROI) income. Subscriptions to Mars climate and geological data libraries, geological samples export, precious metals and minerals export, value-added product export (e.g., jewelry), and pleasure tourism are all potential sources of Earth-originating cash flow, or ROI. The Aeneas settlement would also, necessarily, operate as a spaceport with spacecraft refueling, maintenance, and repair capabilities, as well as providing crews with rest and relaxation opportunities. Further, due to Mars proximity to the asteroid belt, an established Martian spaceport stands to profit from providing spaceport services to asteroid mining ventures.
Aeneas is envisioned as incorporated, with shareholders, and with community-members being awarded stock grants. This provides residents with a sense of ownership and a vested interest in the future success of the settlement. Political management would be accomplished with a democratically elected governance board, who would in turn recruit and appoint qualified experts (technocrats) to manage specific sectors, projects, and activities within the community and economy. While management hierarchies have some benefits, it has been demonstrated that flatter work hierarchies provide individuals with a stronger sense of empowerment, encouraging creativity and problem solving, all of which benefit the community³. It is, therefore, suggested that the community be organized and led in this way.
This would most certainly be a planned economy, and it can be argued that a hybrid economic model makes the most sense. All products and services required by all the community’s inhabitants would be provided by the community to its permanent members. Centralized control of infrastructure development and management of life sustaining activities is simply more efficient and secure. A basic income would be paid to each permanent resident, which would allow them to purchase their food and clothing. Life support, water, shelter, all levels of education, and basic medical care would be managed as the public sector of the economy. Those working in the public sector would be paid salaries above the basic income by the community. There would be no private real property ownership, but private ownership of personal possessions, objects of value, and personal services would be owned and traded as the private sector of the economy. Commercial space would be rented from the community to allow for small business entrepreneurs, such as restaurateurs, baristas, craftsman, artists, and personal services vendors to produce, sell wares, and provide services. Those working in the private sector would earn their salaries above the basic income by charging for their goods and services. Once the community has met its investment obligations, surplus earnings can be directed toward settlement expansions and improvements, or even in providing shareholders (which include community members) with a dividend.
Primary Production — Energy, Mining, Farming
The first technical challenge, beyond basic life support on the surface of Mars is energy production. An abundant energy supply is the key to unlocking Mars for humankind, because energy is the limiting factor for industrialization. The industrialization of Mars is essential to making it habitable, and with adequate energy, industrial processes can be driven to solve nearly any technical problem.
Energy can initially be provided with imported Radioisotope Thermoelectric Generators (RTGs), solar photovoltaic, and solar thermal dynamic power generation equipment. These sources would be followed later with the development of in situ geothermal energy production using imported drilling and imported or repurposed power generation equipment.
In the earliest stages of development, electric power will be provided with RTGs. This will provide the electricity for lighting, heating, and life support for the initial teams, while the solar photovoltaic system, including a relatively small battery storage system is assembled. Initially, the RTGs can be stationed in crudely excavated pits, covered with insulated inflatable dome tents, utilizing their waste heat to sublimate water ice in the soil subsurface. Water vapor released from the soil in this way can be collected with Pressure Swing Adsorption (PSA) equipment stored within the tent, the liquid water shunted to insulated, pressurized storage tanks for use as potable water, energy storage, and heat distribution to temporary living quarters.
A very large solar array can be constructed. Imported thin-film panels would be used initially until PV manufacturing, such as inkjet-printed, thin-film perovskite (calcium titanate) solar cells⁴, is underway. The panels are aligned on long guide rails upon which rides a robotic cleaner. The robotic cleaner uses an air compressor to blow dust off the panels on an ongoing scheduled basis to keep them clean and operating efficiently. The robot’s control system uses a wind direction sensor to stage the beginning of a cleaning cycle at the most upwind location and moves progressively downwind to optimize the cleaning process.
The next phase would be construction of a solar thermal dynamic power generation⁵ facility utilizing compact linear Fresnel reflectors and multiple absorbers to heat water stored in insulated, pressurized tanks. Pressurized hot water can be flashed for steam turbine electric generation, with the waste heat being circulated through inflatable hydroponic greenhouses and temporary living quarters. Solar thermal has the distinct advantage of being able to store thermal energy using in situ resources, such as water or salts, allowing for electric generation around the clock. Once the initial settlement has been secured with enough available electricity, heat, and water, work on boring geothermal⁶ wells can commence. Once geothermal power is secured, the settlement can continue expansion and development of its industry.
The second technical challenge is water. It would be enormously beneficial if a site can be identified that has significant quantities of subsurface water ice at, or near, the surface, and ongoing Mars reconnaissance seems to indicate that water ice and mineral hydrates are relatively abundant and widespread⁷. This plan calls for the eventual extraction of approximately 21 million metric tons of regolith, which at a conservative estimate of 2% by weight water, would yield 420 thousand metric tons of water. Closed-loop recycling of water used for life support is essential. PSA equipment can be used to regulate atmospheric gas and water content concentrations within the complex. Ongoing production of water will be necessary to replace water lost due to electrolysis and other industrial uses.
Water, while obviously necessary for human consumption such as drinking, cooking, and hygiene, is also necessary for heat distribution into greenhouses and living areas, for agricultural and aquacultural endeavors, exercise, and entertainment, as well as energy production (heat storage, steam turbine electric generation, geothermal circulation). Water is also crucial for chemical and manufacturing industrial uses. Water will be used for electrolysis to produce hydrogen and oxygen,
a) 2H₂O → 2H₂ + O₂
forming the basis of industrial chemical production.
Initial mining activity will focus on regolith extraction and processing, particularly heating the regolith to chemically reduce metal oxides, perchlorates, sulfates, carbonates, and nitrates. This processing includes gas capture, such as water vapor, oxygen, nitrogen oxides, hydrogen sulfide⁸, sulfur dioxide, etc., utilizing PSA equipment.
By developing the techniques to process generalized Martian regolith into a series of useful products, the settlement puts itself in a position to industrialize Mars far more rapidly than could be done through the typical mining processes of exploration and identification of individual mining sites rich in single minerals. By creating this economic stability, later identification of mineral rich sites merely represents a windfall, rather than a prerequisite to building a sustainable economy.
Combining mining operations directly with habitat construction is the most efficient use of energy and labor. Vertical shafts bored to extract regolith are to be lined with 3D printed sulfur concrete cylinders, topped with 3D printed sulfur concrete domes for utilization as subsurface habitats. Horizontal mining shafts lined with 3D printed sulfur concrete shoring provide passageways between the vertical sections. These subsurface habitats will provide far more protection from extreme surface temperatures, meteorites, and radiation than would surface structures.
Vertical Shaft Sinking Machines (VSM)⁹ are used to bore vertical shafts in the regolith (at least the smaller diameter shafts). The regolith is processed by grinding it and feeding it through an electric rotary kiln. Gases from the kiln are collected and separated via pressure swing adsorption (PSA). The VSM 3D prints a continuous shaft wall as it sinks it into the excavation. Once a vertical shaft has been completed, the boring machine 3D prints a sulfur concrete¹⁰ floor. The VSM then moves to another shaft location and passageways between boreholes are horizontally bored with tunnel boring machines, the walls shored with 3D printed sulfur concrete. A dome printing machine then moves in over the completed cylinder and prints a dome on top of the subterranean cylindrical structure¹¹. Boreholes of various diameters and depths are created in this fashion.
Generalized Martian soil constituents, in order of content, based on data from Spirit, Opportunity, and Curiosity rovers, are silicon dioxide (SiO₂), iron oxides (FeO*), aluminum oxide (Al₂O₃), magnesium oxide (MgO), calcium oxide (CaO), sulfur trioxide (SO₃), sodium oxide (Na₂O), titanium dioxide (TiO₂), phosphorus pentoxide (P₂O₅), chlorine (Cl), potassium oxide (K₂O), chromium oxide (Cr₂O₃), manganese oxide (MnO), nickel (Ni), zinc (Zn), and bromine (Br)¹²,¹³ (Figure 2).
Additionally, there have been reports of sulfates¹⁴, nitrates¹⁵ and borates¹⁶ in the regolith.
Excavated regolith will be processed by crushing, dry-grinding, and running it through a continuous feed, electrically heated rotary kiln, heating it to temperatures above 500 °C to decompose perchlorates¹⁷,¹⁸,
a) [Ca(H₂O)₄](ClO₄)₂ → Ca(ClO₄)₂ + 4H₂O
b) Ca(ClO₄)₂ → Ca(ClO₄)₂ (melt)
c) Ca(ClO₄)₂ ↔ CaCl₂ + 4O₂
oxides, sulfates, carbonates, and nitrates driving off gases and water vapor. The gases are processed through a series of PSA equipment. The remaining regolith can be sifted and sorted, using various ore processing techniques, such as magnetic separation for iron rich minerals, and sifting to produce aggregate mixtures suitable for producing 3D printed sulfur concrete.
Covering vertical shaft regolith excavations with inflatable tents will allow work to progress regardless of surface conditions, protecting personnel and equipment from dust and extreme cold, allowing work to continue even during dust storms, and facilitating the capture of water vapor, and other gases released during mining with PSA equipment.
Significant levels of oxygen (O₂) will also be released from oxides, perchlorates, carbonates, nitrates and borates present in the regolith. This is also easily captured with PSA equipment.
Hydrogen sulfide (H₂S) released from the regolith during kilning would be collected with PSA equipment and processed with the Claus process,
a) 2H₂S + 3O₂ → 2SO₂ + 2H₂O
b) 4H₂S + 2SO₂ → 3S₂ + 4H₂O
to produce elemental sulfur (S₈). This sulfur is to be used to produce sulfur concrete for 3D printed construction, particularly vertical and horizontal shaft shoring walls and covering domes (35% sulfur, 65% aggregate)¹⁹.
Large amounts of sulfur dioxide (S₂) can be expected to be generated through thermal decomposition of sulfur compounds in the regolith. Catalytic reduction of sulfur dioxide with hydrogen²⁰,²¹,
a) 3SO₂ + 7H₂ → 6H₂O + S₂ + H₂S
can also be used to produce elemental sulfur for use in sulfur concrete production with the hydrogen sulfide shunted to Claus process.
Additionally, some sulfur dioxide can be processed into sulfuric acid via the contact process,
a) 2SO₂ + O₂ → 2SO₃
b) H₂SO₄ + SO₃ → H₂S₂O₇
c) H₂S₂O₇ + H₂O → 2H₂SO₄
for industrial uses.
Nitrogen oxides (NOₓ) are also likely to be released from the regolith during heating. PSA equipment can be used to capture these gases for later conversion into nitric acid for chemical use, nitrates for fertilizers, or Selective Catalytic Reduction (SCR) (Tungsten oxide catalyst),
a) 4NO + 4NH₃ + O₂ → 4N₂ + 6H₂O
b) 2NO₂ + 4NH₃ + O₂ → 3N₂ + 6H₂O
c) NO + NO₂ + 2NH₃ → 2N₂ + 3H₂O
can be used, which injects ammonia into the nitrogen oxide gas at relatively low temperatures of 300 to 400 °C, converting the nitrous oxides (NOₓ) and ammonia (NH₃) to nitrogen (N₂) and water (H₂O). In this process, 80 to 90% of the nitrogen oxide is converted to nitrogen, which can be used for the complex’s atmosphere.
While hydroponic farming, commonly used for growing crops like lettuces, spinach, strawberries, tomatoes, peppers, and herbs will be important initially, a wider variety of crops can be grown in soil. One important consequence of regolith processing will be the thermal decomposition of perchlorates, chemical reduction of oxides, and removal of metal ores and salts, leaving behind mineral content suitable for mixing with composted organic material to create soil suitable for edaphon, and consequently farming. Enriched soil produced in this way can be used for farming a wider variety of crops, as well as those that aren’t suited for hydroponic farming. The following table provides a sample methodology for agricultural production with the goals of providing suitable crop rotation, production of animal feed, adequate caloric intake and balanced nutrition, while providing enough variety to keep it interesting and delicious.
Algae, particularly Chlorella, can be grown in bubble column photobioreactors, fertilized with human and animal waste and Mars atmospheric carbon dioxide (CO₂) to produce oxygen (O₂). Excess Chlorella can be used as feedstock for tilapia and/or shunted to biodigesters to produce methane and compost.
Bamboo, a rapidly growing, renewable crop, can be farmed to produce cellulose fibers and lignin. The cellulose fibers can be used to produce rayon, which can subsequently be used to produce various textiles as needed. The lignin, a phenylpropanoid-based biopolymer, can be used as a substitute source for phenol in most of phenol’s industrial applications such as phenolic resins, surfactants, epoxy resins, adhesives, or polyester. It can be processed into a variety of products, not the least of which are activated charcoal and carbon fiber²².
High productivity animal production such as vermiculture, cricket farming, and brine shrimp can produce high quality proteins, which can be converted to more palatable forms of proteins for humans when fed to chickens (both for egg and meat production), or aquacultural varieties such as catfish and rainbow trout.
Apiary in greenhouses will ensure successful plant pollination and provide honey.
Note that first generations of chickens, bees, crickets, and fish can be transported to Mars as cryopreserved embryos, which can then be thawed, incubated, and hatched.
Human, animal, plant, and food waste will be composted in biodigesters, producing both methane and compost. The compost is mixed with processed regolith to create enriched soil for farming, while the methane is compressed for fuel or converted to ethylene.
In these ways, biotechnologies, biogeneration, and biorefinery operations allow recycling of biomass and its use as source material to produce food, clothing, and a myriad of valuable organic products.
Secondary Production — Synthesis, Materials, and Manufacturing
While it is beyond the scope of this paper to define the entire structure of an industrialized Mars, it is important to note that the basis of secondary production is the chemical industry. Recommended guiding precepts for the development of an economically viable and sustainable chemical industry on Mars can be borrowed from the Green or Sustainable Chemistry movement, and would be: a preference for the prevention of waste, over treatment or cleanup; a preference for processes favoring atom economy over yield; a preference for lower toxicity methods and substances; a preference for energy efficiency and methodologies for heat recovery and cogeneration; a preference for renewable feedstocks when practical; a preference for the reduction of derivatives; a preference for catalysis over stoichiometric reagents; a preference for the production of easily recycled materials with inert decompositional products; continual analysis, in-process monitoring, and control for the prevention of the formation of hazardous substances, waste production, or energy loss; and, a preference for substances and processes which minimize risks of accidents, such as unintended releases, fires, or explosions.
As previously discussed, water electrolysis will produce hydrogen and oxygen,
a) 2H₂O → 2H₂ + O₂
forming the basis for industrial chemical production.
The Sabatier reaction can then be used to catalyze (Al₂O₃ catalyst) hydrogen and atmospheric carbon dioxide into methane and water,
a) CO₂ + 4H₂ → CH₄ + 2H₂O
Methane production is primarily for fueling Earth return vehicles²³, but excess methane from rocket fuel production and biogas digesters can be oxidized to produce supplemental heat for the steam turbine electric generators in instances of low solar availability, such as during dust storms, until geothermal energy production is achieved.
Additionally, oxidative coupling of methane (OCM) (LiMgO catalyst) can be used to produce ethylene,
a) 2CH₄ + O₂ → C₂H₄ + 2H₂O
Reaction inefficiencies lead to some production of carbon dioxide and carbon monoxide. The carbon dioxide can be shunted back to the Sabatier process and the carbon monoxide can be used in the Boudouard reaction,
a) 2CO → CO₂ + C
to produce elemental carbon and carbon dioxide. The carbon dioxide is again shunted to the Sabatier process with the elemental carbon being used to produce carbon electrodes for the Hall-Héroult process to produce aluminum.
Ethylene gas can then be polymerized into polyethylene with the Ziegler-Natta catalyst titanium trichloride (TiCl₃). Low- and high-density polyethylene (LDPE, HDPE) can be used for the manufacture of piping, water and chemical storage tanks, electrical conduit and wire insulation, and radiation shielding. Boron isolated during regolith processing can be added to HDPE at 5% by weight to enhance its radiation shielding capabilities (5% Boron Enhanced HDPE)²⁴.
The Martian atmosphere, while primarily composed (95.32%) of carbon dioxide (CO₂), is about 2.7% Nitrogen (N₂). PSA equipment can be used to concentrate pure nitrogen gas from the atmosphere. Nitrogen and hydrogen can be fed into the Haber-Bosch process (Fe₃O₄ catalyst),
a) N₂ + 3H₂ → 2NH₃
to produce ammonia (NH₃).
As previously discussed, some ammonia is used in Selective Catalytic Reduction (SCR) to convert nitrogen oxides to nitrogen. Additional ammonia would be used in the modified Solvay (Hou’s) process to produce sodium bicarbonate,
a) NaCl + CO₂ + NH₃ + H₂O → NaHCO₃ + NH₄Cl
The sodium bicarbonate is heated to produce sodium carbonate,
a) NaHCO₃ → Na₂CO₃ + H₂O + CO₂
Sodium carbonate (Na₂CO₃) can be used for glass making, water treatment, and aluminum processing.
Sodium carbonate (Na₂CO₃), silicon dioxide (SiO₂), aluminum oxide (Al₂O₃), and boron trioxide (B₂O₃) can be combined to manufacture borosilicate glass, which has very low coefficients of thermal expansion, high resistance to thermal shock, high chemical durability, high light transmission, pristine surface quality, and blocks neutrons due to its boron content. Borosilicate glass can be used for bottles, windows, cookware, solar panels, mirrors, evacuated tube collectors, electrical insulators, lighting fixtures, laboratory equipment, medical equipment, telescope mirrors and optics, and fiber optics.
Twenty-six percent sodium chloride (NaCl) brine can be processed using chloralkali membrane cells to produce sodium hydroxide (NaOH), chlorine gas (Cl₂), and hydrogen (H₂),
a) 2NaCl + 2H₂O → Cl₂ + H₂ + 2NaOH
The sodium hydroxide (NaOH) can be used in the Bayer process to purify alumina from crushed regolith. The chlorine and hydrogen can be reacted with UV light,
a) Cl₂ + H₂ → 2HCl
and dissolved in water to produce hydrochloric acid (HCl).
In Bayer process 1,
a) Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O
crushed regolith (which appears to contain around 9 to 10% alumina by weight) is hydrated and mixed with sodium hydroxide then heated in a pressure vessel to around 200 °C. Calcium oxide, which is already present in the regolith induces silica to precipitate as calcium silicate. This mixture is filtered to remove undissolved compounds and concentrate the sodium aluminate. Initially the sodium aluminate has carbon dioxide bubbled through it (Bayer process 2),
(b) 2NaAlO₂ + 3H₂O + CO₂ → 2Al(OH)₃ + Na₂CO₃
to create aluminum hydroxide crystals to seed slurry for ongoing Bayer process 2,
c) 2H₂O + NaAlO₂ → Al(OH)₃ + NaOH
Then the aluminum hydroxide is desiccated with heat,
d) 2Al(OH)₃ → Al₂O₃ + 3H₂O
to produce pure alumina. This alumina can then be processed with the Hall-Héroult process,
a) Al2O₃ + 3C → 2Al + 3CO
to produce pure aluminum. The carbon monoxide can be shunted back to the Boudouard reaction for carbon production, or to the Fischer-Tropsch process (Fe catalyst),
a) 3H₂ + CO → CH₄ + H₂O
to create additional methane. The aluminum can be used to produce castings, extrusions, wires, and powders, all of which can be used for construction of structures, vehicles, machines, electrical wiring, and for 3D printing.
The Alumina Refinery Residues (ARR), or red mud, which is highly caustic due to sodium hydroxide (NaOH) content can be neutralized using hydrochloric acid (HCl)²⁵,
a) NaOH + HCl → NaCl + H₂O
This will allow it to be safely handled for further processing. It can be processed into pavers and bricks for interior construction²⁶, or further refined into purified silicon dioxide (SiO₂) for glassmaking.
A thermal reduction process with silicon can be employed to convert magnesium oxide to magnesium vapor,
a) 2MgO + Si → SiO₂ + 2Mg
which can be condensed into pure magnesium. The silica is combined with calcium oxide to form calcium silicate,
a) SiO₂ + CaO → CaSiO₃
Magnesium can be used in alloying aluminum and steel, and in the production of titanium.
Steel can be produced using iron compounds separated from the regolith using magnetic separation and processed using a Direct Reduced Iron (DRI) methodology, such as the HIsarna process Cyclone Converter Furnace (CCF) and Smelting Reduction Vessel (SRV) to produce sponge iron, where hematite (Fe₂O₃) becomes magnetite (Fe₃O₄) by reduction with carbon monoxide (CO) and hydrogen (H₂),
a) 3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂
3Fe₂O₃ + H₂ → 2Fe₃O₄ + H₂O
magnetite (Fe₃O₄) becomes ferrous oxide (FeO) by reduction with carbon monoxide (CO) and hydrogen (H₂),
b) Fe₃O₄ + CO → 3FeO + CO₂
Fe₃O4 + H₂→ 3FeO + H₂O
ferrous oxide (FeO) becomes sponge iron (Fe) by reduction with carbon monoxide (CO) and hydrogen (H₂),
c) FeO + CO → Fe + CO₂
FeO + H₂ → Fe + H₂O
for conversion into steel in an Electric Arc Furnace (EAF). Steel can be used for framing, construction, piping, machines, and wire or powder for 3D printing.
The examples above, such as the production of methane, plastics, aluminum, magnesium, steel, and glass, are merely examples of the chemical synthesis and secondary production capabilities that will be necessary in creating a sustainable settlement on Mars. Equipment shipped from Earth to set up these capabilities would only be for small scale production. Once initial production is established, the produced material can be used to scale up machinery and capability, creating a positive feedback loop of increasing industrial scale. The Aeneas settlement is designed to provide the energy and industrial spaces necessary to set up chemical and industrial processing, as well as, manufacturing.
ENVIRONMENTAL ASPECTS OF THE AENEAS SETTLEMENT
Aeneas is intended to be a walkable community for a thousand permanent residents in a climate-controlled, underground system of tunnel-connected, cylindrical living structures of varying size containing an atmosphere at a pressure of 81.2 kPa (approximating an Earth altitude of 1600 m above mean sea level), composed of a mixture of 21.00% oxygen, 78.75% nitrogen, and 0.25% water vapor at a steady background temperature of 20 °C, all of which is intended for maximum health, safety, and comfort of its residents.
Below ground construction provides living areas with far greater radiation shielding and safety from small meteorites than is possible with surface construction without extensive and expensive remediation. Additionally, it provides far greater thermal efficiency by reducing heat loss to the frigid Martian atmosphere. The goal would be to develop the living areas such that they would provide an average radiation dosage limit of <=2.0 mSv/y. As normal Earth background is ~2.4 mSv/y, this will help compensate for higher radiation doses experienced during planetary transfer and surface excursions while living on Mars.
There would be few if any windows or skylights in the settlement complex. Most of the complex is below grade, and windows are both expensive and dangerous, as they are difficult to seal, and provide potential points of decompression failure and increased levels of radiation exposure. Additionally, Martian natural light is dim enough to compare with significant overcast on Earth, meaning naturally lit spaces would be dark and dreary. To that end, all interior spaces would be brightly lit with energy conservative LEDs, using broad-spectrum LEDs suitable for plant growth in public spaces and controlled to mimic a natural day/night cycle. This will help promote plant growth, and to prevent psychological problems, such as Seasonal Affective Disorder (SAD), or problems associated with the disruption of natural circadian rhythm.
Views outside the complex can be provided on high-definition screens (virtual windows) which broadcast from stationary or robotic, mobile cameras on the surface. The actual night sky over the complex could be projected onto the undersurface of the Campus Martius (/ˈkampəs/ /ˈmär-sh(ē-)əs-/) central dome to provide a place to observe the night sky and reinforce the feeling of being outdoors.
Given the harsh and dangerous surface conditions, actual surface excursions would be rare for most inhabitants, as it would generally be limited to individuals involved in necessary construction and maintenance tasks, scientific and exploratory expeditions, and tourism excursions.
The hexagonal-tiled, fractal-like pattern of the complex’s layout keeps it compact, simplifies construction procedures, and minimizes the required equipment. As the same pattern repeats itself, it makes it easier to seal off sections both during construction or in disaster events and provides redundancies. If each sector has the technical capability of supporting twice its normal population, then it is easy to safely accommodate displaced individuals in the event any section in the complex needs to be evacuated. Any technical system can fail, so redundancies are required. Passive systems are preferred when possible, as they tend to have greater stability and are easier to manage with less required intervention. Having multiple sources of resources is also useful. An example would be water electrolysis and algal photobioreactors both being capable of producing breathable oxygen and both systems being able to be run with electricity produced from one of several different production options (radioisotope thermoelectric generator, solar photovoltaics, solar thermal, methane combustion, geothermal).
Construction and Layout
An apron ring trench is excavated surrounding the outside edge of the intended shaft and a sulfur concrete ring is 3D printed with the 3D dome printer into the trench to support the vertical shaft sinking machine (VSM) (Figure 3).
Once the VSM is moved into place, the VSM cutting tool begins excavating regolith material from the shaft. Once the minimum starting depth has been excavated, the machine prints the first section of the cylindrical shaft support wall, the first meter of depth being solid, but the remainder of the wall is printed with internal voids which serve to insulate the cylinder, and with channels on the interior wall side for fitting radiant heat tubing. With a final shaft wall thickness of 1 meter, the sulfur concrete, with internal voids, is printed at 0.8 m thick. The cylinder shell is lowered into the shaft as the shaft is excavated, with the cutting tool undermining the shell as the print head continues printing along the top, continuously elongating the shell as it is gradually lowered into the excavation. Horizontal tunnel openings are printed into the shell at the appropriate elevations. Once the cylinder is lowered to its finished depth, the print head is lowered to the bottom of the pit where it prints a 0.8 m thick floor with internal insulation voids and radiant heat tubing channels in its top surface. The VSM machine is then raised and moved to another excavation site and set in motion excavating and printing a new vertical shaft.
The horizontal tunneling machine (Figure 4) can be lowered into the shaft and set to work boring the connecting tunnels. The horizontal tunneling machine 3D prints a similarly constructed 1 m sulfur concrete shoring wall behind it as it moves down the tunnel toward the adjoining vertical shaft.
Once the shaft and connecting tunnels have been bored, and any equipment or material has been removed, the dome printer is used to cap the cylinder with a 3D printed sulfur concrete dome, resulting in what we will refer to as a silo, designating them by their inner diameters.
Airtightness of a finished silo or tunnel is then accomplished through a process of over pressurizing the silo tunnel with atmospheric carbon dioxide and spraying a fine mist of water-soluble acrylic polymer emulsion. The mist is pulled into leaks by the escaping air where it dries in place, building upon itself until the void or leak is plugged. Performing this process up to significant overpressure (121.59 kPa) ensures sealing at nominal pressures (81.2 kPa ideal to a not to exceed pressure of 101.3 kPa).
The interior surfaces can then be lined with a radiant barrier, such as aluminized biaxially-oriented polyethylene terephthalate (BoPET) film. Polyethylene tubing is then installed in the channels for warm water radiant heating circulation. The floor can be covered with 0.2 m thick sintered flat pavers, and the walls can be lined with 0.2 m thick interlocking sintered bricks made from neutralized AAR (red mud)²⁷, machine made to match the wall radius. These will provide internal thermal mass to assist in environmental thermal management, while also serving to protect the airtight barrier from damage, and providing a warm, beautiful interior.
The first constructed shaft would be bored to a diameter of 10 m to a depth of 13 m. This would leave an interior cylindrical space of 12 m in depth and 8 m in diameter covered by a hemispherical dome. Two aluminum truss framed floors are installed, one midway up the cylinder and one at the top of the cylinder. This 8 m silo would be connected to another silo of the same depth, but with a 20 m outer diameter (18 m inner diameter) by two 4 m ID/5 m OD tunnels, one over the other, the first connecting the lower half cylinder, the second the upper half cylinder. The 8 m silo is outfitted to serve as 2 apartments, with the space on the top floor under the dome used for life support equipment and storage. The 18 m silo has 4 other 8 m silos surrounding it, all 5 of them set at 60° intervals around the center. The 18 m silo is outfitted as 2 shared living spaces for the five connecting apartments on the respective levels. The 18 m silo has 6 sets of 2 tunnels, 5 sets connecting to the five 8 m apartment silos, the 6th connecting to another 18 m silo, which is outfitted with a midlevel catwalk and stairs going down to the lower level. Additionally, this silo has no upper floor, and is intended to be planted with an orchard tree and other plants, perhaps with a “living wall”. It will allow the ten residents to access their level of shared living quarters and serve as a transition from private to public space. These transition domes would not only transition residents from their residence levels, but as these domes would be planted with trees and other plants and have automatically controlled natural spectrum lighting (as would most of the public spaces in the settlement) that would simulate a natural day/night cycle of 15 hours of daylight and 9 hours, 37 minutes, 35.244 seconds of darkness, would transition them to an environment that feels like the “outdoors” and assist residents in maintaining a normal and healthy circadian rhythm. The additional 37 minutes, 35.244 seconds of darkness beyond the Earth normal 24-hour day allows the interior “day” to maintain alignment with the actual Martian sol.
The five 8 m apartment silos and one 18 m transition silo surround one 18 m shared living silo. This grouping forms a 10-resident subsector (Figure 5).
The 10-resident subsector is repeated 5 times at 60° intervals around a 46 m silo, which serves as a single level park. The sixth connecting tunnel connects to another 46 m silo, which is outfitted for cafes and market stalls. These five 10-resident subsectors and the one market silo surrounding the 46 m park silo at 60° increments form a 50-resident subsector (Figure 6).
Five 50-resident subsectors and a 138 m farm silo surround a 138 m central park silo to form a 250-resident sector (Figure 7). Also included in the 250-resident sector, are 6 more 46 m market silos surrounding the 138 m park silo at the 30° increments between the 46 m market silos which are part of the 50-resident subsectors. Connected to those six 46 m market silos by longer tunnels radiating outward from the center are six more 46 m silos intended for equipment and tankage.
The culmination of construction and forming the center of the Aeneas settlement, is a 258 m diameter silo, with a 24 m interior depth and covered with a saucer dome (23 m high above top of cylinder (interior)) for a total interior height at the center of 47 m (24 m + 23 m). This is the Campus Martius green, forming a 5.2 ha (52280 m2) park of botanical gardens, lawn, trees, and freshwater pond, complete with aquatic plants, aquatic insects, and fish. This central green, is surrounded by six 138 m silos (interior 24 m depth and divided into 8 floors) at 60° intervals to be used for institutional needs; hospital, classrooms, laboratories, offices, etc. Five of these six institutional silos connect to the five farm silos of the five 250-resident sectors surrounding the Campus Martius/Institutional complex at 60° increments. This provides the settlement with 1250 single resident apartments, 1000 for the permanent residents and 250 rental units for visitors, such as scientists, pleasure tourists, and astronauts. The sixth 138 m institutional silo connects to a 138 m industrial silo which is one of six 138 m industrial silos forming a ring around a central 138 m industrial silo at 60° intervals. Radiating outward from the central 138 m industrial silos are pairs of 46 m industrial silos at the 30° increments between the other 138 m silos on the 60° increments. All but one of these industrial silos have 12 m interior depths and are divided into 3 levels. The outermost 138 m silo in the industrial sector has a 24 m depth and an 18 m tunnel extending eastward and up out of the ground toward the rocket launch and landing pads. This silo is the rocket hanger for rocket storage and maintenance.
In summary, in the finished settlement, there would be 5 silo diameters, identified by their inner diameters of 8 m, 18 m, 46 m, 138 m, and 258 m. There is one 258 m silo with an interior cylinder depth of 24 m and an interior dome height of 23 m forming the Campus Martius central green. There are six 138 m silos with an internal cylinder depth of 24 m surrounding the 258 m silo forming 8 story institutional buildings. There are twenty-nine 138 m silos with an internal cylinder depth of 12 m, 11 of which are outfitted for farming (3 floors each), for a total farming area of 493,585 m2, or 49.4 hectares. The other 18 are for industrial processing, manufacturing, rover hangars, rocket hangar, etc. There are one hundred and twenty-two 46 m silos with an internal cylinder depth of 12 m. Twelve of these are marked for industrial, 55 are for markets. 25 are for parks, and 30 are for equipment/tankage. There are two hundred and fifty 18 m silos with an internal cylinder depth of 12 m. 125 of these are level transition “orchards”. The other 125 are for shared living space. There are six hundred and twenty-five 8 m silos with an internal cylinder depth of 12 m, each with 2 apartments (Figures 8, 9, and 10).
In the early stages of construction, the settlement inhabitants will have to share tighter, more crowded living spaces. Eventually, though, everyone would be provided with a large private apartment. While first impressions may be that the space afforded each person is extreme, it is important to note that there is no habitable “outdoors” on Mars, so it is critical for psychological health to provide habitable spaces that don’t feel confined or claustrophobic. Additionally, while residents would certainly have the freedom to share their space with partners, each adult individual having their own private space available to them would help to eliminate interpersonal conflict. The architecture allows the flexibility that some 5 resident floors could be configured to accommodate families with children.
SUMMARY PLAN
Phase 1–6 Months
Major goals are to survey, assemble equipment, begin excavation, water production, sulfur production
Phase 2–6 months
Major goals are to finish out initial subsectors, move in personnel, begin methane production
Phase 3–48 Months
Major goals are to complete construction, geothermal drilling, set up farming and basic industrialization
Phases 1, 2, & 3 — Total 60 Months
* Shipping cost assumed at $500/kg
Important Note: Equipment weights are based on off-the-shelf equipment largely constructed without regard to weight limitations. While building lighter-weight custom machines would increase the unit costs, there is likely a positive gain in reduced transport costs.
The above summary includes just enough to get the infrastructure in place to feed, clothe, and support 1000 plus people and bootstrap the mining, construction, industrial production, and farming industries within five years. It is reasonable to assume this will cost significantly more than $1.3 billion, but, even at an order of magnitude above this at $10.3 billion, it’s clear that this is a cost-effective path toward permanent human settlement.
As for return on investment, Moon rock samples are currently valued at approximately $50,000 per gram. Even if Mars rocks were valued at half that, it would only take about 412 kg of samples returned to Earth to offset the entire $10.3 billion cost. Meteorites found on Earth sell for between $5000 to $1 million per kilogram. One should expect Mars meteorites, which can be collected all over the surface to have significantly more value. Then, there are gold and platinum group metals such as ruthenium, rhodium, palladium, rhenium, osmium, iridium, and platinum that will likely be isolated during regolith processing. At current Earth prices, and an assumed Earth return cost of $200/kg, all of these represent significant profit margins in ranges from $2600/kg to $87,000/kg.
It costs the International Space Station program about $1.3 million each day for each astronaut aboard. If the Aeneas settlement charged only $200,000/day for room and board at the settlement for visiting astronauts, scientists, and tourists, with a capacity for 250, this alone would represent an income of $18.25 billion per Earth year at full capacity.
SOCIAL ASPECTS OF THE AENEAS SETTLEMENT
To produce a thriving community and culture on Mars will require a comprehensive approach to providing for the needs of its human inhabitants. While an imperfect model, Abraham Maslow’s ‘Hierarchy of Needs’ does provide a basic framework for discussing the physical, emotional, and social needs of human beings. They are, as follows: physiological needs, safety needs, social belonging, esteem, self-actualization, and self-transcendence.
The settlement complex is foremost designed to provide for the immediate physiological needs of the inhabitants; providing safe shelter, with a warm, breathable atmosphere, drinking water, food, and clothing.
The settlement’s social, legal, political, and economic organization are designed to provide its residents with personal, emotional, and financial security, as well as healthcare. Work schedules should be organized to provide all residents with ample amounts of leisure time. The marketplaces, with cafes, bars, restaurants, shops, gyms, theatres, etc. are intended to provide residents with opportunities for entertainment, socializing, pursuing hobbies, exercising, and playing sports (it isn’t difficult to imagine people having a lot of fun adapting Earth sports to Martian gravity).
Settlement recruitment would have to consider numerous factors. Moving to Mars is a long, difficult, and potentially dangerous trip. The orbital mechanics of the Earth-Mars Hohmann transfer orbit necessitate that work contracts would be a minimum of 26 Earth months. The community will require experts in mining, construction, industrial processes, robotics, energy production, chemical engineering, metallurgy, manufacturing, horticulture, life support systems, doctors, dentists, massage therapists, physical trainers, chefs, waiters, brew masters, bartenders, musicians, artisans, etc. Potential community members would be chosen from applicants based on their experience, expertise, and emotional intelligence, as well as mental health and stability, Those chosen to become members of the settlement, would have the option of renewing their contracts, or returning to Earth, avoiding the possibility that anyone feel permanently trapped.
At the small community size of 1000 people, and as intimacy and sex are as vital to human emotional health as water, food, and sleep are to physical health, preference should be given to partnered couples²⁸,²⁹.
It’s critical to the success of the settlement that a culture of mutual respect be established and maintained. To this end, it would be recommended that founding leadership be composed of experienced leaders, who have demonstrated a history of mentorship and an adherence to the philosophy of servant leadership³⁰.
CONCLUSION
This paper started by saying that a settlement of a thousand people doesn’t pop into existence; that it would grow from a smaller settlement into a thousand people and if successful would grow beyond that thousand. So far, it has been discussed how to establish it and grow it to that moment in time where the population reaches that one thousand, but what of its future? What lies ahead for Aeneas?
One can envision a similar pattern of development continuing around the original Aeneas complex. The boreholes, tunnels, and subsurface excavations would become wider, deeper, longer, and more sophisticated as the settlement grows, continues industrializing, and develops new tools and construction techniques. Eventually, it would grow into a large city with enormously large diameter boreholes a kilometer deep ringed with apartments and balconies, like inside-out skyscrapers plunged into the ground, each housing thousands; open space caverns dwarfing the original Campus Martius central green. One can imagine a future city of millions, with underground open spaces of forests and lakes, people walking, riding bicycles, and using a tube transport system to get around.
As this city grows, the original Aeneas complex at the historic center of the city would be transformed into the first Martian University; the original apartments becoming dormitories; the original Campus Martius now, quite literally, a campus green.
In May 2003, Dr. Richard E. Smalley presented his ‘Humanity’s Top Ten Problems for the Next 50 Years’. He prioritized them in a top down hierarchy: Energy, Water, Food, Environment, Poverty, Terrorism and War, Disease, Education, Democracy, and Population. The idea being that as the problems at the top of the list, starting with energy, are solved, the issues below become easier to resolve. These are the challenges for humanity on Earth.
The Aeneas settlement won’t be a utopia. It will have significant challenges, but by providing the freedom, security, opportunity, and lifestyles that people aspire to achieve; by focusing on creating a settlement with abundant energy, water, and food; a pleasing living environment; opportunities for education, art, and entertainment; an economy where each individual is provided the opportunity to not only contribute to the advancement of their community, but to the establishment and advancement of human civilization beyond Earth; the political and economic instability, inequality, terrorism, war, disease, and overpopulation of Earth will provide the impetus for human migration to Mars.
POSTSCRIPT
A note about the names, Aeneas and Campus Martius. Aeneas (/ɪˈniːəs/) is a Trojan hero of Greco-Roman mythology, and is featured in Virgil’s epic poem, the Aeneid, where he is portrayed as having fled to Italy after the fall of Troy to become a progenitor of the Romans. Aeneas is believed to have founded the settlement that would later become Rome, several generations later, when Romulus laid out its fortifications and became its first king. The Romans, in turn, revered Mars, the god of military power (viewed as a way of securing the peace, the Pax Romana) and the guardian of agricultural. The Campus Martius (/ˈkampəs/ /ˈmär-sh(ē-)əs-/), or Field of Mars, was about a 2 square km publicly owned area of ancient Rome.
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