Journal of Cosmology, 2010, Vol 12, xxxxx.
JournalofCosmology.com, January, 2011
The Mars Homestead For An Early Mars Scientific Settlement Bruce Mackenzie, Ph.D.1, Georgi Petrov, Bart Leahy, and Anthony Blair
1Mars Foundation, 102 Sanborn Ln, Reading, MA 01867-1009, USA
The Mars Homestead™ is a major project of The Mars Foundation™. The goal is to develop a detailed plan for a permanent Mars Scientific Settlement similar to the NASA Design Reference Mission. Emphasis is placed on achieving success as early as possible, and maximizing the use of local resources. Two variations of the master plan are considered. The first is a hillside linear layout. The second, still under development, is a redesign that places the same program in an open plain site. The first crew on Mars would delay major scientific studies to concentrate on producing building materials, habitat construction and food. After the initial base is complete, construction would continue, allowing an additional dozen scientists to arrive every two years, bringing only their personal effects and specialized equipment. The cost of sending the manufacturing equipment can be recouped by eliminating the cost to return later crews to Earth after short rotations. Preliminary estimates show that the launch cost of a permanent scientific base for a dozen scientists (and growing) would be the same as the “Design Reference Mission” for three round-trip missions of six people each, while avoiding the significant risks of multiple return trips to Earth. Given the cyclical history of aerospace funding, this plan to establish an early permanent scientific base and grow it into a vigorous settlement may advance the settlement of space by an entire generation. Participation is welcome to everyone, including contributions by non-aerospace engineers.
Key Words: Mars, Space Settlement, Space Colonization, in-situ resource, construction, life in extreme environments, Astrobiology, space radiation environment
The Mars Homestead Project is the key endeavor of the Mars Foundation™, a non-profit, 501(c)(3) organization dedicated to establishing permanent, thriving settlements beyond Earth, starting with Mars. The goal of the project is to develop a reference design for the first permanent Mars settlement built primarily from local resources. This early, permanent base can support scientific investigations more cost effectively and safely than a series of round-trip missions. Likewise, instead of focusing on the application of a single technology, the project takes a broad view of all the necessary structures and materials for the constructing the initial 12-person phase of a growing settlement.
Preliminary estimates indicate that the delivered mass to establish a permanent scientific base for the initial dozen scientists would total about 250 tons. This is approximately the same mass as NASA’s Design Reference Mission (DRM), but is more cost effective. The DRM proposes three round-trip missions of six people each, totaling less than 24 person-years of time on the surface over a decade. Our alternative delays scientific studies, though it supports 12 person-years of effort each year, quickly growing to 24, 36, and more person-years every other year.
This cost savings is possible by eliminating the need for most return flights, their fuel manufacture, and consumables. Given the cyclical history of aerospace funding, it is critical to establish a reasonably self-sufficient base before enthusiasm and funding wanes. Prior to the crew’s arrival, pre-positioned habitats, food, and equipment will be sent to Mars to produce: power, breathing gases (oxygen (O2), nitrogen (N2), and argon (Ar), water, fuel, and possibly industrial materials. The initial crew of four would concentrate on establishing long-term life support equipment, and would set up automated equipment to produce building materials, such as fiberglass, polymers, ceramics, glass and brick. Assuming the life-support system is reliable, they would then be joined by two more crews, bringing the total to 12 people. After full production equipment is in service, they would assemble additional manufacturing modules, greenhouses, labs, and living quarters built from local materials. Construction would continue after the crew moves to the permanent living space, allowing additional crews to arrive every two years. The new arrivals need only bring their personal effects and specialized equipment, allowing the scientific base to grow at about one-third the cost of round-trip missions.
2. Hillside Settlement
A detailed master plan for a “Hillside Settlement” has already been established. It would include living quarters, workshops, greenhouses, maintenance facilities, waste processing, refining, manufacturing, and other areas needed to live and work (Figure 1). Once the team establishes residency in their completed quarters, they will resume construction of additional facilities to hold another dozen persons, mainly scientists who will arrive every subsequence two years. As progress continues, the base will grow into a permanent manufacturing settlement, producing equipment for additional scientific outposts and other permanent settlements.
Figure 1. Aerial View Of The Hillside Settlement, At The Stage When First Occupied By 12 People.2.1 Plains Settlement Realizing that a convenient hillside might not be available near the desired settlement location, the team is now undertaking a new study to adapt the same program to an open plain area, or most any site which is flat enough to be a good spacecraft landing site. One of the primary differences between the hillside and the plains settlements is the lack of radiation shielding provided by the hillside. Preliminary images are shown in Figure 2.
Materials The plains settlement could be located anywhere on Mars where there are available water (as ice in the soil) and silicates suitable for the manufacture of fiberglass. If water-ice is not available, it could extracted from the air, but at an unreasonable cost. If fiberglass is difficult to manufacture from the local soils, alternate materials are possible, including: polymers such as polyester and nylon, spun basalt, recycled aluminum, iron and steel from the iron carbonyl process. As many materials as possible would be produced locally using general purpose equipment sent from Earth.
Interior furnishings could be constructed of locally produced fiberglass, plastic, pressboard panels, extra piping, parachute cloth, and masonry. Once extra greenhouse space is available, bamboo, paper, soybean oil, cloth, and other plant products grown on site could provide additional raw materials for furnishings.
Cylindrical Habitats Materials such as fiberglass and polyester would be used for fabricating pressurized horizontal cylindrical habitats. They are arbitrarily dimensioned to be 5 meters in diameter and 20 or 30 meters long. This provides significant width of the floor, and space below the floor and above a ceiling for equipment and storage. Connection rings are 2.5 meters in diameter. Additional spherical connection nodes allow 4 cylindrical modules to be connected together. This avoids the structural problems of connecting to the side of a cylindrical module.
Large inflatable ‘assembly tents’ house bulky fabrication and fiberglass spinning equipment, and provide valuable factory floor space (left-foreground in Figure 2). Half-sized modules would be spun on a fiber glass lathe, and then joined together in a separate ‘finishing tent’, which also serves as an air-lock (middle-foreground in Figure 2).
Figure 2. Aerial View of the Plains Settlement, With Shielding Canopy Cut BackRadiation Shielding Canopy Sintered bricks would be used for foundations supports and load bearing columns. The columns support an overhead canopy holding regolith for radiation sheilding. Protection against cosmic rays can be improved at a later date by adding a top layer of any material with lightweight atomic nuclei, such as bags of water-ice, waste plant material, or any carbon-based compound; when such materials are available. Gaps below the modules and between the modules and canopy are critical for external maintenance and cooling. This design of raised modules can be adapted for a polar settlement built on permafrost, provided the foundations are kept cool by the wind. In Figure 2, the canopy is partially cut back to show the horizontal cylindrical habitats and spherical connection modules.
A possible alternative is to construct a box frame around the cylindrical module (not shown). This allows more assembly to be performed indoors. The modules may be stacked when the settlement is large enough to justify two story structures. Overhead trays constructed indoors as part of the box frame would later be covered with regolith for radiation shielding.
Other Features To allow extra light and overhead radiation shielding, greenhouses would be lit through side windows from external gimbaled mirrors (shown and described later in this paper). The settlement primarily utilizes nuclear power (not shown), not just for electrical generation, but also for industrial heat, such as manufacture of polymers, preheating during sintering of ceramics, manufacture of fuels, and breathable air.
Note the ‘observation deck’ rising above the canopy in the background of Figure 2. It has water tanks in the ceiling and awning for radiation shielding. The observation deck nominally serves as a supervisory station for construction of settlement and vehicles, much like an airport control tower, but with ubiquitous remote cameras that is not really needed. The real justification for it is psychological; it provides a place with a spacious view for meals, small meetings, private relaxation, and a sense of accomplishment, which are critical for settlers who will be on Mars for many years.
3. Martian Technologies / Social Considerations
Any task as massive and difficult as exploring and settling Mars requires advance planning, development, and other efforts to literally and figuratively “get off the ground.” These steps include feasibility studies, prototype projects, operational and environmental research, identifying funding sources, hardware development, and preliminary exploration. The Foundation has already taken the first step by developing a feasibility study and—like NASA, though with a different emphasis—a design reference mission. The Mars Homestead Project—our feasibility study—began by identifying the basic mission of a Mars settlement and the primary challenges involved in building such a habitat.
3.1 Marian Settlement Challenges The Mars Homestead Project began with a simple operational premise: establish a permanent base on Mars to perform high-value scientific and engineering research and then to grow the outpost into a larger, permanent settlement. This vision includes:
Testing manufacturing methods to use Mars resources.
Searching for past and present life on Mars.
Conducting basic science research to gain new knowledge about the history of the solar system.
Performing scientific research to use Martian resources to support human life.Maximum Flexibility vs. Mass Production The first Mars settlement will face slow and limited communications with Earth. This will require a great deal of self-sufficiency in developing tools and structures. This situation will require flexible small-scale manufacturing and creative engineers skilled machinists capable of both high-tech and low-tech manufacturing—the equivalent of medieval blacksmiths.
Worker Productivity Because the first crews to Mars will most likely be small—growing from 4 to 8 to 12 people initially—the crew must, of necessity comprise individuals capable of multitasking in a variety of disciplines. This would include civil engineering, life support systems, medical science, botany, microbiology, mechanical engineering, laboratory science, and, especially, simple mechanical maintenance. Such multitasking necessarily implies high worker productivity and proficiency across multiple disciplines. Illnesses or deaths will leave the crew short of vital skills and will necessarily result in emotional and social strain among the crew, though obviously they will have support from experts on Earth. This support would include redesigning equipment on Earth, and transmitting the new designs to be manufactured on Mars.
Limited Earth-Mars Transportation Many high-technology items will need to be flown to Mars from Earth, such as nuclear reactors and specialized laboratory equipment. The settlers must be able to manufacture low-technology, high-mass materials (e.g. bricks, Fiberglas, or iron) on Mars. We assume no radical advances in propulsion in the near future, and that any incremental advances will be used to reduce the cost rather than to increase the mass delivered to Mars. In addition, the orbital mechanics of Earth and Mars dictate that flights only occur during the launch windows every two and one-seventh Earth years. Such potential delays mean that several fundamental requirements must be met:
Earth-Mars cargo support flights must be restricted to high-cost, high-technology equipment.
Mission-critical equipment sent from Earth must be highly reliable.
The crew must have the capability to manufacture simple but necessary materials or equipment on-site.Unknowns While any exploration or settlement crew is unlikely to encounter dragons or hostile natives, they will still have to cope with “unknown unknowns” related to interactions between people or equipment and the Martian environment, including the thin atmosphere, soil chemistry, low gravity, sub-arctic temperatures, radiation, low magnetic fields, microbial-natives, dust, and weather. Such unknowns will impact settlers’ efforts to adapt Earth-based mining, refining, and manufacturing to Mars, the safety and reliability of equipment, and the overall cost of establishing the settlement.
In addition to the unknowns, one advantage of a one-way long term mission is the possibility of discovering native Martian pathogens. To help alleviate the public fear of transmission of Martians germs to Earth a one-way mission would serve as a method of temporary quarantine to determine if such pathogens pose a serious risk to humans. In the likelihood that such pathogens exist, the initial crew would have to stay on Mars indefinitely.
4. Martian Engineering Constraints/Solutions
Mars presents any future builders with a variety of serious challenges and constraints, from near-vacuum atmospheric conditions to sub-zero temperatures lower than anything experienced in Antarctica.
Table 1 below summarizes some of the highlighted differences between the two planets. Given these extremes and constraints, it is important for any future expedition to identify and budget for the resources it will have available upon arrival. To build a permanent habitation, a settlement expedition will have the tools and equipment aboard the arriving spacecraft (most likely several vehicles, some arriving before the crew), local materials (meaning the land, water, and atmospheric components of the planet Mars), and the human beings and robots making up the crew.
Table 1. Planetary Comparisons Between Earth and Mars.
Earth Mars Distance from Sun 150 million km 225 million km Diameter 12,756 km 6,786 km Axial Tilt 23.5° 25° Length of Year 365.25 Earth Days 687 Earth Days Length of Days 24 hours 24 hours 37 minutes Gravity 1 g .38 g Temperature Range -88°C to 58°C -127°C to 17°C Atmospheric Pressure 1013 mb (avg.) 7 mb (avg.) Atmospheric Gases 78% N2, 21% O2 95% CO2 Polar Ice Caps Water Ice Water Ice and Dry Ice (CO2) Highest Point Mount Everest – 8.848 km above sea level Olympus Mons –27 km above Martian avg. Lowest Point Marianas Trench – 11.022 km below sea level Hellas Basin – 4 km below Martian average Imported ResourcesFor the purposes of the original study, the team estimated a total arrival mass of 250 metric tons (tonnes) of cargo. Within this mass would be:
Crew – Increasing crew size from 4 to 8 to 12 people, to make on-site decisions, set up and test and repair equipment, and perform many non-repetitive assembly tasks. Having people on Mars is the whole purpose for going.Robotic Equipment / Robots – Both general purpose and dedicated robotic systems for the majority of repetitive tasks.
Food and Shelter – Temporary living quarters, life support, and food necessary to support that labor until a permanent habitat is established.
Power System – including three nuclear reactors providing industrial heating and up to 400 kilowatts (kW) of electrical power, and the cables and other components needed to distribute the power throughout the settlement.
Construction Equipment – such as tractors, dump trailers, drag lines, sifting equipment, “fork lifts”, etc. Initial Mining, Refining, and Manufacturing Equipment—to make gases, chemicals, metals, plastics, ceramics, masonry, glass out of the local atmospheric and regolith materials at hand. In some cases, the manufacturing equipment can be bootstrapped to make more capable manufacturing equipment once on-site.
High-Tech / Low-Mass Items – Any items that would be difficult to manufacture initially on Mars, such as sensors, computers, cameras, radios, other electronics, bearings, precision tools, small valves, medicines, medical devices, and small high-precision mechanical devices.
Scavenged Equipment – Anything that can be re-used from the Mars landing craft, whether designed to be reused in advance, or cannibalized after the fact. These include avionics, computers, control systems, wiring, actuators, sensors, nylon from parachutes, sheet metals, tanks, piping, etc.
Local Resources The “mining” equipment for the first Mars settlement must also include air miners that will ingest material from the Martian atmosphere, which consists of 95.3% carbon dioxide (CO2), 2.7% N2, 1.6% Ar, 0.15% O2, and 0.03% water vapor (H2O) at a pressure around 7 millibars (mbar). After collecting this material, the air miners will use standard, existing chemical processes to create oxygen, habitat buffer gases (N2/Ar mix), methane (CH4), and hydrogen (H2) fuel, longer-chain hydrocarbons, and plastics (including epoxy). Depending on the amount of water available in the local ground or atmosphere, Martian water also could used to nourish plants in the settlement’s greenhouse. In addition to air mining, a similar process will be performed with available local resources in the Martian rock and regolith through ore beneficiation, that is, the crushing and separating ore into valuable substances or waste by any of a variety of techniques, (Petrov, 2004).4. Construction
Mining is only the first step in building the settlement. Once raw materials are obtained, the settlement structure can be built. Due to the extreme cost of importing materials and equipment, relying on habitats brought entirely from Earth is an unsustainable strategy, unless there are revolutionary advances in transportation or manufacturing.
The Mars Homestead Project plan provides efficiency in transportation, infrastructure, safety, and ease of expansion. As a two-avenue structure, the “Linear City” of the Mars settlement will have separately pressurized segments with inflatable modules or regolith-supported masonry to keep the utilities, such as air, water, and power distribution following the “streets” of the city in sub-floor panels beneath the floors.
The team agreed that excavating to build the settlement was much simpler than tunneling for the reasons described in Table 2, below.
Table 2. Comparative Advantages Of Excavation Vs. Tunneling.
Excavation and Covering Tunneling Excavation is optional, as long as firm soil is reached Excavation and covering necessary for entrance area and extraction of raw materials Can be located in most any terrain Prefer a hill or vertical entrance to reach solid rock Building the cover may be done accurately and safely Suitable for many soil types, use sintering for needed strength Relies on strength of rocks above Can fragment rock and permafrost using chemical explosives Requires cutting of solid rock Lower precision requirementThe estimated work will require 20 man-weeks of work to excavate, based on conservative estimates. Small domes and vaults can be built in two days on Earth. As a conservative estimate, the project team assumed that it would take three times as long to do the work on Mars, including arches and walls. Each unit would take two to four man-weeks to complete. The large vaults are twice as big, so they would most likely take eight man-weeks each. The large dome will require special construction methods, so the team assumed an assembly time of 50 man-weeks. The total amount of time required to perform masonry work would be 298 man-weeks.
Given the design of the team’s settlement, summarized in Table 3, and the constraints inherent in building on Mars, we estimated the total construction time to break down in Table 4.
Given an available building staff of four individuals, the entire settlement construction effort would take 560 man-weeks, with an additional 182 man-weeks for safety and helping the engineers install inflatable modules, airlocks, doors, windows, skylights.
Table 3. Summary Of Masonry Structures
Table 4. Construction Time
As the land is being leveled for development, the settlers will use the excavated regolith (dirt) as raw material to make brick, glass, and metal. The emphasis of this settlement will be on using local materials as much as possible to complete construction of a habitat. Continuing to rely on habitats brought from Earth is an unsustainable strategy. Therefore, settlers must maximize their use of Martian materials and simple, well understood, and tested building techniques.
Antique as well as modern methods of construction would be used to build the first Mars settlement. Ancient methods of construction would include masonry work, while modern methods would rigid cylinders made by winding fiberglass; sheet metal would be used where practical; and inflatable structures with rigid internal floors and partitions could be included as well.
The masonry structures would be based on bricks sintered from Martian regolith, reinforced with glass fibers if needed. If that is not practical, the masonry blocks could be glass blocks, fused basalt, or cut stone. Brick manufacturing would require some 2,200 cubic meters of material, which can be obtained from the regolith excavated from the hill. Heat from the nuclear reactors can pre-heat the kiln needed to fire the brick, with the final temperature reached by electric heat or burning chemical fuel produced from the CO2 atmosphere. There will be two kilns of 1.5 cubic meters’ capacity each, with a firing of time 8 hours. Given two batches per day and 6 cubic meters of brick being processed per day, it will take 370 days to make all of the brick required to build the settlement. Given the simplicity of this automated process, human intervention will be required only to maintain the equipment. A total of 20 man-weeks will be required for brick manufacturing. After the bricks are manufactured, the team must start assembling their new home. This will require a variety of different-sized vaults to achieve the size and comfort level required by the inhabitants.
5. Better Martian Living Spaces
Given the known and potential unknown constraints on future human explorers, the study members believed that it was not enough to build a survivable Martian habitat; priority was given to building pleasant, permanent habitations on or under the Martian surface. As noted earlier, the settlers will use the temporary shelter of their arriving spacecraft until construction of the first phase is completed. The sooner settlers are able to establish a homelike environment for themselves, the sooner we can save costs and risks of frequent return flights. Also, a permanent base can easily support scientific exploration, while leading to the true goal of settlement for large numbers of people, with animals and plants.
5.1 Vision – The Hillside Settlement The Mars Homestead Project team designed a partially underground, partially exposed facility built largely from local materials. Using a combination of imported and local resources, the Hillside Settlement will be approximately 90% self-sufficient by mass and will provide the settlers with the industrial capabilities they need to explore and settle the frontier.
The team selected Candor Chasma at reference coordinates 69.95W x 6.36S x -4.4km as the site for the Hillside Settlement. This site is part of the Valles Marineris canyon complex and has been photographed by Mars Global Surveyor. It consists of a number of mesas suitable for providing shelter as well as room for expansion. The site was chosen primarily for its proximity to several dry riverbed-like features. It is also reasonably close to Pavonis Mons, Olympus Mons, and other features of geologic interest. Site selection and response to the site are key design issues for the first settlement. There are a large number of engineering and logistical challenges to be considered in placing the settlement, (James 1998). The settlement must be located in proximity to geologically varied regions of scientific interest. There must be easily accessible in-situ resources. Low elevation is important to take advantage of higher atmospheric pressure, which aids both in harvesting gases from the atmosphere and landing with parachutes. Locations near the equator offer the highest solar intensity for crops, and access to and from any orbit.
There are many architectural and urbanistic issues to consider as well, (Alexander, 1977). The first permanent habitat will be our first cut into the new frontier. This is a very important step that will have an effect on the future development of the planet. A transplant of a pattern from the homeland in a model such as the “Law of the Indies”, in which the Spanish crown dictated the masterplan of every city in the New World, will not work. There simply won’t be the resources available to impose a predetermined plan that doesn’t account for local conditions. The other extreme of a completely unplanned and pragmatic approach like the one taken by North American settlers is also unrealistic. The base must react to the site within a set of guiding rules.
The site must also provide a real and perceived sense of protection. On Earth, the location of a new settlement has traditionally been dominated by considerations for defense. On Mars there are no natives to defend against, but the need for a psychological sense of protection against a hostile environment is still real. Finally, any settlement needs a symbol that the residents can identify with, a landmark that identifies the structure as home, or a sacred place that will symbolize the founding of the community. It should be recognized that eventually the site of the first settlement will become a place of veneration and pilgrimage.
In the years to come, the Foundation will continue to gather more accurate and detailed information about Mars and almost certainly will reach a much more informed decision about the final site. For the purpose of this project, a site was chosen based on the best available information as of autumn 2004.
Candor Chasma A group of mesas in the middle of Candor Chasma fulfill many of the requirements for a successful site. Candor Chasma is one of the northern branches of Valles Marineris (Figure 3). The elevation of the floor of the canyon is almost 4,800 meters below the planetary mean, offering relatively high atmospheric pressure. The walls of the canyon are about eight kilometers above the base. The panorama of the cliffs and valleys will present a beautiful view for the first settlement. Additionally the mesas themselves present an interesting site, giving the settlement a view in the close range as well. There are relatively flat areas to the north and south of the mesas that can serve as landing areas, where the flight paths to and from orbit will not overfly the settlement.
Figure 3. Candor Chasma, The Hillside Settlement Reference Location Shown On An Elevation Map Of Mars
Figure 4. Initial, “Tuna-Can” Style Temporary Habitats Brought From Earth, Greenhouse, Ascent Craft, And Water Well To Tap Permafrost.
As seen in the site plan, Figure 5, the Hillside Settlement reference design is quite extensive. It provides habitation for 12 people and covers 800 square meters, with greenhouses, fuel, nuclear plants, and manufacturing facilities located outside. Private living spaces, labs, and common areas are situated inside the mesa, with some of the rooms providing views of the outside.
Entrance The main entrance is composed of two pressurized modules: the main entry and a garage. The main entry module consists of two airlocks with multiple egress options. One of the airlocks will provide direct access to the Martian surface for daily exterior activities, such as construction and repair work. The other airlock will be a docking port for rovers, (Petrov, 2005).
Figure 5. Hillside Settlement Reference Design—Site Plan.Social Spaces The settlement will include areas for the entire group to gather in one place. These spaces are arranged along the infrastructure, with vegetation mediating the spaces between humans in a “Chinese garden” fashion. The human activities are located in the center with the trees surrounding them on two sides. This is where the community comes together on a daily basis (Figure 6 and later Figure 9). The space includes the communal kitchen and dining areas. The two bays above the dining area are covered with two-story high barrel vaults marking this as a special subspace of the segment. The second level includes balconies, catwalks, public work spaces, and also spaces for exercise and entertainment. Figure 6 below depicts how vegetation would be used in the floor plans.
Figure 6. Close Up Schematic of Settlement Social Spaces.The Greenhouse The greenhouses are the largest modules of the settlement and are situated on the flat land extending away from the mesa. The greenhouses are built with redundancy in mind: if one unit fails, demand can be covered by adjacent units. Each module has the complete ability to recycle water, air, and nutrients. The waste handling and water purification units are in the greenhouses and their adjacent modules. Note that 100% recycling is not required, since gases, water, and minerals can be extracted from Mars air and soil. Two greenhouses are transparent to take advantage of natural sunlight, and are supplemented with artificial light as needed. The other two greenhouses are opaque, covered with regolith, and artificially lit (Figure 7).
Figure 7. Concept Design For Gravel Bed Hydroponic Greenhouse Interior.Growing food on Mars would be much different from Earth. One extreme difference is the amount of ultraviolet (UV) radiation that reaches the surface of the planet. This is a major problem when trying to grow Martian-based crops. One possible solution would be to create crop plants that are UV tolerant. This would decrease the need for protective UV coating on Martian green houses.
Other photosynthetic producers on Earth have a natural way of resisting UV radiation with no cost to the productivity of photosynthesis. Microalgal groups create mycosporine-like amino acids (MAA) that absorb UV, (Karentz, 1991). This process is very prevalent in the Antarctic regions, where the ozone hole forms annually. The introduction of MAA algae genes into crops might help Martian agro-productivity.
The crops include a variety of vegetables and grains, as well as some non-edible plants grown for their fibers or usefulness in making particle board. Initially, crops will be grown hydroponically, in trays made from local fiberglass or ceramic pots, and filled with gravel. Later, we hope to grow plants in native soils after leaching harmful minerals as needed and adding organic material. Additionally, since some residents plan to spend a considerable number of year, or the rest of their lives on Mars, the greenhouses are deliberately designed for long sight lines, walking, jogging, or for solitude after work hours.
Side-Lit Greenhouse One possible design for a passively heated and cooled greenhouse is shown in Figure 8. It is designed to use minimal electrical energy for heating and cooling and ventilation, especially during emergency conditions.
Figure 8. Side-Lit Greenhouse, With Radiation Shield Canopy.Sunlight is concentrated by moveable mirrors at the left side, and focusing them through side windows. An overhead scaffold holds radiation shielding material (regolith, ice, or any other material) to retain heat. Air ducts and passageways allow warm air convection to other habitat modules to the right, such as workshops, the kitchen, etc. Not shown are curtains which can be closed at night to retain heat when needed, or opened to allow wind cooling, with chimneys for additional convective cooling if needed.
In the event that an extreme emergency makes much of the base unusable and/or limits electrical power, the crew can retreat to these greenhouses and adjacent workshops and kitchen. There they have all the essentials to live and can repair whatever equipment may have caused the problem. This ‘Side Lit” greenhouse was not incorporated in the Hillside Settlement design, but is being used in the follow-on designs.
Using Vegetation as a Fundamental Aspect of Settlement Life Internal vegetation will be an integral part of the Mars settlement’s social structure and sustainability, as it will be used as a symbol, life support component, mediator of exterior views, green belt for breaking up social spaces, and overall mediator of social life, (Alexander, 1997).
As a symbol, vegetation will hold a special place immediately between the main entrance and the formal meeting space, as the settlers will plant trees on arrival. These plants will symbolize hope and the permanence of the settlement. The trees will grow as the settlement expands, and when people arrive from Earth, the first thing they will see as they enter is the grove of trees. These trees could also provide an occasional fruit or nut.
As a life support component, plant-rated greenhouses will optimize atmosphere, light, structure, and safety for specially designed plants. The farmers will plant seedlings and harvest the crops from inside a pressurized area with the aid of robots.
As a mediator of views within the settlement structure, plants will be placed in front of any windows to the outside, allowing settlers to look at the red of Mars through the soothing green of Earth vegetation. This added “touch of home” aids in settler psychology and stability. Additionally, every private suite has a small garden area in front of its window, and connector segments will terminate with small gardens and a window onto Mars. As a green belt, vegetation will separate heavily traveled areas from work spaces.
As a mediator of social life, plant life can be located either at the center of, or on the periphery of, social spaces. Where plants are in the center, the various social spaces are arranged around the periphery and every social space has views through the vegetation to the other social spaces. Those space with plants around the edge are like a “clearing in the woods” or a “Chinese garden”, where the social space is surrounded and protected by trees. The edges of the space will be hidden, thus obscuring the limited size of the space. Finally, the lifecycle of the vegetation will provide seasonal visual changes in the living space, (Alexander, 1977).
Other Humanizing Features In addition to plants, the overall settlement structure will be laid out with human psychology in mind, as it will feature social “spaces” to cover the entire range of human experiences, from the individual to couples to informal subgroups, sub-team meetings, and the entire community.
Figure 9, an image by Phil Smith, depicts large, open, multi-story masonry structures that are buried at the edge of the hillside. Natural sunlight is directed into this area from light shafts above (Figure 10). A Mars settler leans on the bamboo rail and takes in the view, overlooking lush green spaces.
Figure 9. Interior Of Two Story Common Area.As life in our urban society has shown, artificial lighting is not enough to meet human needs. Therefore, the domes where vegetation is housed will have shafts that reach to the surface, as shown in Figure 10, below. There, light is collected by lenses and brought down to an opening in the top of the dome, where it is spread out again by another lens. This segment encloses a total volume of 1,530 cubic meters and has 125 square meters of floor space.
Rigid cylinders are used in the flat, open areas away from the hillside. The smaller, standard-size rigid modules would be wound fiberglass, constructed inside an inflatable construction tent. The larger ones would be sheet metal welded or riveted on-site, outdoors. Most would be covered with at least 1 meter of regolith (dirt). These modules are at the left of the cut-away Figure 10, and top of the site plan, Figure 5. They include: greenhouses, nuclear power ‘balance of plant’ in purple, and some manufacturing spaces.
Buried masonry vaults and domes are used for much of the living space. We excavate into the hillside in the loose talus slope, and build the vaults there. To hold the internal pressure, several meters of regolith (overburden) must be placed over them. Obviously, the masonry must be strong enough to hold the weight of the overburdened, and have buttresses shaped to hold the weight whether they are pressurized or depressurized. To keep the air from leaking, the bricks are glazed and caulked on the inside. In addition, alternating layers of sand and vapor barrier are placed outside the masonry to collect air which does leak, and route it back into the air processing equipment to be recovered. These modules are at the bottom of the site plan, Figure 5, shown with thick walls, also in Figure 5 and at the right of the cut-away, Figure 10. They include the: two-story public space, labs, kitchen, dining area, (Mackenzie, 1987).
Figure 10. Cut-Away View, Greenhouse On Left, Shallow Masonry Covering Inflatable In Center, Deeply Buried Two Story Masonry On Right, Light Collectors In Upper Right.Pressurized Construction Figure 10 also illustrates a good comparison of different construction techniques to handle the internal air pressure.
Masonry is used over inflatable structures at the edge of the hillside, to transition from the deeply buried masonry vaults to the open area. These are simple inflatable cylinders made from thinner fiberglass or cloth or thin sheet metal. They are used inside masonry vaults for protection. The masonry also holds the hillside back and provides radiation protection. These modules are at the middle of the site plan, Figure 5, shown as thick walls with rounded lines inside them, also at the middle of the cut-away, Figure 10. They include: private suites, waste treatment, greenhouse support, main entry, suit room, rover garage, and some manufacturing spaces.
6. Joining Mars Homestead Project
The Mars Homestead Project can use volunteer help as well as material donations and financial assistance to keep projects like this viable. The Mars Foundation manages a number of task forces and sub-projects to continue and further articulate its Earth-based studies for future Martian settlement.
6.1 Prototype Projects The Foundation plans to sponsor prototype projects, which are small projects suitable for local groups, students, university classes. These projects would design or select equipment to facilitate a self-sustaining settlement on Mars. Such activities could include: Other activities include greenhouse experiments, outfitting a single module of the proposed settlement, or developing small robotic projects.
Mars Homestead and Mars Foundation are trademarks of the Mars Institute incorporated in Massachusetts, USA. We can be reached by email at Info@MarsHome.org or on the Internet at http://www.MarsHome.org.
The Mars Foundation’s Homestead Project, compared to round-trip missions, is a cost-effective, human-friendly method of settling Mars. With a one-way mission we avoid multiple risks and the costs of return flights. Refining equipment from Earth produces fiberglass, masonry, plastics, and metal construction materials. Semi-automated manufacturing equipment assembles the habitats, laboratories, and greenhouses for permanent use. Thus, we can afford to build a permanent, growing base to both support scientific study, and immediately start settlement. This would cost about the same as three round-trip missions, such as the NASA Design Reference Missions (DRM). The Foundation strongly encourages interested readers of the Journal of Cosmology to join the Mars Homestead project, or suggest complementary projects.
ACKNOWLEDGMENTS: Numerous people helped with the technology and other aspects of the Mars Homestead program, and the specific Hillside Settlement design. They including: Adam Burch, April Andreas, Bruce Mackenzie, Damon Ellender, Frank Crossman, Gary Fisher, Georgi Petrov, Ian O’Neill, Inka Hublitz, Jaime Dorsey, James Burk, James Ghoston, K. Manjunatha, Mike Delaney, Randall Severy, Richard Sylvan, Robert Dyck, Susan Martin, William Johns. Special thanks to Georgi Petrov, Phil Smith, Bryan Versteeg, Adam Burch, and NASA for the images.
REFERENCESAlexander, C. (1977). A Pattern Language. Oxford University Press.
James G., Chamitoff, G., Barker, D. (1998). Resource Utilization and Site Selection for a Self-Sufficient Martian Outpost.” NASA/TM-98-206538.
Karentz, D., McEuen S., Land, M., Dunlap, W. (1991). Survey of mycosporine-like amino acid compounds in Antarctic marine organisms: Potential protection from ultraviolet exposure, Marine Biology, ISBN 0025-3162
Mackenzie, B. (1987). Building Mars Habitats Using Local Material, pg 575 in The Case for Mars III: Strategies for Exploration. Stoker, Carol ed., American Astronautical Society: Science and Technology Series v74.
Petrov, G. (2004). A Permanent Settlement on Mars: The First Cut in the Land of a New Frontier. Master of Architecture Thesis, MIT .
Petrov, G. I., Mackenzie B., Homnick M., and Palaia J. (2005). A Permanent Settlement on Mars: The Architecture of the Mars Homestead Project. Society of Automotive Engineers (SAE) International.
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