Pioneer House Building

Version 1.1

By IonMars

Last edited September 10, 2014

[Note: Version 1.1 utilizes epoxy resin in the house construction, describes many additional procedures that will be required when using resins, provides more details on the design of the scaffold, and shows a side–access portal to connect to an MEV.] 

On the first flight to Mars, a pioneer will be conveyed in his or her own habitat and Environmental Control and Life Support System (ECLSS).  These are a part of the NASA Multipurpose Crew Exploration Vehicle “Orion”1 or the SpaceX Mars Colonial Transporter2.  In order to build a real colony, however, the Pioneer will need to build his/her own structures out of native materials.  The high cost of bringing raw materials to Mars will always motivate the use of techniques that minimize the materials brought from Earth and maximize the value of any tools and equipment that are imported.   He/she will need to build the Mars equivalent of a log cabin, but without the trees. 

An effective construction strategy for Mars will entail 1) a thoughtful choice of a location for a village; 2) the use of native materials to the extent feasible; 3) the careful choice of tools and equipment that are low mass but highly effective, and 4) the employment of well known techniques from Earth adapted to Mars.  The process of construction will require energy for small and medium size motors for tools, trucks and heat producing equipment.  In this article it is assumed that the colony will have access to methane motors for all the equipment to be used.  (How the methane will be produced is another subject.)  In this article the Author will spell out a construction strategy and various building techniques based on his lifetime of both blue collar and white-collar careers and both hands-on and technical research.

 

Building in Stone

Pont du Gard Roman AqueductA Mars pioneer village will employ the two most common Mars materials, basaltic rock and regolith.   The first example of construction will be a village house that looks like a cross between a Quonset hut and an igloo.  The unit of construction will not be a regolith brick, however, because of the high temperature (1200 degrees C) that must be reached in a kiln to produce bricks.  This would be difficult to achieve without substantial investment in heavy kiln equipment and high-energy usage.  Instead, stone blocks will be employed.  This assumes that the village site that is chosen will be close a good source of un-fractured stone with a moderate hardness, possibly an escarpment.  A pioneer can cut and accumulate standard-size blocks and truck them to a building site as needed.  A small quarry operation can be started using a diamond-bit chain saw to rough-cut blocks from a cliff and a diamond-bit circular saw to ensure accurate dimensions.  These are relatively low-weight and low-energy tools commonly employed in stone quarries on Earth. Only an experienced quarry operator, however, should carry out blasting.

The Quonset structure to be constructed is based on the methods and experience of highly successful stonemasons of the Roman Empire.  The famous Gordon River aqueduct shown in the above figure is an example of the Roman arch design, a structural element that is noted for its high compressive strength and durability3.  In addition, modern geological studies4 and engineering analyses5 have shown that basalt, a common type of stone on Mars, also exhibits impressive tensile strength, more than enough to constrain the air pressure of Earth’s atmosphere at sea level. This strength combined with the power of high-tech epoxy resin will allow an airtight vessel to be constructed that will provide a protected, but livable environment similar to life on a submarine.

The Roman arch is a half-circle with each end resting on a square pillar of stone.  In the Roman technique, the stone pillars were constructed first, and then a wooden scaffold was built in the shape of the arch. This scaffold was used to support the stones of the arch during construction.  Blocks were set in place with mortar between blocks, starting from the sides.  The last block to be installed, the keystone, was wedged into the top of the arch until the pressure against each block in the arch relieved pressure on the support scaffolding.  When all the mortar had set then the scaffolding was removed and the next arch was begun4. This technique will be employed, with modifications, to build a stone house of standard dimensions in the Mars village.

Roman Arch DoorwayThe example Quonset house to be built will be a modest 400 cm wide by 1920 cm long and 210 cm high at the sidewalls, which will also serve as support pillars.   An arch of 2 m inside radius will rest on the two sidewalls; this arch will create 4 m of headroom at the center of the floor.  Wall and floor materials will consist of stone blocks.  The adjacent picture shows a Roman arch used for a doorway whereas the Mars house will use an arched ceiling over the entire facility.  It will be an airtight compartment built from naturally occurring materials. 

Before the block-laying may commence a plan for the structure must be laid out.  The layout for the building should lie within the perimeter of a planned village.  It is presumably located on a relative flat, rocky surface that is not far from the Mars transporter landing site.  It should not lie directly on the cryosphere (for reasons that explained in the article “Pioneer Ice Mining.”). The ends of the Quonset will contain the portals, docking ports and windows; they should face away from the west where the planet-wide dust storms will come from.  A gradual slope away from the portal is also desirable to help keep regolith dust from accumulating in front of the exit. Portals facing the sun will be preferred to portals in shadow because of the extreme temperature differences between sunshine and shadow areas.  

 

Preparing a Site

Like construction on Earth, walls must rest on firm footings and the foundation stones must be laid on well-prepared ground. The first step is to prepare the ground (rock and regolith) in the area where the house will be placed.  A ground area 8 m by 25 m will provide a suitable site to accommodate a house 4 m by 20 m (interior area) and 30 cm thick walls and 15 cm additional margin on the outside foundation blocks. This area must be perfectly flat; however, an additional 3 m area around the perimeter is desirable for the comings and goings of construction vehicles, but it does not have to be perfectly flat.

Preparing a site is not just a matter of digging into the ground with a backhoe because there is no topsoil or clay in which to dig as there is on Earth. A tractor-tread front-end loader with a standard bucket can prepare the ground.  An additional loader equipped with a breaker attachment (see the article “Mars Village Vehicles”) may be required if the ground presents many rock protrusions that are not loose stones.  The long direction of the 8 by 25 m site will usually lie across the surface grade of the terrain.

Grading & CompactingTo level the area the loader driver should begin at the higher side of the site (determined by visual estimation), cut into the ground to remove rock and regolith and use it to fill the lower side. When the jutting rocks have been broken up, the loose rock debris should be pushed to the low spots to build them up while small gravel should fill in the cavities between the rocks. The smallest remaining interstices should be filled with fine-grained regolith. The tractor-tread loader should smooth out and compact the final layer of soft regolith, about 10 cm deep.

Once the area appears to be flat, a transit should be employed to ensure a level area and to lay out the floor/foundation blocks in proper alignment.  This is the most difficult step in building the Mars stone house. On Earth, only the tops of cement forms of a foundation need to be level and the bottom can be very uneven.  On Mars, however, we are constructing the floor and foundation directly on the ground and it must be as level as can be achieved. Any unevenness will show up in uneven floors and walls.

The regolith used for the top layer needs to be cleaned of rocks, either naturally or by a regolith screening machine. Relatively clean regolith may be found in nearby dunes or drifts that lie downwind from ridges. If there is insufficient regolith in the vicinity of the building site then loads of regolith may be hauled from further away. A dump truck is ideal for this purpose but a pickup can be employed in a pinch. Either vehicle will require a rudimentary road to be constructed from the regolith site to the village construction site. (Refer to “Pioneer Road Building” to see how this is accomplished.)

The surface must be well tamped to create a flat horizontal surface.   A mechanical tamper will be preferred for this purpose, but the treads of a front-end loader may be sufficient to compress the ground.  To create a house that is squared in all directions, a transit will be employed, especially when laying the foundation stones and first row of sidewall stones.

 

Handling the Blocks

 BlocksThe principal stone blocks to be stacked into the structure are shown in approximate relative scale in the figure below.  The foundation/floor block is the largest and will be laid directly onto the prepared ground.  At a Mars weight of 238 kg it will require a front-end loader or a loader converted to a forklift (auxiliary attachment) to lift and place these stones into position. A small crane is also a suitable tool for this job.

In this version of the pioneer house all stones will be “glued” together with epoxy resin that is selected for the particular conditions on Mars, especially the very low air pressure. The mortar that would normally be used on Earth will not work on Mars because the water will sublimate so rapidly from the mortar mix at near-zero pressure that it will not have time to “set.” Epoxy resins employ a chemical reaction that involves a “hardener” that is not a solvent so is not considered volatile. As of this writing three companies have suggested particular products to be tested for this purpose or referred to a particular product selection guide. All products that are tested will require special construction procedures to ensure their successful use on Mars. For additional information concerning the use of epoxy resins, go to Resins for the Red Planet.

To lay the first cornerstone, set up two string lines that intersect at the exact location of the two outer edges of the block. Lay the cornerstone as accurately as possible using a front-end loader with a forklift attachment or with a crane. (See Spycercrane described in Mars Village Vehicles.) The method of joining blocks will be first, to prepare each surface with epoxy resin, and second, to gently slide one stone against the other to join the surfaces, using the forklift tines.  The first block must be held in place so as not to disrupt its position.


One method is to employ a block positioner made of metal as shown in the sketch below. It entails three long spikes driven into the ground to hold the cornerstone in place in two directions. It may be necessary to prepare the ground where the spikes will be driven to eliminate large rocks that could stop the stakes from penetrating the ground.

Metal Positioner

The driver of one front-end loader should place his bucket against the cornerstone just above the positioner. This will add more mass to resist the cornerstone being moved when the second block is pushed against it. Then a shallow trench about 1/2 cm deep and 10 cm wide should be scraped out in front of the cornerstone, as shown. A flat-edge trowel will be suitable for a shallow trench. This will prevent regolith from mounding up against the face of the cornerstone. Then apply the epoxy resin to the stone face to be joined. The second driver can now push the second stone against the cornerstone to begin the joining.

 Pipe ClampsWhile the epoxy resin is undergoing an initial curing phase, it will be desirable to maintain pressure against the joints. This can be accomplished without having a loader pressing against the blocks for the whole duration. As a temporary measure, a pair of pipe clamps can be used to hold a row of blocks together (See adjacent photo.) Lay a length of galvanized pipe over the row, then place the clamps over each end of the pipe and snug them up to the blocks. Rotate handle to apply pressure.

Pipe clamps are a temporary measure because it will become necessary to release pressure in order to add blocks to the row. In addition, they can only apply pressure in one direction since placing pipe clamps on a row in the perpendicular direction would interfere with the first row.

 


To apply pressure for a longer period, hitch a chain and ratchet to each of the four sides of a rectangle of blocks. Place corner blocks on the four corners of the rectangle. Attach a chain to a corner block and to a ratchet turnbuckle. Attach a second chain to the ratchet, then to a spring, and then to the next corner block. The four ratchets must be tightened at about the same time.

Ratchet Turnbuckle

The purpose of the springs is to safeguard against the severe temperature changes that can occur overnight. As nighttime arrives, the lower temperature will cause the metal chains to shrink so that the ratchets must be tightened. When daylight arrives once again, the chains will tighten and the springs will prevent the force of expansion from exceeding the breaking strength of the chains.

Brick Oven Before this marriage between blocks may commence, preliminary procedures must be carried out to overcome the conditions on the Mars surface, namely, the cryogenic low temperature. To this end, all stone blocks must be prepared before the day of construction by warming them in an oven. Ironically, an oven could be easily built from stone blocks using the techniques proposed for building the house; however, we mist start somewhere, so the oven will have to be imported from Earth on one of the early flights.  It can be comprised of lightweight panels that are fastened together onsite, but the oven must be large enough to accommodate the number of blocks that will be laid in a day. It will utilize a methane-oxygen burner and circulate heated gas, probably CO2-air from the atmosphere at low pressure. It must have a large door so that a forklift driver can load blocks into it (heating of blocks will have to be suspended while the door is opening and closing.) . The door must be as airtight as feasible so as to minimize the heated gas loss as much as possible. Operating at low pressure will also help minimize gas losses but will slow the heating process. 

Stone blocks cannot be heated quickly because they are likely to crack, so the heating period in the oven may be one or more days. The temperature of the stones that are joined must be compatible with the temperature range required for the resin to harden, usually about 65 to 120 degree F. Once a block is removed from the oven, the loader driver will race to lay it in place before its temperature drops below the required level; however, the surface of the stones that are laid can continue to be heated during and after they are laid. A construction site gas heater represents one method. Care must be taken with a gas heater because a flame can easily become too hot if held in one place too long; the stone will crack or the resin temperature may exceed its displacement value. Another method is to lay an electric blanket over the blocks, which can help counteract the extremely cold ground during a Martian night. Regardless of precautions, some loss of temperature should be expected, considering that the blocks will be in direst contact with a very cold surface. After the house is built, pressurized and heated, the resin may harden even further. Perhaps the best we can expect is that only the upper 10 cm of a 30 cm block will be fully hardened, but that should be more than enough joining power. 

After joining, the positions of the two blocks should be checked using the transit. Positions of all the stones should be checked frequently.  Regardless of the care taken, the flat ground will likely become disrupted by activity. Checking each stone before mating is the last chance to add or subtract small amounts of regolith under each block to ensure a flat surface along the top faces of the blocks.

 

Using the Scaffold

Once the floor is laid the first sidewall can be erected in conjunction with the raising of the scaffold frames. Beginning at one corner, stakes and alignment strings should be emplaced such that the junction of the strings corresponds to the corner of the first wall block. This point is 15 cm from the two outer edges of the underlying foundation cornerstone. The same general technique used to lay foundation blocks will be also be used to lay wall blocks. Each block must be preheated in an oven before being emplaced.

To build the standard Mars Quonset, an aluminum scaffold will be employed.  A permanent shell structure covered with regolith has also been proposed5, however, this requires more mass to be imported from Earth.  The recommended temporary scaffold is shown in the adjacent figure. The lower two halves of the framework consists of two nearly square segments, 200 cm wide by 210 cm high. The horizontal and vertical members of each segment consist of aluminum el-bars that are welded together at junctions and further reinforced by aluminum plates, as shown. When it becomes time to employ the scaffold, the segments are bolted together through holes on one side of each el-bar. After one section is finished, the segments of each frame will be be detached and reassembled for the next section of the house to be constructed. 

The upper four segments of the frame consist of curved, inverted tee-bars of different lengths, each taking the shape of a circular arc segment with a radius of 200 cm.  The radial members consist of aluminum El bars, like the members in the lower segments. The radial members have holes for bolting together the frame segments.

Frame of a scaffoldThe length of wall and ceiling that are constructed at one time represent one section of a house.  Each section of wall and ceiling blocks will be supported during construction by a series of scaffold frames that are placed 124 cm apart. The ceiling arch space between each of two frames will be filled with a flexible support blanket composed of square aluminum tubes that lie parallel to one another. Small round tubes will separate the square tubes from each other. To loosely hold the support blanket together, a wire rope will pass through holes in the square tubes and through the separator tubes. Five such wires ropes will be required for each blanket. A crane will pick up one blanket, lift it over the space between two frames, and then lower it onto the curved tee-bar edges of the frames. One blanket will cover one half the ceiling arch, over segments 3 and 4, while another blanket will cover segments 5 and 6. For further details on constructing and using the Mars house scaffold, go to Assembling a Scaffold.

The first row of wall blocks should be laid at the same time that the first frames of the scaffold are assembled. Each wall stone will weigh 119 kg Mars weight each so that a small crane with cable and tongs will easily lift it, but a front-end loader could also be used if necessary.  Each wall stone is placed onto the wall with the aid of a person in a Mars space suit (or in a Mars Utility Vehicle with manipulators) who will find them relatively easy to move horizontally to make small adjustments.  One row of blocks should be stacked and glued into each sidewall at about the same time.

 

Wall & Ceiling blocksOnce the first six wall blocks are laid in a straight line, the wall blocks on the opposite side of the floor should also begin to be laid. At this time the bottom two segments of the first and second scaffold frames should be bolted together and the first frame set into an upright position. One side of the frame should touch the first wall stone that was laid while the opposite side of the frame is used to mark the location for the first block of the second wall. A small shim can be placed between the frame and the block as it is laid.  It is necessary to leave a small space between them so the temporary scaffold can be easily removed later.

The first two rows of sidewall blocks can continue to be laid, setting up the frame segments as the work proceeds. This sequence should ensure that the scaffold and walls are aligned properly with each other. The first row of wall blocks should terminate just past the last scaffold frame. The number of frames that will comprise one section may depend on the length of the house to be built or may be limited by the number of frames that are shipped to Mars at any one time. They are designed to be reused; therefore a house may built section by section with the frames disassembled and reassembled as needed after each house section is constructed.

 

Building the End Walls

After all wall and arch stones have been installed, the two ends of the Quonset must be enclosed.  Constructing the end walls is the same process as building the sidewalls except that each of the rows of stones that intersect the curved arch ceiling must have end stones with one side curved to match the curve of the arch.  The curve of the end-stones for each row will be different because the curve of the arch will be different.  If the saws available to the pioneer cannot cut a curve into the stones then an angled shape will be substituted to approximate the curve of the arch. The remaining gap will be closed in by rock shards and regolith powder and sealed off by epoxy resin.

The end walls of the house will accommodate portals, doors and windows.  A Mars house portal will be analogous to a hatch and door used to permit an extravehicular activity (EVA) from the ISS as shown in the adjacent photo.EVA Hatch This is because going outside a house on Mars will be the equivalent of an EVA from a spaceship.   If the person is clad in a Mars spacesuit then he will use an EVA hatch similar to an ISS hatch.  The difference from this picture is that the hatch and door will be mounted vertically on the end wall of a Mars house where the room inside is a pressure-controlled EVA room.

The end walls will also be the location of portals for a colonist in shirtsleeves who will enter into a Mars EVA Vehicle (MEV).  These MEVs will be the construction vehicles by which colonists will build houses, roads and storage tanks. (See the article “Mars Village Vehicles.”). The MEVs will allow the colonists to work in their shirtsleeves within the cabs of trucks, front-end loaders, and utility vehicles. At this time there is a need for different types of connectors to these various vehicles because of their different configurations. Standardized passageways may come later.

Space Exploration VehicleThe adjacent figure shows a NASA Space Exploration Vehicle, another type of vehicle that may connect with a Mars house. NASA developed this method to connect the SEV to the NASA Habitat Demonstration Unit (HDU). It employs an airtight passageway that is flexible and compressible like an accordion. It provides the capability for an astronaut (or a colonist) to enter a vehicle from a habitat in his/her shirtsleeves with no change in air pressure and without a spacesuit.  The vehicle provides the necessary ECLSS equipment separate from the habitat system. 

A colonist will require the same type of passageway to enter an MEV from a Mars house, so the NASA connector was adopted for MEVs. The figure above could represent a “visiting vehicle” to a Mars house.  The main difference between an SEV and an MEV passageway is that the MEV doorways will be smaller (about 100-cm square) to provide a crawlway. The passageway to the MEV will be the same type of flexible tube with an adapter at the end.  Trucks will require side-to-side connectors like the one shown here, but a front-end loader will require a roof hatch. Access to the loader will be through a garage attic, which was sketched in the article “Mars Village Vehicles.” A Mars utility vehicle will have an appearance like the SEV but smaller and equipped with manipulators in front. It will not have the suitports or rear-mounted equipment; it will back up to the house and employ a rear-mounted hatch to connect to the house. 

A window is another feature that could be placed into an end wall of a Mars house.  It will be an unlikely feature in the early stages of Mars development because it would have to be imported from Earth, an extravagance, or built in a Mars glass factory.  Factories will be constructed at a later date in colonization.  When a door or portal is installed into an end wall then the row of stones that encounter the object must have end stones that are curved or sloped to accommodate the shape of the object.  Any gap around the object must be filled with basalt shards and regolith dust and then sealed with epoxy resin. 

To complete the floor of the house, any cracks or joints that are not already filled with resin will now be filled. Note that basaltic floor blocks may sometimes exhibit sharp edges that could be hazardous.   On Earth, a surface coating, such as polyurethane (PUR), would be applied over stone floors and would cover any rough edges. It would provide both a sealant and a surface covering.  Because of its transparency, the beauty of the underlying building material would be exhibited.  However, the feasibility of applying PUR in an extreme environment has not been tested and applying it in an enclosed temperature and pressure-controlled environment will create vapors that may be unhealthy.  When the interior has been pressurized and heated a water-based (latex) paint may be applied over interior surface.  A white ceiling paint will amplify the reflectance of otherwise dark enclosures and may enhance the livability of a cavern-like habitation.  Other light colors will provide an opportunity to decorate as well as brighten the interior. 

When the basic stone structure of the Mars house is complete, the entire house, except for the end walls with portals, should be covered with at least 2-1/2 m of regolith and rocks, firmly tamped.  This provides insulation from extreme nighttime temperatures and also from GCR radiation and micrometeorites

Once the house is completed and pressurized, the compression strength of the house is no longer the main concern. Rather, the concern will be the tensile strength of the structure to keep the indoor air from leaking out against a near zero outside pressure. To address this issue, the author conducted an analysis of the tensile strength of a basaltic stone house, which found that it has a large safety margin. To view this analysis go to Pressure Problem.

 

Utilities

In an Earth home, utility lines are hidden inside walls, above ceilings and below floors.  In a Mars house these spaces lie outside the insulating protection of 30 centimeters of basaltic stone and regolith and may be uncomfortably close to the extreme cold of the ground.  As a safety measure, utility lines and facilities will be located inside the protected environment of the home.  As much as feasible, the Mars house will contain all the modern comforts of a home on earth, including many high-tech conveniences.  Utility lines and electronic facilities may cause the interior to appear more like a space station than an earth home.  The utilities to be considered in this article are as follows:

PEX water pipe

  1.  Water lines.  It will be feasible to construct a community water supply system, which includes a water tank located at a high location.  From this water source each house can be provided with a chlorinated polyvinyl chloride (CPVC) water line under pressure.  Gravity flow may not provide sufficient pressure on Mars, in which case a pump will be used to supplement gravity.  The exterior water line will usually be 1 inch in diameter and made of PVC, which meets the standards for water lines as specified by the American Society of Testing and Standards (ASTM}.   Such PVC pipes will initially have to be imported, but they will ensure the safety of the pioneers and provide the convenience of running water in kitchens, lavatories, and laboratories. Inside the house, one 3/4-inch water line made of cross-linked polyethylene (PEX) will be placed inside the structure along the floor-wall junction with branch lines to serve sinks, toilets and showers.

(2) Hot water.  Separate pipes will not be needed for hot water because a compact hot water heater and dispenser will be provided at each sink to supply hot water on demand.  This will eliminate the weight of extra plumbing pipes and a central hot water tank. PVC Pipes and Joints

(3) Waste water.  On Earth, four-inch PVC foam core pipes are frequently used to collect waste from toilets and sinks in new homes.  On Mars a three-inch collection line will save weight in shipping from Earth and will perform adequately.  The waste line will be located in the same floor-wall junction as the water line, but above it. Waste pipes will be placed on shims or small blocks to provide a slope along the entire length from waste generation facility to waste treatment facility.  On Earth a slope of 1/4 inch per foot (0.85 cm per m) provides a slope that will carry waste solids along without clogging.  In Mars’ lesser gravity a slope of 2 cm per m may work better, but actual experience will set the Mars standard. 

(4) HVAC.  On Earth, heating, ventilation, and air conditioning (HVAC) are provided via a central system that collects air from all parts of a house using a system of metal ducts.  Air is filtered, then heated or cooled in a centralized device according to the setting on a thermostat and redistributed throughout the house by means of another set of metal ducts. 

For Mars, the air conditioning part of the system will be facilitated because the ambient conditions will only range from cold to extremely cold.  Unlike outer space there will always be a nearby air or ground heat sink where excess heat can be dissipated.  The air return ducts will collect any contamination that is accidentally introduced at a given location that could otherwise spread throughout the interior.  This is particularly important in a completely enclosed habitat.

 Ceiling used in a duct sidingA convenient, out-of-the-way location for HVAC ductwork is the stone ceiling.  To save weight on imported ductwork, the ceiling arch will be used as one side of the ductwork, as shown in the figure below.  The air distribution duct is under positive (high) pressure whereas the return air duct is under negative (low) pressure so a much larger duct is required.  Large vents will be inserted at a few positions along the return air duct.  These will be convenient locations for filters to protect the air circulation motors from dust.  Return air ducts will have branch collectors for facilities where potentially contaminated air needs to be captured, such as a laboratory hood or a cooking stove.

 

The central heating and ventilating unit will remove vapors and particles from the air stream and will supply heat as needed according to a thermostat setting.   Clean air will leave the central unit under fan pressure and enter the air distribution system.  These ducts will generally subdivide into branch ducts to deliver air throughout the house except to the pressure-controlled EVA room, which will require its own isolated system for safety.  The ventilation system will require more detailed design specifications by an engineer to achieve airflow balance throughout the house and proper functioning of the central unit.

(5) Electrical system.  The Mars house will require electrical power from a community system that will generate electricity by means of nuclear or photoelectric power and batteries.  (Later, methane-oxygen generators may also be employed.)  This system will be much like the International space station and the ISS electrical system will be the model for the Mars house.  In this design, photovoltaic arrays and power storage batteries produce electricity at 160 Volts direct current (Vdc), the primary system.  This power is delivered to a DC-to-DC Converter unit (DDCU) that provides a nominal 124.5 Vdc for a secondary power system within each ISS module.  (See drawing).  Since each module in the ISS may be owned by a different country, each may use power from the DDCU in a different way within their own facility.  Like an ISS module, a Mars house will contain a secondary system of copper wires to deliver 124 Vdc to the various electrical facilities.   Each house will utilize a Remote Power Controller Module (RPCM), which is a box with multiple switches with different load ratings to distribute power to facilities with different load requirements.  Wires to each facility will be color-coded according to their usage in the facility and will be installed within electrical conduit for protection.   The conduit will be attached to the ceilings near the ventilation ductwork but not in contact with it.

Floor Layout A wiring diagram will be required for the Mars house; the designer of the electrical system will create it before the Pioneer leaves Earth.  The details of the electrical system will be drawn up when the usage of the house is known in detail.

In addition to utility systems, other features and facilities will be required to make the house useful.  Partitions and walls will be constructed to create rooms for various activities.  To continue the use of in-situ resources, semi-permanent partitions will be built with small stone blocks similar in size to common bricks on Earth.  A practical sized block for this purpose could be 10 cm by 20 cm by 6 cm high.  These can be stacked in staggered cross-wise fashion with a drop of adhesive on each brick, This will create a 20 cm wide partition that will stay in place when bumped, but can be taken apart and the blocks reused.  A single-width 10 cm partition will be used where space is at a premium (which will be almost always).

One possible room arrangement is shown in the adjacent figure. The two exits at the top of the page (facing east) accommodate the two types of EVA trips that can be taken.  The first room, on the right, is for a person donning a Mars space suit and will exit through an ISS style hatch.  This type of EVA requires a sealed-off room where depressurization procedures can take place before a trip outside and for re-pressurization afterward.  This procedure is required because the pressure and oxygen levels are different in the house and spacesuit.  The wall between this room and the rest of the house must be airtight and therefore must be built in the same manner as the exterior walls, with cracks sealed by brazing.  Two airlock doors are required, one toward the house exterior and the second toward the rest of the house.  This creates a separate space where air pressure can be controlled independently from the rest of the habitat.  In the figure, the interior door for this room is inserted into the wall of the second room for efficient use of floor space.

The second EVA room (left) is for the use by a person who will drive a Mars EVA vehicle (MEV) that has the same pressure as the house.  This room also has two doors, but only for safety reasons, to seal off the room in case of an accident.  Otherwise a person can proceed directly to the MEV attached to the exterior of the door, enter it, perform a checkout, and begin the EVA.  (Some of the purposes of an MEV are illustrated in another article, “Pioneer Road Building.”)

 Raised ToiletBelow the EVA rooms is a space divided into three bedrooms by partitions, indicated by dotted lines.  This is an expensive concession to the concept of privacy because if the same space were occupied by three-tier bunk beds and no partitions then 36 persons could theoretically be accommodated.  With partitions and two-tier bunks, six persons will be relatively comfortable.  A decision must be made whether the initial standard will be like a submarine or like a middle class house on Earth.  As the Mars pioneer gains experience and proficiency in building with basalt blocks, the size and space created by arched structures can be expanded considerably.

This house layout shows a water usage and wastewater collection facility, or in EarthSpeak, a bathroom.  On the other side of the wall from the bathroom is a sink for a kitchen.   Note that plumbing facilities are grouped in the same vicinity.  This arrangement minimizes the amount of plumbing pipes required.  Note that the wastewater collection pipe was installed above the floor level so that a standard toilet, if used, must also be raised.  This higher position will allow gravity to be employed for wastewater flow.  (Also note that above the toilet is good location for a return air vent.)  On the opposite side of the bathroom is a laboratory shown with two sinks, thereby grouping these sinks and pipes in the same plumbing group as the other water-using facilities. 

At he bottom of the house layout is another exterior door that is presumed to exit into other hallways, houses, or Mars structures rather than the outside.  One of the useful structures to be built will be a four-way hallway intersection illustrated in the figure below. This is a 4 m by 4 m room with a raised ceiling such that each of four houses or compartments can be joined directly into a flat vertical surface and made airtight.  This structure can be built using the same tools, equipment, and block laying scaffold that was used for the first house, thus saving the amount of materials to be imported.   Each of the four walls of the intersection will contain an EVA door (portal) that is used to exit to the outside or to enter another house or compartment.  Each compartment should also have its own ECLSS system.  The policy of using multiple portals and ECLSSs is an expensive safety feature, but in the case of an accident in one of the compartments, it could save pioneer lives that are even more expensive.  Note that this figure and other sketches do not show the regolith that would actually cover each compartment.

Inter House Portal An intersection room can be employed to connect the original house to various other compartments that will use the same basaltic block building procedures and scaffold.  Some of the types of compartments are as follows:

* A hallway and equipment-storage facility, perhaps leading to another intersection;

* An additional house;

* A greenhouse/food production unit (a subject for another article);

* An outdoor garage used for MEVs (a subject for another article); or

* A laboratory, repair shop or small-scale industrial facility.

             The construction strategy and block building components recommended in this article are easily adaptable to a toy set similar to “Legos” and may be one of the first profitable spin-offs from The Mars Pioneer handbook project.  Please contact the Author for permission.

 

Summary

The expertise of ancient masons will be employed to construct a standard size Mars house using basaltic stone blocks.  Updated techniques will be employed to build a Roman style arched ceiling; a temporary portable scaffold will be employed to hold the blocks in place during construction. Instead of mortar, epoxy resin will be dispensed onto the faces of stone blocks to glue them together and form an airtight habitat. Utilities will emulate middle class amenities of an Earth home including running water, a heating and ventilating system, waste collection pipes, and an ISS-type DC electrical system.  Colonists will exit to the outside through two types of “EVA” rooms with NASA-compatible ports.  One exit may be a passageway to a Mars Utility Vehicle. An example floor plan includes a bedroom, kitchenette, lavatory, and an office/laboratory.  A four-way intersection room will allow for expansion to additional modules.

 

References

 

  1. NASA, “Preliminary Report Regarding NASA’s Space Launch System and Multi-purpose Crew Vehicle;” January 2011.
  2. Coppinger, Rob, “Huge Mars Colony eyed by Space Founder Elon Musk,” space.com, November 23,2012.
  3. “Architecture of the Early Empire’” State University of New York at Oneonta, Retrieved 6-20-2014 from http://employees.oneonta.edu/farberas/arth/arth109/arth109_sl14.html
  4. (3) R.A. Schultz, “Limits of strength and deformation properties of jointed basaltic masses,” Rock Mechanics and Rock Engineering (1995) 28 (1), 1-15.
  5. IonMars, “Pressure Problem – An Analysis of Air Containment in the Mars House” (2014) Posted on NASApaceflight.com Re: Specific Mars Colony Development and Planning, Reply #353 posted 08-03-2014 (with attachments).
  6. “Construction Techniques in Ancient Rome” Rome Art Lover’s Web Page, Retrieved 3-28-2014 from http://www.romeartlover.it/Costroma.html
  7. Ruess, F., J. Schaenzln, and H. Benaroya, “Structural Design of a Lunar Habitat,” Journal of Aerospace Engineering, Vol.19, Issue 3, 2006.
  8. NASA (2012) YouTube “ISS Update: Z1 Spacesuit and Suitport Testing,” Retrieved June 10, 2014 from http://www.youtube.com/watch?v=-tDuwIu_b9g