Architecture as Mole Hills
Architecture as Mole Hills
Sometimes you need to see something in your minds eye to make it real.
This is a discussion of one possible architecture for lunar settlements. There are many other possibilities. This one assumes that large mining machines, called sandworms, have been used to dig trenches while processing regolith for volatiles. These trenches are then used as the location for long inflated halls that are then covered with regolith for radiation protection.
Generations of Lunar Buildings
The first buildings on the Moon will be small construction sacks prefabricated on Earth. These will be sitting on the surface with regolith piled against the sides and sandbagged on top. They allowed people to stay on the Moon only for short times as they do not provide enough radiation protection. These will later be recycled to make new buildings.
This first generation of buildings, with their supporting facilities, is best described by NASA documents and graphics. Where we are most interested in here is the following generations of buildings that can actually support settlement.
The second generation of buildings will be very similar to the first but buried in the regolith. These will provide enough protection to allow people to remain between trips for the first time. Each building had one airlock and was surrounded by surface equipment like solar and thermal panels.
These buildings were the first toe hold in the Astronaut time period, but will be phased out early in the Mining period as they do not provide enough living space nor have enough radiation shielding for long term occupancy.
Some of these second building still remain for use as maintenance shacks at the science station and others for emergency out buildings.
At the time of our stories the living space has been expanded to a third generation with much more space and cellars with a high level of radiation shielding. These buildings are described below.
The Architecture described below consists of one story habitats made from inflated sections with solid end caps and buried in the regolith. For alternate ideas please see Architecture List .
Over All Appearance of a Settlement
All the main building, starting with the mining period, look like mole hills. They have an Earth prefab section at one end. Connected to this is a long tent like hall running in more or less a straight line for up to 100 meters. The hall is covered with 2.5 meters of lunar regolith for radiation protection giving the mole hill appearance. At the far end is a small prefab section that connects the hall to other halls.
One end or the other usually has an airlock assembly with a ramp leading down to the door. By the door will be a surveillance camera and tools for removing dust. The door will open inward in a complex manner like the door of a commercial air liner on Earth. This insures that the inside pressure is helping to keep the door seal tight and that the door can not be opened with any pressure on the inside.
The layout of the long halls is somewhat erratic as they are laid out to miss craters and may even be curved or bent to suit the lay of the land. Down each side of the halls is a borrow trench where much of the regolith was taken to cover the hall.
One hall, the gym, stands out visually as it is made in a circle of about 100 meters outside diameter. This allows for a continuous internal track.
Scattered among the mold hills are many pieces of outside equipment including tracking terminal arrays, solar concentrators, solar panels, antennas, a retro-reflector, and science instruments. All this equipment looks spindly and weak by Earth standards. It is all made from as little Earth material as possible and takes advantage of the Moon's weak gravity.
One small sandworm, about 1/4 the size of the industrial ones, remains in the building area. It digs trenches for new halls. There are also other mounds around that cover storage tanks and other industrial equipment.
Foot prints and wheel track run every which way. Footprints last a long time on the Moon. There are a few improved roads to the landing pads, to the mining areas, and to a science field. These are simply leveled and packed regolith with the craters filled in. Where the road from the landing pads arrives at the main building is a ceremonial plaza with a ring of flag poles.
In the distance there are a number of designated areas:
- Landing pads -- About one kilometer off for safety and to control contamination.
- Mines - Several kilometers off the sandworms dig long furrows 11 meters wide and kilometers long. They operate during all daylight hours digging the regolith in front of them and filling in the trench behind. The result looks a little like a plowed field from a distance.
- Bone yard - This is the junk yard is near the maintenance shop.
- Solar Field - This area is only a few hundred meters off and includes large solar collectors for power and large tracking radiator panels. It is situated on high ground.
- Science Field - A few kilometers off, this field contains many science instruments.
- Industrial equipment - Between the main settlement and the mines are a number of industrial constructions for refining the He-3 and separating other useful volatiles.
Notes on Radiation Shielding
The Earth provides two types of radiation shielding critical for life: atmospheric mass and magnetic field. The Moon has neither type. On the Moon, our architecture must provide all our shielding. This is so important that it drives the entire architecture of the settlement. For more details see Radiation Shielding.
The Basic Hall Structure
All buildings built in the mining and settlement periods are of mole hill construction. Calculations of some of the factors in this design are given in the spreadsheet, MalapertCal0n.xls. The three sections are:
- Prefab Utility Section - Containing all sanitary and environmental control equipment. This includes a bathroom, shower, launder, and environmental monitoring equipment. Also located there is a hatch leading to a cellar room. This section may contain an airlock assembly or have a simple pressure bulkhead connection to another hall.
- Hall - A long hall made of a multi layered plastic construction. The layers are supported by the internal air pressure but do need some reinforcement to carry the weight of the regolith piled above the hall.
- Prefab End - This section is usually a simple pressure bulkhead that allows communication with the next hall. In an emergency it can be sealed off.
The halls have a cross-section something like a loaf of bread. The roof is a curve supported largely by gas pressure. The floor is made of flat insulating panels with a top aluminum skin. Later these floors are covered with tiles made from lunar regolith. The walls are flat and sloped out about 10 degrees. The width of the floor is slightly more than three meters and the roof is almost two and a half meters high. The flat lighting panels make up the ceiling with tubes and cables above them.
Mole hill construction starts with the digging of a long trench by the small sandworm. Unlike its larger brothers, the small sandworm dumps the processed regolith outside of its trench and makes a ramp at both ends. This trench is about 3.5 meters (11 feet) wide and 2.5 (7 foot 3 inches) meters deep (by the beginning of the settler period this will be increased to 4 meters by 3 meters). Robot construction equipment then cleans out trench and digs a big hole at one end for the cellar room.
The prefab sections are then installed stating with the cellar. It is covered with back fill and the prefab terminal assembled above it.
The long tent structure is then unrolled down the trench and the terminating bulkhead is installed. The tent is then filled with the least valuable gas from the mining operation and looks the world for a party balloon.
Stiffeners are then added over the top along with utility conduits. Then the long tent is covered with regolith. The first layer is the very fine sand screened out during He-3 separation. Later comes the gravel and unprocessed regolith.
The internal atmosphere is then adjusted to support people and all the internal partitions, utility fixtures and furniture are installed.
Specific Types of Buildings
Here are some of the specific buildings a lunar settlement will need.
Basic Lunar Astronaut and Miner Housing
The basic lunar housing unit for individuals is a long narrow dorm room. The basic open hall structure is partitioned off so as to produce a narrow hallway parallel by long rooms. The partition is light weight but covered with painted graphics that make each doorway unique.
The basic room is about 2.30 meters (7 foot six inches) wide and about 8 meters (26 feet) long. It has a thin metal door. The room is sparsely furnished with a bed, computer desk, shelves, and storage cabinets. There are no kitchen or bathroom facilities, these are communally shared.
The computer monitor is large and flat. It can be turned so as to be seen from anywhere in the room. It can display exterior views (like it was a window), science graphics, TV programs and movies from Earth as well as computer output.
The Cellar Rooms
At one end of each hall is a cellar room. It is buried extra deep to provide protection during radiation storms. Zero to five such storms come each year and they last for a few hours to a few shifts (8 hours each). A system of spacecraft monitor the sun for such storm and provide thirty minute to eight hours warning. During a storm, exposure on the surface can be deadly and the level of radiation shielding in the halls is inadequate. During a storm every one must hide in a cellar until it passes.
The cellar room is about the same size and cross-section as an 11 meter (36 foot) section of the common hall and runs at right angles to it. It does have more metal struts in thick plastic walls to support extra weight. The cellar have about 7 meters (23 feet) of regolith shielding which makes them about as safe as a high altitude city like Denver or Mexico City.
Each cellar room contains a small head. It is also the permeate home of radiation sensitive equipment such as the environmental controls for the hall. At the hall end are storage cabinets with emergency equipment for use during storms.
The cellar is connected to the hall by pressure hatch that can be sealed. The drop through the hatch is 6.4 meters (15 feet). There is a ladder, but people often simply jump down. The drop takes about 2 seconds and you hit with a velocity comparable to jumping down 1 meter (3 feet 3 inches) on Earth.
The cellars have many uses from food storage to meeting room. Getting one for use as a personal living space is a huge perk.
Every person on the Moon has to do a strenuous workout every day to stay healthy. The gym is one of the most heavily used rooms in the complex. It is build like a standard hall except that it is made in a circle with an inside diameter of 80 meters (260 feet).
Against the outside wall is a continuous track. If you ware a track suit filled with iron pellets recovered in the mining operation (Ironman), you can almost run as if on Earth.
The inside wall of the gym is lined with computer terminals, exercise machines, and exercise mats. Many of the exercise machines have computer screens and speakers. These can be used for a variety of specially devised games, some of which involve competitions with people back on Earth.
Normal entrance and exit is through two cellar changing rooms at opposite sides of the circle. These have double hatches one of which comes up in another hall. These rooms alternately smell antiseptic or sweaty.
The viewing dome is a small room on top of hard walled room that allows people to view the outside surrounding and sky. Viewing the universe with the naked eye is now the most popular use of free time for people in space.
The Viewing Dome has a number of windows that have filters to prevent the bright sun from damaging your eyes and shutters to close off the views when the room is not in use to stabilize the internal temperature.
This room does not have as much radiation protection as most other room and can not be used during solar storms.
Each hall ends with either a pressure bulkhead connected to another hall or in an airlock to the outside. The airlocks are complex structures consisting of an outside ramp, the airlock, an EVA room for working spacesuits, and a head with shower.
There is a major problem with going from a space habitat to a spacesuit. The atmosphere used in a spacesuit needs to be the lowest possible pressure to allow ease of movement. This is a pure oxygen environment at 21 kPa (3.1 psi). The habitat will have a much higher pressure and the atmosphere will contain at least some nitrogen.
Standard Earth atmosphere is about 101 kPa (14.7 psi). The best atmosphere for a lunar base has not yet determined. In our stories it is assumed to be near earn standard Earth pressure but with different components. The inside atmosphere will have about 21% oxygen, a trace of carbon dioxide, a trace of nitrogen, and enough noble gasses (krypton, neon, and helium-4) to make up the pressure. The noble gases are a byproduct of the He-3 production. It will also contain enough water vapor to hold the relative humidity between 40% and 60%.
To go outside, a person will need to breathe pure oxygen for an hour or more to flush the nitrogen out of the blood. This is one of the purposes of the EVA room. The cleansing time requirement for the noble gasses is not yet understood. In our stories it will take a minimum of one hour to accommodate to the suit atmosphere.
Coming back inside is not easy mater either. Dust control is a major problem at all times on the Moon. Getting back inside can take up to an hour.
You approach the airlock from the outside by way of a dirt ramp. The halls are dug a little head high into the regolith. The sides of the trench and the regolith over the structure are stabilized with sand bags.
At the door is a grounded metal deck. Beside the door hang brushes on cables and above the door is a camera. You must brush yourself off thoroughly to be let in. If you are alone, you will need the help of a robot. Beside the door is also a connection to an oxygen supply and backup communication equipment.
The actually airlock is next and it can handle two people at a time, three in an emergency. It has a pressure door from the outside and a pressure door to the inside. This area is monitored very closely.
Next is the EVA room (Extra Vehicular Activity) it is an area devoted to the spacesuit. It includes aids for getting into and out of them. It has additional dust control to keep them clean. It has rack for storing them that include recharging for oxygen and power. There is a robot to assist if you are alone.
Next comes a full shower with changing rooms, drinking water, and an air shower for drying off. In the outside changing room are fresh interior garments.
The Mess Hall
The Mess Hall is one open standard hall without a partition. The kitchen at one end and uses the cellar as a pantry. As the miners are on three shifts to keep the sandworms working, the mess hall is in nearly continuous use.
It is also the only room big enough for all-hands meetings
The clinic starts as a room in a prefab structure. Later it grows to be a section of a mole hill hall. It provides regular physicals to all the people in the station as well as routine medical attention. It can address some types of major accidents but not all. Medical staff are limited. Research on long term humans living in space are usually going on.
People who are seriously hurt are probably also not well enough to survive travel back to Earth. Also the Moon is too distant to allow robot directed surgery directly from Earth.
Business and Meeting Rooms
There are several halls devoted to running the mining operation and science operations. Many of these contain full width areas with large computer displays that show base operations, science being done, or the operation of the mines.
A few of the smaller private rooms can be scheduled for personal use and are popular for movies, television, and parties. All of these rooms have major communication channels back to Earth.
The farm halls grow plants in a hydroponics system. Washed and screened lunar regolith is used for the base and organic material manufactured from waste treatment keeps the plants growing. The farms produce food, fiber, and oxygen.
The atmosphere in the farms had more carbon dioxide, water, and nitrogen than the normal mix. Most people find them stuffy and it is ill advised to go outside after breathing this air for any length of time. All disease organisms have been eliminated.
The farm halls are artificially lighted. They run on a 20 hour day and 4 hour night 365 days a year. This is not unlike the summer growing season in Alaska extended to all year.
One popular vegetable is the tomato. Under these conditions the normally annual tomato plant lives for about four years. It grows to cover a large area of trellis and has a stalk about 150 mm (6 inches) in diameter. Such a plant will produce many tones of fruit.
Only much later in the settler period is animal husbandry introduced. The animals are small and editable. They are not pets. They are important in making the settlement independent from Earth.
Most industrial equipment is outside. Some of it is independently buried. Some of it is very large and may have moving parts such as large arms.
This equipment converts the raw volatiles mined by the sandworms into useful and valuable substances. The most valuable of which is nearly pure Helium-3. Other products include oxygen, water, carbon dioxide, nitrogen, and noble gases.
By the time middle of the miner period, the factory also produces ceramic floor tiles, a variety of glass, steal, and titanium.
There are only a few commercial rooms inside but they are very important:
- Control Room - This is the heart of the He-3 mining operation. It is a long hall with many computer terminals and large displays. It has the most communications links back to Earth.
- Main Shop - It is first and foremost facility for the maintenance of sandworms, outside manufacturing equipment, life support facilities, and robots.
- Prototype Shop - The second repair shop can fix anything or build something new when needed. It is a favorite work area of all the Mooners and is used to develop many ideas for commercial development not to mention personal jobs and making gifts.
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