Design of a extra-terrestrial settlement
An engineering project
Nyssa Stephanie Rene Woods
1997 Grand Prize Winner of the NASA Ames Space Settlement Design Contest
Seton Home Study School, Grade 9
Teacher: Karen S. Woods, M.A.
The purpose of this project is to design a self-sufficient colony in space as a base for human habitation.
The design necessitated a good deal of study of areas as diverse as animal husbandry, structural stress loading, and waste management. Many of the detailed calculations were carried out by computer programs written by the designer.
Most of the design of the project involved "what-if" types of
speculation, looking at the data available, trying not to "reinvent
the wheel", making choices, then doing the "down and dirty" number
crunching. In other words, it was an engineering project.
One overriding goal lies behind this design. That is, once in place and operational, the colony must provide all of the necessities and luxuries for the colonists. It will be a self contained community in space. Nothing will be on the station which can not be made new, easily repaired, endlessly recycled, or replaced by the colonists. It will be long way to earth. While replacement parts may be easily obtained on Earth, the shipping charges- currently between $2,000 and $10,000 per pound- will be economically unsupportable, even though the station will be earning substantial sums by both building and repairing sattelite power stations and other sattelites, and serving as a platform for launches into deeper space for both unmanned and manned expeditions.
On first thought, the project seemed the stuff of science fiction. Yet, the science fiction of yesterday has had an almost disconcerting habit of becoming today's science fact.
Acknowledgements must go to the team who did the NASA 1975 Summer Study, to Mike Combs for his "Space Settlement FAQ", to Princeton's late Dr. G.K. O'Neill for his wonderful writings and his founding of the Space Studies Institute whose website was greatly helpful, to Dr. Krauss of Case Western Reserve University for his wonderful book about the physics of Star Trek, to the team who did the Tango III design, to IBM for the website of US Patents that the corporation maintains, and to Dale Greer for his "Constants and Equations". All of these were wonderfully helpful. Additionally, thanks are due to Karen Woods, the designer's mother and mentor, who actively encourages both solid scientific thought and speculative mental adventures.
Having made the preceeding pages of philosophical declaration, next on the agenda is a computation the amount of area necessary to meet these criteria. This will determine the type and size of the station which shall be built. Form, in this case, must strictly follow function.
With a maximum population of 300,000 persons, it is clear that massive areas will be necessary to provide living space, agricultural support, employment opportunities, mechanical life support systems, water reserves, et cetera. But, how much space will be necessary?
Since overcrowding has been linked in several behavioral studies to increases in violent crime, the colonists must not feel crowded. The suggestion of the 1975 NASA study is that each person be allocated at least 40 m2 of personal living space. 40 square meters, that's not much space, a little less than six meters by seven meters. Taking that suggestion, with a top population of 300,000 persons, we need 12,000,000 (twelve million) square meters for private living space, alone. That doesn't count the thickness of the walls. To insure adequate privacy, the exterior walls of dwellings should be thick (about 20 cm should do it) and heavily insulated to deaden sound on the general principle that a person's quarters will be the only place where he/she can truly let his/her hair down. The value of that privacy will be of immensurable aid to both the maintenance of mental health and social tranquility and will more than offset the cost in floorspace of an (approximately) extra .33 m2 per person or an extra 100,000 square meters of area for living space, bringing the total to 12,100,000 square meters of area. Assuming a height of 3 m in the residential areas, this yields a cubic meter requirement of 38,100,000m3.
In addition, each of those 300,000 people need to areas to eat, work (in a vast variety of occupations from trash collectors to college professors), shop, and care for personal hygiene. They will also need to have communal areas for social interaction, medical and dental care, education, enter- tainment, recreation, religious observances, as well as the docking of transport ships. Areas for such mundane, civil, activities as recording vital statistics and tracking the economic status of the colony would have to be provided. As, unfortunately, would areas for the incarceration of lawbreakers, either accused or convicted. Along with this would be office space for a security force. There will have to be areas for sewage treatment and water reclaimation/treatment, environmental temperature controls, and air filtration/purification/humidity control which will- by necessity- interface with water reclaimation, and recycling/trash handling. These last items need to operate seamlessly, unnoticed, and -like the areas for heavy industry- at some distance from the main living areas. How much area will be required to provide all of these things?
First under consideration is food. Few areas in the human experience have developed such social significance as food. Food is intimately connected with celebrations of great joy and times of deep sorrow. Reflect on the social significance of the christening parties, wedding receptions, and the post funeral gatherings in one's life. These are the times which draw a community together as a people and allow the community to multiply joys and divide sorrows. In the station, food will hold no lesser cultural and social significance. For the design of the station to treat it with any importance would be tantamount to inciting mutiny among the colonists. Yet, food- like all other details in the design process- is subject to design condition 3, that it be self-sustainable.
How much area will be needed to provide food for the population? The question is twofold. How much area is needed for the agriculture/aquaculture? How much area is needed for food preparation/preservation/processing and dining facilities?
Several designs that the author has looked at have assumed the presence of trees and livestock on the station. Those assumptions bear direct examination to determine whether or not they are supportable.
Trees are much praised for their ability to take CO2 and convert it to O2. Yet, frequently overlooked is the fact that in the absence of sunlight, i.e. at night, trees "breathe in" O2 and respirate CO2. If the light and dark periods are equal, there is a question as to whether the trees will actually be net producers of O2. This leads to the questions:
On the matter of trees, it is a rule of thumb taught to gardeners that there is as much tree below the soil as is above. It is pleasant to think about colonists being able to stroll down a tree lined boulevard, to stop and pull off an apple, peach, or pear from a tree, bite into the juicy flesh of the fruit, and to continue his/her walk while enjoying the sweetness of the fruit.
Yet, to achieve that, assuming a four meter tall dwarf fruit tree, the thoroughfare would have to be offset at least four meters from the floor of the structure and a container containing a depth of at least four meters of soil or other potting medium provided beneath the thoroughfare for the tree. The remaining subfloor space could be utilitized for storage- perhaps storage of agricultural tools. Assuming, as gardeners are taught, that the root structure of a tree will mimic the branch structure in width as well as in depth, then the container of soil or other growth medium would have to be at least four meters wide. Were those containers to be cylinders, that would mean that each tree would require a volume of 50.24 m3 of soil or other potting material. That same amount of potting medium would provide a planting bed 15m by 10m to a depth of 33.33 cm.
How many trees would be neccessary to provide fruit on a year around basis for the community? Assuming mature dwarf trees, i.e. trees at least three years old, producing- at most- sixty pieces of fruit per tree per year, assuming the consumption of three pieces of fruit a day (or equivalent in juice) by each colonist, that means that each colonist would require between 18 and 19 trees to provide fruit, or that the station would require between 5,400,000 and 5,700,000 (five million four hundred thousand to five million seven hundred thousand) fruit trees. That would mean that 285,000,000 cubic meters of potting medium would be required for trees, or 570,000,000 cubic meters of area for trees- both above and below "ground", assuming trees kept to a maximum height of four meters. The area requirement for trees would be into perspective, this would be the equivalent of 41,838.84 acres to a depth of about 13 inches. It's a huge volume of planting medium. Yet, the projected station population drives huge numbers.
Further, there is the matter of replacement trees. This would require additional area for the growth of nursery stock. Yet, nursery stock would only have to be grown towards the end of the estimated life of any tree, or if a tree would die from disease. Dwarf trees are a grafted tree with a root stock from one tree and trunk from another; a factor which increases the number of trees necessary in a nursery situation.
Darkening the outlook for fruit trees further, is the fact that all fruit trees of which the author has personal knowledge are autoallelopathic. They produce phytotoxins in the soil which make replanting the same type of tree in the same place nearly impossible. Yet, the planting medium could be recycled into planting beds for vegetables or another tree of a different kind planted in the former tree's space.
Trees are not totally out of the question, provided that the will exists to set aside the requisite area and volume.
On the matter of livestock, one has to wonder if those designers of other stations had truly looked at all the facts concerning animal protein production. The average American consumes about 120 pounds of beef a year. That's roughly about a third of a slaughtered beef cow per person per year. Using that average as a benchmark, the population of the station would need to harvest approximately 100,000 cattle a year (and find a use for the bones, hooves, sinew, blood, cartillage, intestines, etc. Although to be fair, the beef-by-products industry on earth does a good job of finding uses for these items. Similar uses could be found aboard the station, provided that the design allows for dogs and cats as pets. Yet, that's another question.). The herd would have to be at least twice that big to provide for continuation of the species. So, the station would have to support a herd of 200,000 cattle.
A single beef cow will consume about 70 pounds of food each day. Multiply that out- 200,000 cows @ 70 pounds of food per day per cow @ 365 days per year- yields 5,110,000,000 pounds of food that would need to be produced a year to feed the cattle, alone. (By the author's admittedly rough calcu- lations, the station could easily meet it's daily protein requirements with only one sixth of the grain and soy production which would be designated as feed for the proposed cattle herd).
According to the US Department of Agriculture, each cow will drink about 35 gallons of water a day. Similar calculations yield that this herd of cattle would require 7,000,000 gallons of water a day, or 2,555,000,000 gallons of water a year. The residents of the station, on the other hand, will consume- counting drinks, water for sanitation and personal care, water used to grow crops- at most, 20 gallons a day, quite probably a lot less, with good conservation measures. Still, people themselves would use- at maximum- 6,000,000 gallons a day for the entire station. But, most of those gallons for human consumption would be recoverable.
In addition, ruminant animals- cattle, sheep, camels, goats, etc.- produce methane in large quantities. A small herd of 200 cattle will put approximately 10 Billion metric tons of methane into the atmosphere during a year's time. So, the proposed herd of 200,000 animals would put 1x1010 metric tons of methane into the atmosphere of this closed environment.
Clearly, beef production, on this scale, is unsupportable simply on account of the demands on the air filtration and water systems.
The possibility of raising other non-ruminant animals aboard the station does exist. For example, chickens come readily to mind, as do both rabbits and hogs. According to the US Department of Agriculture, the conversion ratio, i.e. the number of pounds of feed to the number of pounds of meat recovered from the carcass, for each of these animals is about 4 to 1 which makes them among the most efficient of meat producers. The slaughter age of each of the animals is six months or less, which would yield several crops a year. The female of each species is quite capable of producing many offspring each year, assuring a continuing supply of fresh meat.
From personal experience, the author strongly discourages the raising of hogs. While hogs are not ruminant animals, the eye watering odor of large scale hog confinement operations is quite distinctive, to say the least. There's a saying in the country, when one passes a hog operation: "Smells like money!" Aside from the odor and sheer mess involved, pork is not a universally accepted meat. Judaism, Islam, and certain Christian sects prohibit the consumption of pork in any form. There will be enough stresses on the colonists simply from living in space. The design does not need to be knowingly adding religious controversies to the stress mix.
Rabbits. Peter Cottontail. The Easter Bunny. That's all most people know about rabbits. It's not a meat which most people in the US have much contact. The slaughter age for a rabbit, according to the USDA, is about 4 months. The prime weight (live weight) is about 4.5 pounds. Losses in dressing the rabbit would involve pelt(fur), organs, intestines, blood, head, and feet. A slaughtered rabbit weighs in at about 2.5 pounds. Since rabbit is so unfamiliar to people, the question remains as to whether or not it would be acceptable.
Chickens are more a more familiar creature to most people. The slaughter age of a chicken is about 3 months for a broiler. The live weight of a chicken at slaughter age is about 4 pounds. A dressed chicken- minus feathers, head, feet, and guts- weighs in at 3 pounds. The remaining flock will consume- with avidity- the inner parts of their slain members. A flock of 25 chickens consume only a gallon of water a day. Yet, chickens- raised in as tight of confinement as would be required aboard the station- would have to be debeaked as chicks. Otherwise, they would peck each other to death. Recent experience in Arkansas with pollution of streams by large chicken processors should stand as a warning about how easily the wastes in chicken production can get out of hand.
Therefore, simplicity's sake dictates that the community aboard the station adopt a strict vegan vegetarian diet which in addition to being easier on the environment, would virtually eliminate any interfaith disputes about day to day dietary restrictions. Additionally, such a diet would go a long ways toward eliminating a good many of the health problems which plague modern man.
So, how much area needs to be set side for the growing of crops? First, we must know what crops will be grown. Since the gardens will have to provide the seed for continuing generations of food production, the use of hybrid seeds is completely out of the question. So, with a vegan diet, as large of a variety in fruits and vegetables as possible will have to be provided, along with herbs and spices. The gardens will also have to supply much of the source material for pharmacopia. Additionally, the gardens will produce the basic materials for clothing. Much work has been done in commercial labs recently with the development of soy and corn based plastics and other ethylenes. Adequate growing area will be set aside to provide for corn and soy production targeted as source materials for industry to make those things needful by the colonists. And the gardens must produce copious amounts of compost materials which will eventually replace the initial potting medium, producing, and resupplying, real- rich black- soil aboard the station.
After much thought, this is the list of crops which will be grown within SCORE's gardens and arboretums, provided non-hybrid seeds may be obtained: Agrimony; Ajowan; Alfalfa; Angelica; Aniseed; Annato; Apples; Apricots; Arnica; Arugula; Asperagus; Astragalus; Bannanas; Barley; Basil; Bay; Beans- many both fresh and dried varieties including broad, green, pole, yellow wax, fava, lima, great northern, mung, pinto, red, black-eyed peas, kidney, soy, and others-; Bee Balm; Beets- especially Sugar Beets; Bible leaf; Blackberries; Black Cohosh; Blueberries; Bok Choi; Borage; Boysenberries; Broccoli; Broccoli Raab; Brussels Sprouts; Sprouting Broccoli; Burdock; Buchu; Cabbages- several spring, summer, fall, winter, and Chinese varieties-; California Poppy; Caraway; Cardamom; Carrots; Cauliflower; Celeriac; Celery; Chamomile; Chervil; Chicory; Chives; Cinnamon; Clover; Cloves; Coriander; Cornsalad (mache); Cotton; Cress; Cucumbers; Cumin; Dill; Echinacea; Endive; Eggplant- several varieties; Evening Primrose; Eyebright; Fennel; Fenugreek; Feverfew; Field Corn; Flax; Florentine Fennel; Fo Ti; Foxglove; Galangal; Garlic; Ginger; Globe Artichokes; Goldenseal; Gooseberries; Grapefruit; Grapes-several varieties; Heartsease; Hemp; Honeysuckle; Horseradish; Hot Peppers; Hyssop; Jerusalem Artichokes; Juniper; Iceplants; Kales; Kiwi; Komatsuna; Kohlrabi; Lavender; Leeks; Lemons; Lemon balm; Lemongrass; Lemon Verbena; Lentils; Lettuces; Licorice; Ligonberries; Lovage; Malabar Spinach; Marjoram; Millet; Mizuna Greens; Meadowsweet; Melons- various types; Mustard; Nigella; Oats; Okra; Onions- several varieties; Oranges; Oriental Mustards; Orris; Paprika; Parsnips; Parsley; Passion Fruit; Pasque Flower; Peaches; Pears; Peas; Peanuts; Pepper (piper nigrum); Peppermint; Plantain; Pickling Onions; Pineapples; Poppy; Prickly Pear Cactus; Popcorn; Pot Marigold; Potatoes; Pumpkins; Quinoa; Radishes; Red Currants; Red Raspberries; Yellow Raspberries; Rhubarb; Rice; Rosemary; Rue; Rutabagas, Sage; Salsify; Sassafras; Scallions; Scorzonera; Sesame; Shallots; Skullcap; Sorrel; Spearmint; Spinach; Spinach Beet; Stinging Nettles; St.John's Wort; Strawberries; Summer Purslane; Summer Squash; Sweet Cicely; Sweet Corn; Sweet Peppers; Sweet Potatoes; Swiss Chard; Tansy; Tarragon; Taro; Thyme; Tomatoes; Tomatillos; Triticale; Tumeric; Turnips; Vanilla Orchids; Vervain; Watermelon; Wheat- soft and hard; White Currants; Wintermint; Winter Savory; Winter Squash- acorn, butternut, patty pan, etc.-; Wood Betony; Woodruff; Yarrow; and Zucchini. Additionally several varieties of edible flowers will be grown both for food uses and to simply cheer the soul: carnations, violets, pansies, chrysanthemum, variegated geranium, cornflowers, gladiola, daylily (Hemerocallis), nasturtium, rose, freesia, sweet pea, and baby's breath. Bees will be necessary for best polination for some of the crops, which will result in a sufficient quantity of honey being available aboard the station.
Sample menus, representing diverse meals that could easily be available based on these crops, are available in appendix 1.
It should be noted that several of the plants proposed for growing on the station are narcotic, psychoreactive, or extremely hazardous -even lethal- when abused. As such, some of them are illegal to grow in many nations on Earth. There is a danger of abuse by including them on the station, yet, the benefits far outweigh the risks of abuse.
Since there has not been shown to be an adequate source of sodium on the moon, a salt substitute will have to be grown or salt made aboard the station. The absolutely easiest source for a salt substitute would be to take part of the soy crop and make Liquid Amminos from it, then to dehydrate the liquid, producing a salty, protein rich, powder which could be sprinkled on food. The next easiest source for a salt substitute would be to grow Kelp. Dried, powdered, Kelp has a salty taste and is a good source of both sodium and iodine. Kelp is a seaweed. So, this will require extra room and a special supply of water. The third option would be to chemically separate out sodium and chlorine from either organic or inorganic sources, purify them, then react them together to produce table salt. Both sodium and chlorine are highly corrosive gases, so care will have to be exercised, if that course is taken.
If the station is going to make the commitment to growing one kind of seaweed, it could grow others for food uses, as well. Carrageenan and agar- agar come immediately to mind. Carrageenan is a stabilizer widely used in the food industry. Agar-agar flakes can be used much in the same way that USP Gelatin (which the station will not produce given the absence of hogs) is used.
Some sort of recreational area could spring up about this, especially were it to be stocked with some kinds of bright tropical fish. After all, aquariums are frequently recommended to people suffering from stress. So, the area could be made to do double duty.
How much area for aquaculture? In the wild, Kelp can easily grow to a height of 40 m. It grows 10 to 14 inches a day. This growth rate, along with Kelp's chemical properties- it's rich in iodine, potassium, etc.- makes it an almost ideal addition to the station. The area for the tank will be ten meters volume, or a volume of one hundred thousand liters of seawater. This water, especially if it is to be host to finfish and shellfish, as well, will have to be recirculated between the aquarium and a reserve tank with a purification system between to filter out fish waste and reoxygenate the water. An allowance of 500 m3 should cover the sub tank and the filtration system. The aquarium would have to be carefully engineered on account of the structural stress which it would place on the station.
All of this brings us back to a consideration of how much area is necessary for the gardens. Rotating crops so that different foods are always available will limit the amount of space necessary. But, it is still a huge area. About 2,100,000 pounds of food will be consumed every day aboard SCORE, or about 766,500,000 pounds of food a year. Based on the agricultural productivity in the author's part of West Central Illinois, the means that each person will need about 1/2 acre of growing area. This assumes that production results similar to those of West Central Illinois can be achieved aboard SCORE. 150,000 acres (60,750 hectares) will be needed aboard the station for the growing of crops. That's a total of 607,500,000 m2, which will be needed for agriculture, excluding aquaculture, or 2025 m2 per person (about 100m by 20.25m).
Assuming planting beds .33 meters deep, that would mean 202,500,000 cubic meters of potting medium which would be required. The mind boggles. In zero g, this unwieldy mass of potting medium would not be terribly meaningful. Yet, the agriculture will not be accomplished in weightlessness.
The agricultural plots will have to be carefully planned and distributed about the station to prevent inordinate stresses on the station's structural 0Cmembers. In fact, with this in mind, and to lessen the amount of floor space needed for crops, the author has designed a growing frame to allow most small to medium sized vegetable crops to be stacked several high in one meter square growing trays, each tray with it's own natural light source furnished via fiber optic cabling. A sketch of this growing frame is included among the design sketches in appendix 2.
Also, much use will be made of trellises against walls of housing and office and store space for the growing of vine crops, such as squash, grapes, kiwi, cucumbers, melons, pumpkins, etc. (It isn't easy to grow melons or pumpkins on trellises, yet it can be done by a motivated and skilled gardener.) Although this will use as much square meterage, it will place far lower floor requirements on the station. It will also mean that green life will surround everyone on the station, which should both reduce the sterility of the surroundings and improve the air quality.
So, with these considerations, the requirement for square meters of floor space for crops should be diminished considerably. Given the fact that 5/6 of the row crops will have a height of 1m or less, 101,250,000m2 of row crop floor space needs to be outside of the trellis or growing frame strategems. The rest of the area requirement should be able to be met by about another 110,000,000 m2 of actual floor space. So, the area requirement of 607,500,000 m2 should shrink to about 211,250,000m2 by implementing growing frames and trellises.
The volume for the crops will be given by adding 202,500,000 m3 for potting medium, another 500,000 m3 for containers, and the amount of volume for the crops. Assuming that 1/6 of the crop volume will achieve a maximum height of 2 meters, 1/6 reaching a maximum height of 1/2 meter, 1/3 coming in at .33 0Cmeters maximum, and the last 1/3 achieving a height of no more than 1 meter, this yields a required crop volume of 67,500,000+16,875,000+22,275,000+ 67,500,000, or 174,150,000m3. The total crop volume counting potting medium, containers, and crop volume is 377,150,000 m3.
Because there will be residue and waste from the crops, assuming a crop stubble/inedible parts rate of 50%, there will be 87,075,000 m3 of material with which to deal, or 290.25 m3 per colonist. Some of this would provide raw materials for industry, particularly papermaking and dyemaking, but also- conceivably- for furniture production and a myriad of other uses which will have to be developed. The rest would go into either into mushroom production or compost which will eventually produce soil.
How much room will be necessary for the preparation and serving of food? Room is necessary not only for baking, cooking, serving, eating, and cleaning up, but also for threshing and winnowing of grains, processing of other produce-shelling, hulling, etc., storage of harvested food, milling of grains, storing of flours, growing of yeast, drying of spices, making of pastas and other specialty foods, (although much of this space could also be considered under the heading of service industries). So, the figures from the 1975 NASA Summer Study of 4 m2 (60 m3) per person for food processing and 8m2 (120 m3) for an agricultural drying area, probably aren't too bad of an estimate. That gives us and area of 3,600,000 m2 and a combined volume of required for these uses of 54,000,000 m3. Adding another 3 m2 per person for communal cooking and eating areas, yields another 900,000 m2 of space, or another 2,700,000 m3.
|Area||m2/person||total meters2||volume m3|
Having assured that the colonists will be able to eat, let's finish the area requirements so that the nuts and bolts of the design can be done.
With 6,000,000 gallons of water usage, or 22,740,000 liters, per day, the amount of volume needed for a reservoir becomes an issue. Much of the water earmarked for the growth of crops will not be recovered until the crops are eaten. Keeping a week's supply of water on the station may be overkill. Yet, it's better to err on the side of caution. Besides, extra water on the station will provide a ready source for oxygen generation and an easy way of balancing the relative humidity of the atmosphere should that percentage drop below acceptable levels. So, the design will allow for 159,180,000 liters of fresh water. This will require 1,591,800 m3. Much of this could conceivably be built into "lakes" about which recreational facilities could be centered.
The per person figures in the following table are taken from the 1975 NASA Summer Study and have been multiplied out by the projected maximum population of the station.
|Usage||area/person m2||total area m2||total volume m3|
|schools(public and private)||1.0||300,000||1,140,000|
|recreation and entertainment||1.0||300,000||900,000|
|public open space||10.0||3,000,000||150,000,000|
|Usage||area/person m2||total area m2||total volume m3|
|courts, jails, security||.50||150,000||450,000|
The total area for the station would be a minimum of 276,872,160 m2 and the station's volume at least 1,353,976,800 m3.
Having done the figures for area and volume requirements, now it remains to actually come up with a design which can be built. Immediately dismissed are the shapes dumbbell and single torus. Neither of those designs will be able to meet the design specifications for either area or volume. Spheres come to mind, as do cylinders and multiple torus arrangements. Each of these has advantages and disadvantages. Arbitarily, the design choice is a cylinder. Taking Napoleon's advice to heart, "First you engage the enemy, then you see", the design continues.
In the cylinder, the only area of the station which will be at 1g is the outer surface. As one proceeds inward, the lower the gravity will be. At the center, weightlessness will exist. Then as one would progress through the station, toward the outer surface, gravity would increase back to 1g. It is highly desirable to keep the majority of the human population in areas of 1g for the majority of their time. Plants tend to behave strangely in low gravity. So, we will need to keep most of the agricultural production in areas at either 1g or close to 1g.
There are two options for the design at this point. One, the outer shell can be made large enough so that there would be no need for decks. Everything would rest along the inside surface of the cylinder. This would be very open. It would be a large station. Two, decks or levels can be provided for. A cross section of the station would reveal concentric circles of various dimensions, all joined together with girders for support. Decking, stairs, and elevators- which will all be quite necessary under this option- were not included in the design criterion. So, to make up for that, and to provide for other items which the author may have overlooked, the station area would need to be increased to 300,000,000m2 and the volume increased to 1,600,000,000m3.
Regardless of the option chosen, to minimize the Coriolis effect, the decision has been made to rotate the colony at a speed of 1 revolution per minute (rpm), or less.
Pseudogravity of 1g must be maintained in the living areas of the station. Taken into consideration will also have to be the perceived elevation of the areas in which the colonists will live and work.
The question remains as to the height and radius of the station.
That is a question tied directly to the pseudogravity desired in
|Angular speed||radius in meters||Angular speed||radius in meters|
The actual dimensions of the station will be determined by the
design option chosen. Under option 2, the area of each deck would
be progressively less. The numbers for the required heights per
option are given as follows:
|both||option 1||option 2|
|Angular speed||height||outer area||height||total deck area|
The goal of the project is to create as "user friendly" of an
environment as may be possible. For humans to live on an obviously
curved surface would be disconcerting, at least. To determine the
observable elevation of the floor beneath the colonists, the
following formula will be used:
So chosing to do calculations for a 20m section of floor area, yields the figures contained in the following table for both options:
|Elevation with angle subtended 20 M|
|both options||option 2|
|angular speed||station radius||outer elevation||200th deck elevation||number of decks|
So, at a speed of .5, a person standing on the outer deck would notice a change in height of 5.62 cm over a 20 meter distance. That's not much. Yet, with decking, it is obvious that the perceived elevation increases dramatically as one proceeds towards the center of the station. Those increases are even more pronounced if the decks are taller.
Three meter decks will not provide enough volume for trees.
Further, the designer is of the opinion that consistent three meter
decks will add to a feeling of confinement within the station.
Therefore, the figures were redone allowing for 10M decks and .5M
deckplates, yielding the following table:
|Angular speed||Radius in meters||Height in meters||Number of decks||80th deck elevation|
As before, the elevation is computed with the angle subtended 20 M. In all cases, the floor area meets the 300,000m2 requirement. The outer elevation is, in all cases, the same as displayed in the previous table.
All of the surface area of option 1 would have pseudogravity at
or about 9.81 m/s2, or 1g. The gravity of each
successive deck on option 2 would have a decreasing gravity as
demonstrated by the following table:
|Angular speed||Deck number||Deck area||gravity m/s2||percent of 1 g present|
There are advantages and disadvantages to having decks. The advantages of having decks in the station would be that one could easily segment the station, zone it for different climatic conditions, and- if the decks were done with adequate care- each deck could have it's own atmosphere which would mean that a breach on the outer deck would not necessarily mean the end of all human life on the station. On the other hand, decking means that there would be much more complex engineering to figure stress loading. All of the weight on higher decks would eventually be transfered down to the lower decks and that could lead to stress fractures of the outer cylinder which would be disasterous. That stress loading would have to be carefully examined. The designer lacks the specific structural engineering skills to be able to do a detailed analysis. Putting in decking would also mean that the station would seem smaller, more cramped. But, it would be easier to do low gravity work in a decked station as opposed to in an open station.
There are advantages and disadvantages to having all of the station's operations be on the cylinder, apart from transport docking. It would be easier to engineer. The degree of openness would be greatly improved, rendering a sense of spaciousness. Additionally, the openness of the station means that expansion by retrofitting decks onto the cylinder would be a possibility, should station population grow beyond expectations. (The degree of difficulty in doing a retrofit should not be underestimated.) Additionally, with the radius of the station being so large, there would quite possibly be clouds and rain. Clouds will form at or above 900 m. With any of the larger radii, it is conceivable that the atmosphere would seem to have blue skies. As a practical matter, storm drains would have to be provided. Since sanitary sewers will have to be provided anyway, the engineering of storm sewers would be no major problem. Besides, a light rain would be a refreshing taste of home to the colonists.
It is the designer's decision that the station will be engineered such that most of the station's operations will rest upon the cylinder. The radius of the station will be 3559.18m. At least, that will be the interior dimension of the station. So, with allowance for infrastructure below the main surface- including maintenance access, and radiation shielding- the exterior dimensions will be substantially greater. The interior length of the station will be 12,500 m, for the sake of round figures.
Transport docking will be most easily done in low gravity. So, since the designer has a strong reluctance to open the atmosphere to space, the transport docking will be provided for by placing a ring at each of the endcaps about 800 meters in from the foci so that the gravity will be about 25% of 1g for ease of on and off loading. There must be adequate room to load and unload transports in low gravity, as well as to provide for airlocks. Elevators must be provided to take people and goods from the cylinder to the transport area and vice versa. The staging and warehousing of goods in and out can be done in racks on the cylinder.
Should low gravity areas be desired for manufacturing processes, these could be provided within the original temporary housing set up for the construction workers, or by allowing some sort of internal ships to rise up into the atmosphere towards the center of the station.
Many of these topics have been touched upon in the discussion of design criteria.
Prime in importance is the matter of radiation shielding. Most of the other designs that this designer has examined feature passive shielding in the form of meters of slag from the mining operation being placed external to the station. Aside from the sheer bulk involved, this designer finds that approach to be unacceptable. In shielding with blocks of slag, one would be required to build the shielding separate from the station. Aluminum, even aluminum and titanium, will not take the kind of stresses that rotating that much mass would entail. It would be to coin a phrase, "metal fatigue city." Yet, the one overriding problem which has disturbed this designer is that in order to have access to the station, one would have to leave gaps in the shielding. That would seem to defeat the purpose of the exercise.
This designer was particularly impressed by the patent claims of Haskell, Kipka, Stein, and Greenspan, in terms of passive systems. Haskell and Greenspan have come up with relatively low density materials which can provide adequate shielding from fission, high energy neutrons, and photons. Haskell's work provides a moldable shielding which could easily lend itself to be formed as an insulating agent within an outer and an inner deck, or even in individual homes as a second line of defense in the case of shield failure or extra intense solar flare. This sandwiched approach would have the additional advantage of protecting the station's inhabitants from bremsstahlung- secondary- radiation. The aluminum and titanium shell will emit secondary radiation when struck by particles of 300 MeV or higher energy. Yet, the shielding material will absorb this radiation, preventing it from reaching the inhabitants. Additionally, both Stein and Kipka have come up with surface treatments of grids or ridges which will prevent the free movement of radiation through a surface. Both approaches have strong merit and should be considered for incorporation into the design of SCORE.
On the mater of active shielding, Blasing et. al. have created an active filter for microwave antennae. Oxley has created an active shielding system against electromagnetic radiation coming from cell phones. Both of these are good first steps towards an active shielding system.
The matter needs further study and experimentation. Yet, the designer is absolutely convinced that a light weight passive shielding can be developed and that this system can - and should- be supplemented by an active system to cover any areas of vulnerablity in the passive system.
Once it is established that a human population will be able to live without risk of death by radiation poisoning, the next item on the agenda would be to create and maintain a breathable atmosphere and to generate and maintain a potable water supply.
Recently, the designer was heartened to hear of the discovery of water on the moon. Yet, the supply found was of insufficient volume to be directly usable on the station. However, oxygen makes up some 40% of the lunar soils, primarily bound as metal oxides. So, all of the oxygen needs for atmosphere and water generation should be able to be taken from the moon. The Clementine space probe has discovered a cache of frozen volatiles at the south pole of the moon. This may mean that we won't necessarily have to import hydrogen, nitrogen, and carbon from earth for the initial generation of atmosphere and water.
Preserving the atmospheric quality is a prime concern. Most of the balancing of the atmosphere should be able to be done by photosynthesis. However, filtration may be necessary to remove some substances. In this case, US Patent 5454848, Miller, Method of making air filtration media by intermixing coarse and fine glass fibers, issued October 3, 1995, will come in handy. Glass can easily be made on station from raw materials taken either from the moon or asteroids.
The Mao process calls for the purification of water by microbes. The process promises minimal sludge production. It's worth looking at in further detail. Possibly, it could be combined with Coate and Towles' ideas of using ozone, ultraviolet, ultrasound, magnetic fields, and filtration. Between all of these ideas, a sound waste water treatment process should be put in place.
Radiation shielding, water purification, and air purification all being taken care of, fire is perhaps the greatest enemy remaining to the colonists. Open flames are to be avoided, wherever possible. Cooking will be done via either electricity or solar generated heat. All industries will avoid open flames.
Indeed, the only justifiable use for open flames aboard the station would be related to religious observances. For a Roman Catholic, Eastern Orthodox, Lutheran, or Anglican, lit candles on the altar during the celebration of the Eucharist are meaningful. And votive, or prayer, candles are an integral part of Roman Catholic and Eastern Orthodox (and high Church Anglican) practice, as are presence candles denoting the reservation of the elements of the Eucharist. For a Jew, candles at Shabbaos eve dinner and a lit mennorah at Channuka are deeply meaningful things. Sufficient quantities of beeswax will be available to meet all these needs. But, these uses for open flames are really minimal threats to the station.
Fires can occur anywhere that there is heat, oxygen, and fuel. It will be essential that there is a network of heat sensors throughout the station. Since the station will be temperature controlled, any temperature above normal body temperature in the station will signal a warning. Exceptions to this would occur in the food preparation areas, in high temperature industries, and in the compost area. Yet, each of these areas would have their own temperature thresholds to signal danger. Should a sensor reveal an abnormal temperature, then immediate actions will be taken to investigate and eliminate any potential danger.
A reactive fire program will not suffice. SCORE must host a pro-active program of fire prevention. Regular inspections of all electrical circuits will occur to ascertain that they are safe to use. Regular inspections of all equipment which concentrates light into heat will occur for similar reasons. Any marginally defective part found will be replaced before problems can arise. Any area in which water and electricity are used in close proximity will be carefully monitored. Exothermic chemical processes will be carefully monitored.
How shall fires be extinquished? Much of the damage in small fires comes from the water used to put them out. Dry chemical extinquishers are messy to clean up after and they require recharging. Halon can cause environmental problems. Foam? Perhaps a pressurized foam delivery system built into the infrastructure of the station would be the preferable method. Bears some thought.
Now comes the major question. How will sunlight be delivered into the station? Clearly, natural sunlight is the preferred method of lighting. Most other designs have great mirrors which reflect light into a collection system. This designer doesn't like that process. Mirrors have their advantages. But, they also require a substantial breach in the shielding of the station. This designer doesn't like that idea at all.
Rather, SCORE's design incorporates a multitude of solar collectors along the exterior of the station which will channel the light into the cylinder through bundles of optical cabling. This is not an unknown process.
The optical cabling can be routed several ways to illumine the station. First, a large portion of the cabling will be routed through to whole station light dispersion units. These units could be 20m tall walls built at 100m distances where light would be dispersed from the top of the walls. But, the design doesn't allow space for that. They could be panels built into the floor to cast light upwards. They could be street lights. They could be thin panels on the sides of buildings. In none of these instances would the light dispersion be uniform or even adequate. The dispersion unit could be a central tube running the length of the station running from the foci of one endcap to the other. The outer surface of the tube would be a diffusion panel. The optical cabling would rest between this diffusion panel and an inner tube. Access to maintain the workings of this could be had from the maintenance access areas which have already been built into the systems. This option would limit the availability of low gravity areas for research and docking. But, there is no such thing as a perfect solution. The switching of this lighting will be computer controlled so that day, dusk, and night periods can be provided to different areas of the station at different times. There are some areas for which night might not be provided. The whole station cannot be asleep at the same time. Providing for the needs and security of 300,000 people will be a job without downtime. Second, fiber optic bundles will be routed to different structures: houses, industries, churches, etc. Third, fiber optic bundles will be routed to agricultural uses. Fourth, an allotment of cabling will be routed to all community kitchens.
Electrical power will be supplied by a bank of photovoltaic cells on the exterior of the station as well as by small solar energy magnetic resonance motors which will drive specific additional systems. Such motors are based on US Patent 5408167 which was issued to Gerald Shea on April 18, 1995. These motors will produce alternating current.
There are as many different ideas about how to organize the social and economic constitution of a space station as there are designers. Some suggest that this project would be a multinational venture governed by some quasi- governmental agency. Others suggest that a station be a project of a for profit corporation, run under the general structure of that corporation, with the workers at the bottom. Neither of these options particularly ensure the freedom of the individual living aboard the station.
Instead, SCORE will be a co-operative venture. This is in the best tradition of electrification. Rural Electric Co-operatives were the only way to electrify large tracts of this country. In a real way, SCORE will provide the next step forward in the supply of power through it's supply of SPS-Solar Power Satellites.
A word is in order about solar power satellites. SPS is a concept created by Peter E. Glaser in 1968. SPS are satellites in geosynchronous earth orbits. SPS are basically a solar photovoltaic array several miles across and a microwave emitting antenna. Electricity would be converted to a low density microwave beam and transmitted to earth. The beam would be received by a large antenna and and converted back to electricity at an efficiency of between 80 and 90%. All of this without any use of fossil fuels or nuclear power. It's clean, cheap, and virtually unlimited power without negative ecological effects. The potential profits should be enough to entice large numbers of investors.
Just how big will the profits be? Currently, in the designer's area of Central Illinois, electricity costs nine cents a kilowatt. Assuming that SCORE could deliver electricity to the grids at a cost of six cents a kilowatt, assuming that SCORE has only one satellite power station in orbit at one time, assuming that station generates 4 gigawatts a day, 365.25 days per year, assuming that the capital expenditures have been paid back, assuming the lack of large continuing operating expenses, the gross figures yield an annual income of $87,660,000,000. Of course, SCORE will have more than one SPS in orbit at one time. It's enough to fill the dreams of the most ardent capitalist.
Yet, SCORE will be a co-operative. There will be working and nonworking members of the co-operative. Working members will be those who are living aboard SCORE, working to make the community thrive. Nonworking members are those who invest money (buy a stake) in SCORE, but who do not live aboard the station. Profits will be distributed on a 70/30 basis, with those living aboard the station receiving the lion's share, as is only fair. It is one thing to risk money. It's another to risk one's money and one's life. That means, using the above figures that each member of the community aboard SCORE should realize, at least on paper, an annual income of $200,000 or more, depending on the degree to which the co-operative retains earnings for future expansion.
Further, SCORE will conduct it's business with fairness, honesty, and respect for members and nonmembers.
The initial working members of SCORE will be drawn from the ranks of stakeholders, and others if necessary with the provision that all adults aboard the station must be equal stakeholders in the operation. The skills needed will be listed and those persons with those skills will be examined in writing, verbally, practically as to skill- when possible- and medically. Preference will be given to families with children.
Originally, the station population will be well under the upper limit. The emphasis will be on those persons with skills needed to construct the power stations, master gardeners, and those with support skills such as cooking, security, medical skills, and sanitation. Once the station is up and operating, additional members of the community will be accepted according to potential members' skills.
The society aboard SCORE will be cashless. All working members of the co- operative will share equally in the profits of the community. Yet, these profits will be tracked electronically and distributed to the members only when the members chose to leave the community, either temporarily for a vacation or permanently. All contributions to the community will carry equal weight. A person who works constructing/ repairing satellite substructures will "earn" the same reward as a parent who chooses to care for his/her young children. Both are constructive additions to the community, and will be rewarded. The priest, minister, rabbi, or iman who cares and counsels his/her co-religionists will draw the same share as a person who works in sewage treatment. The administrator of the colony will have the same reward as a potscrubber. (By the way, that administrative position will be filled by lottery with all adult members of the community eligible and no member may serve more than one three year term as an administrator.) All activities will be recognized as contributing to society. But, destructive actions will be punishable by penalties up to loss of one's accumulated share and repatriation to Earth.
The community will furnish all necessities of life to it's own working members. Members will be expected to live lives which are productive and contribute constructively to the community. These obligations will be established by contract between the community and each member.
Children will be covered under their parents contract until they reach the age of seven. At seven, each child will be expected to make preliminary promises to the community and be entered into a pre-apprenticeship program whereby they will be exposed to the various functions in the operation of the station. This process will last until age 12 when the child will be asked to choose three areas of interest for cross training. From this time on, the child will be earning a partial share of the profits- related to his/her estimated productiveness, prorated up from 1/10 share at 12 to a full share at 23. Formal training and education will continue until the age of 23 when a child will either choose to contract with the community and become a full working member or will be released from his/her preliminary promises to the community and put on a ship for earth. At the time of the child's entry into the community as an adult member, he/she will be expected to buy a stake in SCORE. The money for this will come from the accumulated apprenticeship shares over the previous eleven years.
It is highly likely that adult members will remain on the station for a period of ten to twenty years, then retire to earth. It is also highly likely that a large waiting list of qualified applicants would rise up to fill each
Markets being what they are, with the profits being realized from SCORE being commonly known, other stations would likely be put into space, and the resulting competition for supplying power would drive down the price at which the power could be sold.
SCORE could be built with current technology. All that lacks is the will to take this bold step.
SPS would go a long ways to eliminating problems on earth caused by power generation. Acid rain would be decreased. No longer would we face the problems associated with the disposal of "spent" nuclear power plant materials. Building these solar power satellites in space would reduce their costs dramatically, making power more affordable and more available.
But, first, the commitment must be made to go forward with the establishing of the colony.
baked doughnuts oatmeal with rice milk orange juice Sausage analog scrambled tofu toast and grape jam grapefruit juice Sourdough biscuits and "sausage" gravy hash browned potatoes assorted melons Cold cereals (corn flakes, crispy rice, shredded wheat) with soy "milk" cinnamon honey buns fruit salad Bacon analog raised waffles with raspberry syrup juice Croissants cooked millet with berries Sourdough pancakes with strawberries "sausage", "bacon" or "ham" analogs Blueberry bagels cream of wheat fruit cup Fried corn meal mush with berry syrup ham analog pineapple slices Fruited danish juice Bananna bread Soy "yogurt" with fruit Rice pudding with raisins and apples Cinnamon toast Juice All with herb teas or roasted barley/chicory "coffee" LUNCHES OR DINNERS okara or tempeh burgers on wholewheat buns lettuce, tomato, onions oven fries cole slaw lemon millet pudding Lentil and rice soup spinach salad whole wheat bread peach pie stirfried vegetables with seitan and peanuts steamed rice spring rolls fresh fruit Onion soup Roasted vegetable polenta with Marinara sauce asperagus spears fresh berry sorbet Eggplant "parmesan", with rice "parmesan cheese" mache, iceplants, mizuna greens salad garlic bread poached pears Tofu hot dogs on buns five bean chili/ crackers endive salad zucchini/raisin bread Tuscan white bean stew tossed salad whole wheat rolls fresh fruit Italian "sausage" and peppers spaghetti braised fennel rolls raspberry ice "cream" Red beans and rice arugula salad with rye crackers peach shortcake "Chicken" Burritos refried beans rice melon salad Spinach lasagne with soycheese tossed salad garlic bread berry napoleon Pizza, assorted- mushroom, "pepperoni", veggie supreme, "sausage","ham" assorted raw vegetables boysenberry pie Brocolli soup "Chicken" club sandwiches Tortilla chips Lemon sorbet Vegetable soup Nine bean loaf corn on the cob rolls no bake fruitcake Greek lemon soup Baked squash with "sausage" and mushroom stuffing green peas and baby onions rolls apple crisp Dahl Chappatis Rice Assorted Chutneys "Turkey" potpie Swiss chard bread gooseberry pie Split Pea Soup/crackers "Ham" sandwiches raw cauliflower, brocolli, pepper strips pumpkin pie Potato corn chowder Vegan Sloppy Joes on buns cole slaw "cheese" cake with fruit topping Red lentil/cabbage soup Black bread raw vegetables kiwi/strawberry salad
To the NASA Ames Space Settlement Page.