#36 June 1990
Section 220.127.116.11.036.of the Artemis Data Book
© David A. Dunlop
Executive Director: Lunar National Agricultural Experiment Corporation - LUNAX
The development of a 3000 to 5000 person community such as “Prinzton” [the award winning entry of the Lunar Reclamation Society in the 1989 NSS Space Habitat Design Competition] will only be cost feasible within a 25 to 50 year time frame, if it feeds itself AND dependent Cislunar and low Earth orbit (LEO) populations. Doing this will leverage the economic advantage of abundant lunar oxygen which can provide half the mass of all plant and animal tissues and 8/9ths of the mass of the associated water. Foreseeable cost per pound, Earth surface to LEO and to Cislunar and lunar surface locations, require such a “grow your own” strategy to save the unnecessary import cost of this oxygen content. Importing such high-oxygen content items as food and water to the Moon would be like bringing “coals to Newcastle”.
The substantial savings (circa 95%) in fuel costs of similar payloads launched from the Moon over those launched from the surface of the much more massive Earth, will give lunar-grown food, and water constituted with lunar oxygen, a 48% and 73% price advantage respectively, delivered to LEO and other Cislunar space facilities. While this estimate discounts the high capital costs of accessing lunar resources, such costs can be amortized at a rate low enough to maintain most of this profit potential.
Prinzton facility design criteria should favor the “low tech” approach of requiring the use of ample plant biomass to recycle carbon dioxide to fresh breathable oxygen and to otherwise “condition” the atmosphere inside the settlement. Indoor pollution, already a concern in contemporary terrestrial buildings using synthetic construction materials, will be a critical issue in a permanently enclosed biosphere which is essentially a closed system or at least one which has highly limited output leakage and input make-up in comparison to facilities of any size within Earth’s biosphere.
Vegetation will also likely provide the “low tech” water filtration and purification for the closed-cycle hydrosphere envisioned, with pure water recovered by dehumidifiers from plant transpiration to supply drinking water at the “start’ of the loop.
The evolution of lunar habitat design will require a transition from the initial “carry out and bring back” strategy of shuttle missions, space stations like Mir and Freedom, and early lunar surface habitats, to one which introduces a sustainable largely closed-system biotechnology. The ultimate significance of this transition recognizes that life itself will begin to transform the human-habitable environment just as life has transformed Earth. Indeed, the design myopia most likely to prevail in our “Prinzton” scenario is the continuing focus on human requirements in the narrow sense of air, water, and nutritional needs.
The scale of Prinzton’s ambitions for a large human population demands a recog nition that the “best” biosphere for humans is also the most diversified; “best” here defined as the most stable, self-sustaining and diverse community of life forms possible. The physical security of any large colony will require food stocks which are diversified and not subject to catastrophic mono-crop failures. While the Moon is close enough to quickly resupply food stocks or to evacuate in the event of a “potato famine” type of bio-catastrophy, a Mars base would be highly vulnerable given the 26-month launch window spacing and long transit times.
Early high priorities for base development will be the creation of lunar soils from the raw material of the regolith, human wastes, and wastes from food production and processing. The micro-ecology of creating a growing soil bank for sustainable agricultural production will require planned early storage of biological wastes for their ultimate transformation into viable soils. Frozen storage in the lunar “shade” of lava tubes or high latitude rille and crater walls should initially be adequate. This process of storage and accumulation cannot continue indefinitely, however. These wastes will necessarily become the organic feedstocks of the new biosphere.
The capital equipment investment needed for this transformation of waste stock can be kept in bounds by employing the “M.U.S./C.L.E.” lunar industrialization strategy of Massive, Unitary, Simple type elements that can be locally self-manufactured, married to Complex, Lightweight, Electronic type elements that must be imported from Earth. Such a strategy minimizes the import burden needed to sustain the growing settlement, an incurred debt which has to be paid for with income-earning exports.
First, a sealed atmosphere, a temperature-controlled, humidity-controlled, and light-controlled environment with considerable volume, will be needed. Prior experimentation with the development of viable lunar soils from lunar regolith simulant and biowastes will have shown whether a lunar soil micro-ecology can develop from these waste sources and whether or what additional seed stocks of specialized soil bacteria will be needed.
A prototype trial of this sort might be conducted in a near-sterile Antarctic environment, such as one of the “Dry Valleys” near the main U.S. base at McMurdo Sound, to gain engineering experience in conditioning cold soil-sheltered volumes into air-tight biospheres; and to validate the expected heating and lighting requirements, ingress/egress provisions, etc. ‘Regolith’ pulverized from Antarctic rock and gravel and the accumulated biowastes from nearby Antarctic bases would provide the basic ingredients for creating viable soils.
Because many of the international participants in Antarctic research are also spacefaring nations, the creation of a simulated lunar (or Martian) biosphere in such a location could provide an interesting collaboration precedent. it would also supply economic data on both construction costs and logistic requirements as well as on the design requirements for storing and recycling the biological wastes generated by such bases. Because the “trashing” of the Antarctic environment is already apparent even with the relatively limited human intrusion there, this engineering prototype of a more eco-sensitive system will serve not only lunar habitat goals but also provide a transition to an environmental ethic requiring such Arctic or Antarctic bases TO LIVE DOWNWIND AND DOWNSTREAM OF THEMSELVES, something that settlers in the closed biospheres of the space frontier must do.
The difference between such polar prototype research sites and such potential sites as lunar lava tubes or rille-bottom enclosures is still considerable. Possibly some differences between Earth rock soils and lunar regolith, and certainly the available water and atmosphere, will make an Arctic or Antarctic experiment much simpler and far less costly. However, construction techniques at these temperatures, experience with equipment design, and the logistic experience with working bases and their crews in the collection, storage and development of suitable soils for sustainable agriculture would be much superior to reliance on blank sheet paper exercises alone. The failures experienced by such a prototype biosphere could literally save the billions of dollars that would be wasted if serious design flaws are uncovered only after lunar failures occur. An Antarctic prototype installation would thus be sound risk management.
The selection of the type of biome(s) (ecosystem regions such as tropical forest, prairie, desert, etc.) initially to be developed will also require closed system prototypes prior to any significant expansion of a lunar base. The strategy of Biosphere II at Oracle, Arizona in developing several diverse biomes in close proximity, appears to this writer to be a ‘high stakes’ gamble that homeostasis can be achieved and developed with a hybrid of existing natural biomes. A more conservative approach setting up just a temperate or tropical climate agricultural biome with an already known ecosystem of plants, animals, and insects, would seem to be a more simple initial step with a higher chance of stability.
The numeric modeling of each species’ consumption, excretion, and impact on the other species sharing the biome, would enable the development of whatever fall-back chemical and/or mechanical component may be needed to insure full-cycle balances within lunar biospheres. A species data bank, appropriate monitoring technology, computer software, and operations experience, all need to be accumulated to develop confidence and sophistication in running a sustainable biosphere. This systems engineering problem is highly complicated and will require greater computing power to track the complex interactions between what will inevitably become hundreds, then thousands of species. The strategy of developing a replication of existing natural biomes and modeling them numerically should occur well before investment can be risked in a lunar application. Critical species serving as indicators of biospheric function (a miner’s canary) must be identified.
Because Biosphere II in Arizona is essentially a proprietary enterprise, an independent critique of its outputs, systems engineering, and management techniques is not likely to be generally available. This knowledge product may initially be affordable only to governments able to purchase this technology base. I am of the opinion that additional sealed biosphere prototypes both significantly smaller in scale than Biosphere II, and considerably larger, will be needed to give confidence in the reliability of the biotechnology involved. This will need to follow a developmental progression from relatively simple and small biospheres to larger and more complex ones.
The outfitting of small Shuttle External Tank biosphere modules for initial lunar basing might progress to intact lava tubes. Such a tube could be sectioned off and sealed with needed environmental controls of the similarly much larger scale of the Prinzton arcology of villages, horticultural and agricultural areas, and production facilities.
Economics will not be the only primary rational for biosphere development. Perhaps more importantly in the long run, the psychological comfort and stability of the human population will be critical. The stark beauty of the lunar landscape is unlikely to wear well on the human psyche. The “softened” environment created by plant and animal life will be an essential element of human expansion onto the Moon and elsewhere off Earth. The “Garden of Eden” which mankind is rapidly destroying on Earth, will of necessity need to be reconstructed on the Moon. And tending this “garden” will be a major focus of human efforts there.
The type of high tech environment so familiar in space habitation scenarios usually have an overwhelming industrial character to them, emphasizing machinery, rockets, mining equipment, and power generation equipment, etc. Prinzton’s interior should more probably evoke a “hanging gardens” ambience than that of a[n aircraft] “hanger”.
The very propensity of life to intrude into all areas of its ecosphere will no doubt produce many unforeseen and unforeseeable problems of maintenance and equipment failure. Vacuum seals, for example, should be designed of materials that do not serve well as dinner for anaerobic bacteria or other denizens of microbial reality.
The tenacious battles for species dominance in biosphere eco-niches are dynamic balances that must be carefully observed and monitored. These tasks of bio-maintenance and monitoring will initially be labor-intensive. The ratio of settlement population devoted to biotechnology including growing food, harvesting, packing, storing, preparation, and general bio-maintenance and monitoring will likely comprise 25%-50% of personnel responsibilities. Thus the character of the settlement will be as much dominated by agriculture as by the other industries such as mining, oxygen-, metal-, glass-, and ceramic-production, transportation, and research and development efforts etc.
The cost-per-pound economics of importing anything up out of Earth’s deep gravity well dictate an inevitable reliance on lunar-grown food stuffs just as they do for lunar-sourced fuel and building products. The cure of off-planet population growth will, for the next century or more, be more limited by lunar agricultural capacity than by other technology constraints. Neither Earth-based or Mars-based agriculture are likely to have economic significance outside their own respective gravity wells. Large scale sustainable biosphere construction in the asteroid belt will be possible only toward the end of this hundred year time frame given the probable stress on Martian and lunar development during that interval. - MMM
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