Modeling a lunar base mushroom farm.

To calculate the equivalent system mass of mushrooms, a conceptual configuration of a mushroom farm as part of a bioregenerative life support system on an inhabited lunar base was designed. The mushroom farm consists of two connected modules. Each module is a double-shell rigid pipe-in-pipe aluminum structure. The first module is used to prepare and sterilize the substrate, while the mushrooms are sown and grown in the second module. Planned productivity of the mushroom farm is 28 kg of fresh mushrooms per one process cycle lasting 66 days for 14 consumers. Mushroom production can be increased using additional modules. The calculated equivalent system masses of the mushroom farm and the mushrooms produced therein is 88,432 kg and 31,550 kg per 1 kg of dry mushrooms in one process cycle, respectively. At that, the biggest contributor to the equivalent system mass of mushrooms is the total pressurized volume of the farm - 68%. The results obtained may be a prerequisite for performing trade-off studies between different configurations of mushroom farm and calculating a space diet using the equivalent system mass of mushrooms.

The effect of supplementation of the soil-like substrate with wheat straw mineralized to different degrees on wheat productivity in closed ecosystems.

Successful incorporation of soil-like substrate (SLS) into biotechnical life support systems is often complicated by the necessity to maintain the balance between flows of mineral elements taken up from the substrate by growing plants and mineral elements added to the SLS as components of mineralized plant inedible biomass. An imbalance between these two flows can be caused by the addition of recalcitrant plant waste such as wheat straw. The purpose of this study was to determine whether the availability of essential nutrients to be taken up by the roots of the wheat plants grown on the SLS could be enhanced by supplementing the SLS with the products derived from wheat straw subjected to different levels of physicochemical mineralization in the aqueous solution of hydrogen peroxide. Different degrees of straw mineralization were achieved by using different ratios of the aqueous solution of hydrogen peroxide to straw. The study showed that supplementation of the SLS with insufficiently oxidized products of physicochemical mineralization of straw resulted in a decrease in the grain yields. The inhibitory effect of the straw subjected to physicochemical oxidation increased with a decrease in the degree to which the straw had been oxidized. Only supplementation with the straw mineralized to the highest possible degree did not inhibit plant growth and development, and the crop yield in that treatment was higher than in the other treatments.

Deep Physical-Chemical Purification of Gas Medium in Artificial Ecosystems.

The results of experiments on application of a newly developed facility for oxidation of volatile organic compounds on a platinum catalyst are presented. The feasibility of using this method in artificial ecosystems as a whole and in mass exchange of closed biological-technical life support systems in particular is shown. The possibility of deep purification of gas emitted from the reactor of physical-chemical processing of organic wastes is demonstrated. Wheat growing experiment on using the facility for oxidation of volatile organic compounds in a sealed chamber was performed. No adverse effect of probable toxic oxidation products on wheat plants during a 4-day experiment was determined.

Bioregenerative life support space diet and nutrition requirements: still seeking accord.

The capability of "dish" and "ingredient in dish" modeling to reduce the number of nutrition imbalances in bioregenerative life support diet was compared. Masses of dishes were assumed to be the independent variables in the 'dish' model, while in the 'ingredient in dish' model the independent variables were the total masses of the ingredients in a one-day menu and masses of ingredients in the dishes. The objective function in both models was minimization of discrepancy between the calculated nutrition intakes and the daily nutrition requirements of NASA for long duration space missions. Comparing of two models was carried out for the case of a one-day diet containing 12 dishes and 32 ingredients. It was established that the diet simulation by 'dish' model brings 6 nutrition imbalances. The use of the 'ingredient in dish' modeling has helped to reduce the number of nutrition imbalances to 3, namely, an excess of iron, vitamin A and saturated fat. Obstacles to the fulfillment of all nutrition requirements were the nomenclature and masses of ingredients in the dish recipes.

Incorporation of mineralized human waste and fish waste as a source of higher plant mineral nutrition in the BTLSS mass exchange.

The present study deals with the development of the principles and conditions of fish waste mineralization using the method of wet combustion with hydrogen peroxide in alternating electromagnetic field and describes testing mineralized human waste and fish waste as sources of nutrients for plants in the biotechnical human life support system (BTLSS). The study shows that mineralization of fish waste in the wet combustion reactor should be performed in the presence of readily oxidized organic matter, represented by human waste, as an activator of oxidation. Re-mineralization of the sediment in the mixture of hydrogen peroxide and nitric acid in the wet combustion reactor converts mineral elements bound in the sediment into the form available to plants. Using mineralized fish waste as an additional source of mineral elements in the nutrient solutions for growing plants based on mineralized human waste is a way to reduce the amounts of mineral elements added to the solution to replenish it, enabling fuller closure of material loops in the BTLSS.

Feasibility of incorporating all products of human waste processing into material cycling in the BTLSS.

The present study addresses the ways to increase the closure of biotechnical life support systems (BTLSS) for space applications. A promising method of organic waste processing based on "wet combustion" in hydrogen peroxide developed at the IBP SB RAS to produce fertilizers for higher plants is discussed. The method is relatively compact, energy efficient, productive, and eco-friendly. However, about 4-6 g/L of recalcitrant sediment containing such essential nutrients as Ca, Mg, P, Fe, Cu, Mn, and Zn precipitates after the initial process. These elements are unavailable to plants grown hydroponically and, thus, drop out of the cycling as dead-end products. Possible methods of dissolving that sediment have been studied. Results of experiments show that the most promising method is additional oxidation of the sediment in HNO3 + H2O2. By using the new technological process, which only involves substances synthesized inside the BTLSS material flows, more than 90% of each nutrient can be converted into the form available to plants in irrigation solutions, thus returning them into the material cycling. The results obtained in this study show the efficacy of supplementing the irrigation solutions with the mineral nutrients after sediment dissolution. Lettuce plants grown as the test object on the newly prepared irrigation solutions produced the yield that was more than twice higher than the yield produced on the nutrient solutions prepared without the sediment conversion into a soluble form. Composition of the gases emitted during this process has been analyzed. Dynamics of oxidation of the small fractions of a wax-like sediment remaining after the initial sediment dissolution in HNO3 + H2O2 in the BTLSS soil-like substrate has been studied. The entire technological scheme aimed at the full inclusion of all human wastes into the BTLSS cycling has been suggested and discussed. A process scheme of including products of human waste processing in the biotic cycle of the BTLSS is discussed in the conclusion.

Estimating CO2 gas exchange in mixed age vegetable plant communities grown on soil-like substrates for life support systems.

If soil-like substrate (SLS) is to be used in human life support systems with a high degree of mass closure, the rate of its gas exchange as a compartment for mineralization of plant biomass should be understood. The purpose of this study was to compare variations in CO2 gas exchange of vegetable plant communities grown on the soil-like substrate using a number of plant age groups, which determined the so-called conveyor interval. Two experimental plant communities were grown as plant conveyors with different conveyor intervals. The first plant community consisted of conveyors with intervals of 7 days for carrot and beet and 14 days for chufa sedge. The conveyor intervals in the second plant community were 14 days for carrot and beet and 28 days for chufa sedge. This study showed that increasing the number of age groups in the conveyor and, thus, increasing the frequency of adding plant waste to the SLS, decreased the range of variations in CO2 concentration in the "plant-soil-like substrate" system. However, the resultant CO2 gas exchange was shifted towards CO2 release to the atmosphere of the plant community with short conveyor intervals. The duration of the conveyor interval did not significantly affect productivity and mineral composition of plants grown on the SLS.

Development of human exometabolite deep mineralization method for closed ecosystems.

Methods of physicochemical further oxidation of hardly soluble sediment obtained from "wet combustion" of human exometabolites applied to space-purpose Bio Technological Life Support Systems (BTLLS) were studied. Most hardly dissoluble sediment containing Ca, P, Mg, and other essential plant nutrition elements were shown to dissolve in H2O2 and HNO3 aqueous media activated by alternating electric current. Dissolved additional mineral elements allowed (as demonstrated for lettuce) to increase the productivity of BTLLS phototrophic unit plants more than twice, which is comparable to their productivity on standard Knop solution with balanced chemical composition. Thus, dissolved mineral elements can be involved into BTLLS turnover process and increase its closure degree.

Physicochemical conversion of human exometabolites for the NaCl involvement into the mass exchange in closed life support systems.

The results of the original physicochemical method of NaCl recovery out of the mineralized human metabolites' solution obtained after their oxidation in H2O2 aqueous solution under the influence of alternating electric current are presented. The technological stages of the newly developed method are described, and its efficiency at each stage is demonstrated. The possibility to efficiency isolate Na from the NaHCO3 solution by applying electrodialysis technology and temperature separation is demonstrated. The HCl synthesis from Cl2 and H2 released during electrolysis is stable, allowing its combining with electrodialysis aimed at NaCl production under the conditions of a closed life support system.

Modeling snail breeding in a bioregenerative life support system.

The discrete-time model of snail breeding consists of two sequentially linked submodels: "Stoichiometry" and "Population". In both submodels, a snail population is split up into twelve age groups within one year of age. The first submodel is used to simulate the metabolism of a single snail in each age group via the stoichiometric equation; the second submodel is used to optimize the age structure and the size of the snail population. Daily intake of snail meat by crewmen is a guideline which specifies the population productivity. The mass exchange of the snail unit inhabited by land snails of Achatina fulica is given as an outcome of step-by-step modeling. All simulations are performed using Solver Add-In of Excel 2007.

[Ion-exchange substrate as a source of nitrogen mobile forms in the conveyor method of vegetables cultivation on artificial soil].

The investigation had the objective to evaluate the applicability of ion-exchange substrate to maintaining the mobile nitrogen content in irrigation solution and artificial coil during cultivation of a mixed (in term of age) vegetable container. Objects of the investigation were radishes and leaf cabbage crops with the period of vegetation of 28 days. A 120-day experiment showed that single introduction of the ion-exchange substrate promoted nitrogen stabilization in the irrigation solution and, consequently, yielding of higher crops as compared with the control.

[Use of the ion-exchange substrate to optimize mineral nutrition of plants within a bio-engineering life support system with a high level of closure].

Purpose of the work was to test manageability of nutrient solutions containing mineralized human exometabolites by using an ion-exchange substrate (IES) for cultivating wheat in a bio-engineering life support system with a high level of closure. Object of the investigation was wheat Triticum aestivum L. (Lysovsky cv. l. 232). Crops were raised on clayite in a growth chamber of a hydroponic conveyor system under continuous light. Correction of nutrient solution was to lift the limits of crop supply with minerals. The experimental crop grew in nutrient solution with immersed IES "BIONA-312"; nutrient solution for the control crop was corrected by adding mineral salts. Solution correction did not have a noteworthy effect on the yield, CO2-gas exchange or mineral composition of wheat plants. IES makes simple the technology of plant cultivation on solutions enriched with human exometabolites.

[Use of ion-exchange substrates for optimizing the mineral supply to plants within life support systems].

The main goal of the work is to validate ion-exchange substrates as optimizers of plant mineral supply within bio-engineering systems of life support with a high level of closure. Test objects were spring Lisovsky wheat-232 and leaf cabbage Sensuji-kyomizuna. Crops were cultivated on artificial soil (AS) in environmentally controlled plant growth chambers. Prior to seeding, AS was enriched simultaneously with wheat straw and ion-exchange substrate BIONA-312 to the extent of 2, 10 or 20% of AS dry mass. Incorporation of the ion-exchange substrate in the amount of 10% increased crop productivity and eliminated the negative effect of wheat straw. Ion-exchange substrate in amount of 20% did not yield a noticeable gain in productivity as compared with the previous test.

[Investigation of exciting light and plant leaves age effects on chlorophyll fluorescense of radish plants].

The effect of exciting light intensity and leaves age on characteristics of slow stage of chlorophyll fluorescence induction (CFI) of radish leaves has been investigated. Light dependence of the relationship of maximum fluorescence intensity in the peak P and the stationary fluorescence level (F(P)/F(S)) and also light dependence of temporal characteristics of CFI (T0.5 - half decrease of chlorophyll fluorescence intensity during slow stage of fluorescence induction and tmin - summarized CFI characteristics derived by calculating via integral proportional to variable part of illuminated in the result of chlorophyll fluorescence energy during slow stage of CFI) have been studied. Plants were grown in controlled conditions of light culture at 100 Wt/m2 of photosynthetic active radiation (PAR). It has been shown that variability of the characteristics under study, associated with the effect of leaves age, significantly decreases at exciting light intensity equal to 40 Wt/m2 of PAR and more. The lowest effect of leaves age on the value of fluorescence characteristics for T0.5 and tmin and also for F(P)/F(S) ratio was observed at the intensity of exciting fluorescence light of 60 Wt/m2 of PAR. In the researched range of light intensities the temporal characteristics of T0.5 and tmin for uneven-aged radish leaves appeared to be by an order less responsive to the intensity changes of exciting fluorescence light as compared with F(P)/F(S) ratio.

[Optimization of the mineral nutrition of plants constituting the phototrophic component of closed biological life support systems].

Applicability of a new substrate for crops cultivation in bioregenerative LSSs with a high degree of mass-exchange closure was tested. Optimization of leaf cabbage nutrition by supplementing the basic substrate fabricated of plant and animal residues with ion-exchange resins proved to have a success.

[Comparative evaluation of productivity of several green cultures as potential higher plant components of bio-regenerative systems of life support].

Purpose of the investigation was to select, analyze and evaluate green plant species known for assisting resistance to diseases and improving physiological functions in humans, and to test allelopathic compatibility of selected species with basic systems for life support. Nutrient substrates were freshly made soil-like substrate (SLS) and clayite. Green cultures were 6 spinach species, 2 lettuces, 2 leaf cabbage species and ruccola. The investigations showed that plant productivity was either equal to or better on freshly made SLS than on clayite; however, the greens accumulated large quantities of nitrate nitrogen. The highest productivity distinguished leaf cabbage; the best antiradical properties was demonstrated by lettuces and the worst, by some spinach species. None of the species displayed a negative allelopathic effect on productivity of the reddish test culture.

[Possible ways to include human exometabolites in the turnover of biological life support system].

Purpose of the investigation was to study feasibility to include solid and liquid human discharges in the turnover of bioregenerative life support systems for physical/chemical and biological treatment. Human exometabolites were mineralized by way of wet process in hydrogen peroxide in alternating electromagnetic field. The resultant solutions were used to water plants cultivated on a soil-like substrate or haydite. Given that urea as a source of nitrogen for BLSS is undesirable, in one of the experiments mineralization was followed by enzymatic urea decomposition with soybean flour urease. The experiments showed no difference in the productivity of plants cultivated on a standard mineral medium and with the use of mineralized exometabolites.