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BACKGROUND: Bioregenerative life support systems (BLSS) provide self‐sufficient food ingredients to support long‐term manned missions. It is crucial to transform raw food ingredients that are regenerated in situ in BLSS into nutritional and delectable meals for spacecraft crews. It is in our interest to develop a dietary menu with Chinese characteristics that comprises biomass produced in situ with BLSS regenerated ingredients. RESULTS: Here we report an optimized Chinese 4‐day diet meal plan for 'Lunar Palace 1' that is nutritionally balanced and highly acceptable. The 2900 cal diet menu not only meets the requirements of a balanced diet for crews but also exceeds the recommended levels for most nutrients. Specifically, daily fresh food consumption in our meal plan is 1267 g day−1, of which 78% is provided by crops and insects regenerated in situ in the BLSS. The meal plan is highly favored by Chinese crews, with acceptability as high as 7.8–8.2 on a 9‐point hedonic scale. We further confirmed that our meal plan satisfies crews' basic nutritional needs through a 105‐day closed habitation experiment. CONCLUSION: In brief, the findings provide new insights for dietary meal plan design in future long‐term manned missions. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Bioregenerative life-support systems (BLSS) address interactions between organisms and their environment as an integrated system through the study of factors that regulate the pools and fluxes of materials and energy through ecological systems. As a simple model, using BLSS is very important in the investigation of element cycling and energy flux for sustainable development on Earth. A 105-day experiment with a high degree of closure was carried out in this system from February to May, 2014, with three volunteers. The results indicate that 247 g·d−1 carbon was imported into the system from stored food. Most hydrogen is circulated as water, and more than 99% H2O can be lost through leaf transpiration into the atmosphere. A total of 1.8 g·d−1 'unknown oxygen' emerged between the input and output of the plant growth module. For the urine processing module, 20.5% nitrogen was reused and 5.35 g·d−1 was put into the nutrient solution. Key Words: Bioregenerative life-support systems (BLSS)-Lunar Palace-1-Artificial ecosystem-Element cycling-Energy flux. Astrobiology 17, 78-86. [ABSTRACT FROM AUTHOR]

To conduct crewed simulation experiments of bioregenerative life support systems on the ground is a critical step for human life support in deep-space exploration. An artificial closed ecosystem named Lunar Palace 1 was built through integrating efficient higher plant cultivation, animal protein production, urine nitrogen recycling, and bioconversion of solid waste. Subsequently, a 105-day, multicrew, closed integrative bioregenerative life support systems experiment in Lunar Palace 1 was carried out from February through May 2014. The results show that environmental conditions as well as the gas balance between O2 and CO2 in the system were well maintained during the 105-day experiment. A total of 21 plant species in this system kept a harmonious coexistent relationship, and 20.5% nitrogen recovery from urine, 41% solid waste degradation, and a small amount of insect in situ production were achieved. During the 105-day experiment, oxygen and water were recycled, and 55% of the food was regenerated. Key Words: Bioregenerative life support systems (BLSS)-Space agriculture-Space life support-Waste recycle-Water recycle. Astrobiology 16, 925-936. [ABSTRACT FROM AUTHOR]

Abstract: Biologically processing rice and wheat straws into soil-like substrate (SLS) and then reusing them in plant cultivation system to achieve waste recycle is very crucially important in Bioregenerative life support system (BLSS). However, rice is a plant with strong allelopathic potential. It is not clear yet that what kinds of raw materials can be processed into proper SLS to grow rice in BLSS. Therefore, in this study, the aqueous extract of SLS made from three different materials including rice straw, wheat straw and rice–wheat straw mixture was utilized to investigate its effects on the seed germination and seedling growth of rice. The gradients of the extract concentrations (soil:water) were 1:3, 1:5, 1:9, and 1:15 with deionized water used as control. The effects of different types of SLS on seed germination and seedling vitality of rice were confirmed by analyzing the germination rate, seedling length, root length, the fresh weight and other indicants. In addition, based on the analysis towards pH, organic matter composition and other factors of the SLS as well as the chlorophyll, hormone content of rice, and the mechanism of the inhibition was speculated in order to explore the preventive methods of the phenomenon. Finally, the feasibility of cultivating rice on SLSs made from the raw materials mentioned above was evaluated and wheat raw was determined as the most appropriate material for growing rice. [Copyright &y& Elsevier]

Abstract: Vegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight. Here we developed a ground-based prototype of horn-type sequential vegetable production facility, named Horn-type Producer (HTP), which was capable of simulating the microgravity effect and the continuous cultivation of leaf–vegetables on root modules. The growth chamber of the facility had a volume of 0.12m3, characterized by a three-stage space expansion with plant growth. The planting surface of 0.154m2 was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved forward with plant growth. The total illuminated crop area of 0.567m2 was provided by a combination of red and white light emitting diodes on the internal surfaces. In tests with a 24-h photoperiod, the productivity of the HTP at 0.3kW for lettuce achieved 254.3g eatable biomass per week. Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent. Furthermore, the efficiency of the HTP, based on the Q-criterion, was 7×10−4 g2 m−3 J−1. These results show that the HTP exhibited high productivity, stable quality, and good efficiency in the process of planting lettuce, indicative of an interesting design for space vegetable production. [Copyright &y& Elsevier]

Abstract: To establish bioregenerative life support system (BLSS) on lunar or Mars bases in the future, it is necessary to firstly conduct manned simulation experiments, including several different kinds of creatures on the ground. To provide the basis for establishing the system, a multibiological life support system composed of lettuce, silkworm and algae was set up in this study. Lettuce and silkworms were cultivated in a closed integrated cultivating system (CICS) of integrative experimental system (IES). The conveyor-type cultivation method was implemented, which harvested the largest batch of lettuce and silkworms from the system and carried the smallest batch of them into the system every four days. During this process, the main element contents of lettuce were determined. Biomasses, heights, and crown diameters of lettuce in and out of the system were compared. Biomasses, excrement production rates, and bioconversion rates of silkworms in and out of the system were also studied. Results showed silkworms and lettuce in the IES could grow normally. There were no significant differences of biomass, height, or excrement production rates between creatures (lettuce and silkworms) in the system and those out of the system. [Copyright &y& Elsevier]

A bioregenerative life support system (BLSS) is an artificial closed ecosystem which provides basic human life support for long-duration and far-distance space activities such as lunar bases. “Lunar Palace 1”, an experimental facility, was constructed by our team for the integration research of the key technologies in BLSS, and then a continuous 105-day closed integrative BLSS experiment was carried out in “Lunar Palace 1”(Stage I) successfully last year. In such a system, O 2 produced by higher plants is supplied for the breathing of the crew, as well as the respiration of microorganisms which decompose the solid wastes such as inedible plant biomass and human wastes, while CO 2 produced by the crew and microorganisms is provided for plants to grow. In the system, an excessively high CO 2 level can affect plant growth and may harm human health, however, if the CO 2 level is too low, plant growth may also be inhibited. Thus, keeping the balance between CO 2 and O 2 levels is essential to the gas regulation in the system, and is one of the key points for the operation stability of the system. In this study, an efficient and controllable solid waste bio-convertor was built based on the microbial fermentation in “Lunar Palace 1”, and the CO 2 generation of the bio-convertor under the optimum fermentation conditions in the 105-day airtight experiment was monitored. Moreover, the changes of CO 2 production along with increasing or reducing the temperature of the bio-convertor from 33 to 45 °C (or from 45 to 33 °C) were also investigated, and a positive correlation between the CO 2 output and the fermentation temperature was obtained accordingly. Therefore, the CO 2 production can be adjusted effectively by changing the temperature of the bio-convertor, which implies that it is feasible to regulate the balance between the CO 2 and O 2 concentrations in BLSS by controlling the fermentation conditions of the solid waste treatment unit. The results of this study could lay a foundation for the following researches conducted in “Lunar Palace 1”. [ABSTRACT FROM AUTHOR]