Controlled Ecological Life Support System Research Articles

Anaerobic membrane bioreactor for hygiene wastewater treatment in controlled ecological life support systems: Degradation of surfactants and microbial community succession

The treatment and reuse of hygiene wastewater is crucial to “close the loop” in the controlled ecological life support system (CELSS), and to guarantee longer space missions or planetary habitation. In this work, anaerobic membrane bioreactor (AnMBR) was applied for hygiene wastewater treatment, focused on surfactant degradation and microbial community succession. The removal efficiency of COD and surfactants was 90%∼97% and 80% with a urine source-separation strategy. The microbial community gradually shifted from methanogens to sulfur-metabolizing and surfactant-degradation bacteria, such as Aeromonas. Sulfate was a surfactant degradation product, which triggered sulfate reduction and methane inhibition. The activated carbohydrate and sulfur metabolism were the key mechanism of the microbial process for the excellent performance of AnMBR. This study analyzed the degradation mechanism from the perspective of microbial mechanism, offers a solution for CELSS hygiene wastewater treatment, and supports the future improvement and refinement of AnMBR technology.

Application of functional microbial agent in aerobic composting of wheat straw for waste recycling

Controlled Ecological Life Support System (CELSS) is a closed artificial ecosystem which can regenerate oxygen, food, water and other substances for crew survival in long-term space missions. Solid organic waste is a vital resource pool for material reuse and recycling in CELSS. In this study, solid wastes including wheat straw and food waste were disposed via aerobic composting under functional microbial agent inoculation. Compared to tests with a commercial microbial agent addition and without exogenous microorganisms, system performance was promoted by the self-developed microbial agent significantly which exhibited the highest composting temperature (67.4 ± 1.5 °C) and longest thermophilic period (7 days). And treatment with self-developed microbial agent showed the highest values in volatile solid reduction, C/N reduction, germination index (124.83 ± 13.25%) and total available nutrient content (47.45 ± 1.69 g/kg), which suggested the feasibility of compost product to be used for crop cultivation. Moreover, shifts of microbial community in phylum and genus levels were observed. Microbial agent augmentation led to high quality and safe compost product after a short composting period (30 days) without leaching, which suggested an efficient way to promote the recycling and recovery of solid waste in CELSS.

The Feasibility Research on Reusing High Salinity Wastewater as a Plant Nutrient Medium for Plant Hydroponics in CELSS

The reuse of wastewater is a key problem in controlled ecological life support system (CELSS). In this study, the feasibility to reuse the treated wastewater (including sanitary wastewater and urine wastewater) as a plant hydroponic medium was verified. Two salt-tolerant plants, apium graveolens Linn (celery) and mesembryanthemum cordifolium L.F. (cordifolium), were cultivated with the reused medium or Hoagland nutrient solution, and the characteristics of crop growth, hydroponic medium composition, and elements absorption by plants were investigated. The results showed that the reused medium replenished with micronutrient elements could maintain the normal growth of cordifolium and celery crops. The biomass productivity of cordifolium cultivated by the recycled medium (121.53 g FW/strain) was higher than that cultivated by Hoagland nutrient solution (98.33 g FW/strain). The nutrient elements accumulation in plant dry mass indicated that plants could effectively utilize the recycled mineral elements in wastewater, and cordifolium exhibited better stability and adaptability to salt-induced environment. The absorption capacity of Na and Cl elements in cordifolium cultivated within the reused medium was the highest, which was 4.54% DW and 2.63% DW, respectively. This study demonstrated the feasibility to directly reuse domestic wastewater as the main ingredient for plant hydroponics, which could provide insights into design and operation of plant hydroponics system and water circulation system in CELSS.

Design and establishment of a large-scale controlled ecological life-support system integrated experimental platform

A Controlled Ecological Life-Support System (CELSS) can meet the demands of food, oxygen, and water for human, as well as providing psychological benefits during deep space exploration by the continuous materials regeneration. Many key techniques of the platform are needed to explore before applying to the extraterrestrial planets. In this study, a large-scale CELSS integrated experimental platform was designed and constructed to meet the basic life-support material demands of six crew members (max). The platform was composed of four kinds of cabins including Crew Cabin (CC), Plant Cabin (PC), Life-Support Cabin (LSC), Resource Recycling Cabin (RRC) and affiliated facilities. Eight cabins were involved in the platform, i.e., CCs I and II, PCs I, II, III and IV, LSC, and RRC. The platform involved 15 subsystems and covered a plant culture area of 206.6 m2 (a max extensible area of 260 m2) and a total volume of 1340 m3. The joint debuggings and the 4-subject 180-day CELSS integration experiment were carried out successfully. The material closures were 55% (on average) for food (70.8% in highly efficient production period), 100% for atmospheric regeneration, 100% for water regeneration, and 87.7% for recycled solid waste in the 4-subject 180-day integration experiment. It verified that the indicators of the platform meet the technical requirements and realize food regeneration, air regeneration and water regeneration through the integration of physico-chemical technique and biological technique for the long-term survivals of six crew members in the closed cabins.

Light Spectral Composition Influences Structural and Eco-Physiological Traits of Solanum lycopersicum L. cv. ‘Microtom’ in Response to High-LET Ionizing Radiation

This study evaluated if specific light quality (LQ) regimes (white fluorescent, FL; full-spectrum, FS; red-blue, RB) during plant growth modified morphological and photosynthetic traits of Solanum lycopersicum L. ‘Microtom’ plants irradiated at the dry seed stage with 25 Gy 48Ca ions (IR). The irradiation reduced plant size while it increased leaf dry matter content (LDMC) and relative water content (RWC) compared to the control. FS and RB light regimes determined a decrease of plant height and a rise of RWC compared to FL plants. The irradiation under FS and RB regimes favoured the development of dwarf plants and improved the leaf water status. Under the FL regime, irradiated plants showed reduced photosynthesis and stomatal conductance. The opposite behavior was observed in RB irradiated plants in which gas exchanges were significantly stimulated. RB regime enhanced Rubisco expression in irradiated plants also inducing anatomical and functional adjustments (i.e., increase of leaf thickness and incidence of intercellular spaces). Finally, 48Ca ions did not prevent fruit ripening and the achievement of the ‘seed-to seed’ cycle, irrespective of the LQ regime. Overall, the present study evidenced that RB light regime was the most effective in optimising growth and photosynthetic efficiency of ‘Microtom’ irradiated plants. These outcomes may help to develop proper cultivation protocols for the growth of dwarf tomato in Controlled Ecological Life Support Systems (CELSS).

Operation overview of a biological waste treatment system during the 4-crew 180-day integrated experiment in the controlled ecological life support system (CELSS)

Waste management and treatment is vital to health care and material circulation, especially in the Controlled Ecological Life Support System (CELSS) with finite resources for long-duration manned space missions. A closed ecological-cycle integrated 4-crew 180-day experiment platform was established to investigate the key technologies such as effective cultivation of higher plant, water treatment and recycling, waste management and treatment. In this study, generated waste during the integrated experiment was classified as renewable and non-renewable waste. The renewable waste including all crew feces and part of inedible plant biomass were treated in a biological system where the aerobic composting technology was utilized. The performance in relation to degradation effect, phytotoxicity and nutrient evaluation was examined during the continuous 180 days. The long-term operation results displayed that 96.26 kg feces and 74.4 kg wheat straw were treated, and 90.6 kg compost product was discharged in nine batches. The microbial community variation was analyzed and Firmicutes, Actinobacteria and Proteobacteria enriched in the compost. The phytotoxicity of compost was examined by seed germination index (GI) and GI of Chinese cabbage ranged from 88% to 132% for all batches. Compared to grown in vermiculite only, the lettuce yield increased 19% when grown in a mixture of vermiculite and processed compost. The summary of this work will be helpful to facilitate future applications of aerobic composting technology as the bio-based waste treatment technology in CELSS.

BIOPROSPEK MIKROALGA DI PESISIR MUARA PUTAT PULAU LOMBOK

Aquatic biodiversity in Muara Putat Estuary, Lombok Utara Regency, Lombok Island is the result of nutrient enrichment in the coastal. A complex combination of natural factors that support the growth of barriers in mangrove plants, agricultural and plantations, fish and aquatic invertebrates that regulate during the summer and rainy seasons. As a source of knowledge, biodiversity of aquatic microalgae is a major producer of nutrient chains in the estuary, habitat diversity will affect the source and regulation of aquatic nutrition. Studying microalgae is one of the important tools to determine the condition of an estuary and microalgae bioprospecting in the future. This study aims to determine the prospect of microalgae species found in Muara Putat waters during the summer and rainy season as well as to record the types of local microalgae found in these waters. Water samples are collected at 3 stations covering upstream, middle, and downstream estuary. Measures were carried out on the value of environmental supporting factors such as pH, water temperature, salinity, brightness, and currents. Obtained two local species that dominated the Bacillariophyceae and Chlorophyceae classes, with both of bioprospects that were sufficiently able to act as bio-indicators of aquatic saprobity, biochemical characteristics with various contents, could be as an agent of the Controlled Ecological Life Support System (CELSS), and produces certain metabolites based on changes in aquatic nutrient concentrations.

Wheat Cultivation and Nutrient Control for the 180-day CELSS Integrated Experiment

This research aimed to select the well-adapted wheat cultivar and to explore an optimum nutrient control pattern for wheat cultivation in the 180-day integrated experiment of controlled ecological life support system (CELSS). In the experiment, six wheat cultivars from different areas of China were preselected and cultivated in four separate recirculating hydroponic systems (HySy), nutrients in which could be controlled and recycled according the values of pH, electrical conductivity (EC) and dissolved oxygen (DO). Wheat covered an area of 111.3 m2 and had been planted in 17 batches with a 15-day time interval to realize stable regeneration of oxygen, water and food during the 180-day duration in the closed cabin. The results indicated that different cultivars displayed different adaptabilities to the controlled environment. Wt04 had a stronger adaptability with the highest yield (12.82 g DM m−2 d−1) and edible radiation use efficiency (RUE) (0.28 g DM mol−1) whereas Wt06 adapted this environment poorly because of its excessive vegetative growth. For the morphological characters, wheat plants tended to dwarf in the CELSS environment compared with the field. An innovative controlling pattern was established for nutrient supplement. Through the real-time monitoring of pH, EC and DO of the nutrient solution and the periodical detection of the contents of nutrient elements, the nutrient solution could be controlled and recycled continuously without being renewed under a suitable state for wheat plants growth during the 180-day integrated experiment.

Recovery of monovalent mineral salts from urine in controlled ecological life support system by nanofiltration: Feasibility study

In controlled ecological life support system (CELSS), the water, oxygen, food and other life-support materials should be provided through material closure and circulation. Monovalent mineral salts were one kind of essential life-support substances for astronaut. However, few studies were focus on their recovery in CELSS. In this study, nanofiltration (NF) was used to investigate the feasibility of separating and recovering monovalent mineral salts from urine in CELSS by two membranes of DL and NF3. Results showed that the DL had higher flux and better monovalent ion separation efficiency (both the Scation and Sanion were lower) than the NF3. The organics in NF permeate was mainly urea which could be hydrolyzed into NH4+-N in natural. Under operation pressure of 8 bar, cross-flow velocity of 0.8 m/s, pH of 6.0, volume reduction factor (VRF) of 4.0 and through storing for 72 h, the monovalent ions could be separated effectively with multivalent ions and organics. The main component of the solid part in the product solution were Na+, K+, and Cl−, which accounted for 26.32%, 18.00% and 49.96%, respectively. The results of this study suggested that recovery of mineral salt of NaCl and KCl from urine in CELSS by nanofiltration was feasible.

Simulated manned Mars exploration: effects of dietary and diurnal cycle variations on the gut microbiome of crew members in a controlled ecological life support system.

BackgroundChanges in gut microbiome are closely related to dietary and environment variations, and diurnal circle interventions impact on human metabolism and the microbiome. Changes in human gut microbiome and serum biochemical parameters during long-term isolation in a controlled ecological life support system (CELSS) are of great significance for maintaining the health of crewmembers. The Green Star 180 project performed an integrated study involving a four-person, 180-day duration assessment in a CELSS, during which variations in gut microbiome and the concentration of serum 25-hydroxyvitamin D, α-tocopherol, retinol and folic acid from the crewmembers were determined.ResultsEnergy intake and body mass index decreased during the experiment. A trade-off between Firmicutes and Bacteroidetes during the study period was observed. Dynamic variations in the two dominant genus Bacteroides and Prevotella indicated a variation of enterotypes. Both the evenness and richness of the fecal microbiome decreased during the isolation in the CELSS. Transition of diurnal circle from Earth to Mars increased the abundance of Fusobacteria phylum and decreased alpha diversity of the fecal microbiome. The levels of serum 25-hydroxyvitamin D in the CELSS were significantly lower than those outside the CELSS.ConclusionsThe unique isolation process in the CELSS led to a loss of alpha diversity and a transition of enterotypes between Bacteroides and Prevotella. Attention should therefore be paid to the transition of the diurnal circle and its effects on the gut microbiome during manned Mars explorations. In particular, serum 25-hydroxyvitamin D levels require monitoring under artificial light environments and during long-term space flight. Large-scale studies are required to further consolidate our findings.

Effects of a new-type inner-canopy illuminant and light quality on spring wheat growth in CELSS

Traditional plant illumination in Controlled Ecological Life Support System (CELSS) has been generally roof illumination (RI). In order to improve the utilization efficiency of light energy for cultivating plants, a new-type inner-canopy illuminant (ICI), which was embedded among the stems and leaves of spring wheat, was applied in the research. The experimental group was 50% ICI+ 50% RI, while the control group was 100% RI, both of which consumed the same total electric power. For each of the two groups, six different qualities of light were separately used to study the effects of red, blue and green light under simulated CELSS conditions. By comparing the two groups, it was found that the PPFD (Photosynthetic Photon Flux Density) on the leaf surface was increased in the experimental group, resulting in a shortened growth period, higher net photosynthetic rate (Pn), lower plant height, larger leaf area index (LAI), higher biomass and seed yield. The increased percent of PPFD across the leaf surface under the experimental group on average reached 8.6%–14.6% within 30 days, while PPFD increased by 3.9%–8.0% in 70 days after sowing. An increased seed yield as large as 19.6% per day was achieved in the experimental group. In addition, Red, blue and green light contributed differently to photosynthetic efficiency. Firstly, red light promoted the shortening of growth period, while blue and green light had no significant effect on it. For example, reducing 20% red light caused a 12- or 13-day prolongation of the growth period. Secondly, increasing the ratio of red/blue could increase Pn, plant height, leaf area index, total biomass and seed yield. Thirdly, it can be seen that the green light did not contribute to photosynthesis directly, but it still had an important role in spring wheat growth. Green light significantly increased the tiller number and LAI, as well as total biomass and seed yield, but daily seed yield was not increased under 10% or more green light. The total seed yield was the highest in combination of 80% red +10% blue +10% green light, but the highest daily seed yield was achieved under 90% red +10% blue light for a shorter growth period. The above results should provide a useful reference for choosing the suitable plant lighting method in CELSS.

Growth and biomass yield of 25 crops in the 4-subject 180-day integrated experiment

To support human life during deep space exploration, the cultivation of higher plant plays a critical role in sustaining gas, water, and nutrient cycles in Controlled Ecological Life Support System (CELSS). This study aimed to develop crop co-cultivation and highly efficient production techniques, explore diverse plant growth patterns, and evaluate the capability of continuous production in a long-term closed environment. Twenty-five crops, including 1 grain, 2 tubers, 2 oil plants, 2 fruits, 3 functional plants, and 15 vegetables, were selected for their nutrient content, growth cycle, and environmental requirement. Depending on their requirements of light source, photoperiod, nutrient solution, and temperature, 25 crops were distributed in 4 separate cabins, which spanned 195.36 square meters in total. Most wheat were grown in a nutrient solution, whereas a small portion of wheat and the other crops were grown in a solid substrate, in order to recycle solution and solid wastes properly. Throughout the trial period, most of these crops adapted to the closed environment and completed the whole growth and development cycle normally. The results showed that the crop cultivation system could continuously provide a variety of vegetables and fruits at a rate of 1.43 kg d−1 (fresh weight) for 4 crews in the 180-day experiment and at a rate of 1.30 kg d−1 (dry weight) grains and tubers in the last 60 days. The harvest index of sweet potato was higher than that of wheat and potato, whereas its yield per unit area was similar to that of wheat. Since the harvest of the first batch of grains and tubers, crops grown in the cabins gradually became the main source of crews' diet. In addition, various cultivars displayed distinct differences in growth and yield under the same conditions. Further research in crop cultivation in CELSS should focus on the adaptability and adaptation mechanisms of the cultivated varieties.

Multi-System Adaptation to Confinement During the 180-Day Controlled Ecological Life Support System (CELSS) Experiment.

Confinement experiments are essential to prepare long-term space exploration. The 180-day Chinese CELSS (Controlled Ecological Life Support System) study is unique in its design, including a closed-loop system and mid-mission simulation of Mars-like day–night cycle of 24 h 40 min for 36 days (days 72–108). Our aim was to study physiological and psychological consequences of this confinement in four healthy volunteers (one female). CELSS platform consisted of six interconnected modules including four greenhouses. Life support systems were controlled automatically. Body composition, fluid compartments, metabolic state, heart, large vessels, endothelial function, and muscle tone were studied using biological, functional, and/or morphological measurements. Behavioral activities were studied by ethological monitoring; psychological state was assessed by questionnaires. Body weight decreased by ∼2 kg mostly due to lean mass loss. Plasma volume and volume-regulating hormones were mostly stable. Carotid intima-media thickness (IMT) increased by 10–15%. Endothelium-dependent vasodilation decreased. Masseter tone increased by 6–14% suggesting stress, whereas paravertebral muscle tone diminished by 10 ± 6%. Behavioral flow reflecting global activity decreased 1.5- to 2-fold after the first month. Psychological questionnaires revealed decrease in hostility and negative emotions but increase in emotional adaptation suggesting boredom and monotony. One subject was clearly different with lower fitness, higher levels of stress and anxiety, and somatic signs as back pain, peak in masseter tone, increased blood cortisol and C-reactive protein. Comparison of CELSS experiment with Mars500 confinement program suggests the need for countermeasures to prevent increased IMT and endothelial deconditioning. Daily activity in greenhouse could act as countermeasure against psycho-physiological deconditioning.

Photosynthetic response of Scenedesmus quadricauda to carbon ions irradiation

Plants and algae are one of the key components in Controlled Ecological Life Support System (CELSS) in long-term manned space exploration. However, the biological effects of high linear energy transfer (LET) cosmic radiation on algae are even less well characterized. The photosynthetic apparatus is one of the most sensitive targets after radiation. In this study we analyzed the chlorophyll fluorescent parameters (Fv/Fm, φPSII, and NPQ), the photoprotective pigment lutein, and the transcriptional expression of Lhcb1 and Lhcb2 in a green microalgae, Scenedesmus quadricauda after exposure to 12C6+ ions that were provided by the Heavy- Ion Research Facility in Lanzhou (HIRFL), China. Scenedesmus quadricauda has rapid growth rate and is rich in high-value products which are essential for CELSS development. The results showed that low photosynthetic efficiency of Scenedesmus quadricauda was found in the 60 Gy group within 2 h after radiation. The thermal dissipation abilities of Scenedesmus quadricauda were stronger after exposure to 20 Gy and 60 Gy group within 2 h. Meanwhile, the transcriptional expressions of Lhcb1 and Lhcb2 were up-regulated after exposure to 20 Gy of carbon ions within 4 h. Therefore, 20 Gy of carbon ions radiation could cause stimulative effects on the photoprotective ability and transcriptional regulation of the major LHCII antenna proteins in Scenedesmus quadricauda. Our findings provide the first insight into the biological effects involved in heavy ions radiation on the photosynthetic activity of Scenedesmus quadricauda.

Water management in a controlled ecological life support system during a 4-person-180-day integrated experiment: Configuration and performance

Water management subsystem (WMS) is a major component of the controlled ecological life support system (CELSS). For guaranteeing the water requirement of crop growth and crewmember's daily life, a WMS was established in a 4 person 180-day integrated experiment (carried out in Shenzhen, China, 2016) to maintain a closed cycle with a total water amount of ~23 m3. The design and operation of the WMS was summarized as follows: (1) Collection and allocation of condensate water. About 917 L/d condensate water (>98% was from plants' evapotranspiration) was collected, and ~866 L/d of which was reused as plant nutrient solution after ultraviolet (UV) disinfection, and 50.6 L/d was used as the raw water for the domestic water supply module (DWS). (2) Domestic water supply. The condensate water from the plant cabin was purified through the DWS, a modified membrane bioreactor (MBR) system, and then provided hygiene and potable water to 4 crewmembers with different water quality standards. (3) Wastewater recovery. 51.4 L/d wastewater from urination and personal hygiene were treated together via a biological wastewater treatment process to complete the conversion of nitrogen and organic matters, and then recycled to plant nutrient solution. (4) Nutrient solution recycling. In the overall water cycle process, the plant nutrient solution was continuously self-circulated and the water quality of which was maintained at a relatively stable level with total organic carbon of 20–30 mg/L and NH4+-N < 1.0 mg/L. The 180-day continuous operation demonstrated that a 100% water closure was achieved. Based on the results of this study, an upgraded water cycle system for larger-scale and longer-term CELSS has been proposed.

Development of a combined anaerobic and aerobic membrane bioreactor for wastewater treatment and reclamation in terrestrial-based controlled ecological life support system

Abstract A novel wastewater treatment and reuse system (WTRS) combining an anaerobic membrane bioreactor (AnMBR) and an aerobic membrane bioreactor (MBR) with the design capacity of 115 L/d was developed for a terrestrial-based controlled ecological life support system (CELSS). Results clearly showed that the WTRS realized mineralization of organic compounds and reservation of nitrogenous nutrient, therefore converting the effluent into replenishment for the hydroponic system. Trace gas emission from the WTRS could meet requirements for the whole CELSS. Compared with physico-chemical processes, the specific consumables consumption of the WTRS was advantageous but its specific energy consumption is still in need of improvement. Results of microbial community analysis were consistent with the running state of the AnMBR and the MBR.

Enhancement of surfactant biodegradation with an anaerobic membrane bioreactor by introducing microaeration

In controlled ecological life support system (CELSS), 100% water recycle efficiency is needed. Both water and nutrients in wastewater needs reclaiming. In an anaerobic membrane bioreactor (AnMBR) designed to hydrolyze organic matters and convert organic nitrogen, accumulation of anionic surfactants and organic compounds was observed in the supernatant. To solve the problem, microaeration which had rarely been reported to enhance surfactants biodegradation in anaerobic process was introduced and it was proved to be an effective approach that resulted in concentrations of surfactants and soluble chemical oxygen demand (SCOD) in the supernatant decreasing from 9000 mg/L and 40000 mg/L to 2000 mg/L and 10000 mg/L, respectively. And the degradations followed the kinetic characteristics of zero order reaction with R2 values of 0.9472 and 0.949. Three-dimensional excitation emission matrix (3D-EEM) analysis revealed that some activities of microbes were activated and enhanced by microaeration, which resulted in the disintegration of aggregates of large molecules, indicated by the size exclusion chromatography (SEC). After the introduction of microaeration, the emerging genera Aquamicrobium, Flaviflexus, Pseudomonas and Thiopseudomonas in the microbial community might be responsible for the effective biodegradation of the surfactants.

A modified MBR system with post advanced purification for domestic water supply system in 180-day CELSS: Construction, pollutant removal and water allocation

Water supply was vital to people's life, especially inside Controlled Ecological Life Support System (CELSS) for long-term space exploration. A platform of 4-person-180-day integrated experiment inside a CELSS including 6 cabins called ‘SPACEnter’ was established in Shenzhen, China. Based on this platform, a Membrane Bio-Reactor (MBR) system configuring post advanced purification, including I-MBR, II-MBR, nanofiltration (NF), reverse osmosis (RO), ion-exchange (IE), polyiodide disinfection (PI) and mineralization (MC) stages, used as a Domestic Water Supply System (DWSS) to guarantee crew's daily life was constructed. The performance of DWSS to treat the real plant cabin's condensate water was examined during continuously 180-day experiment. The long-term operation results showed that, though the influent pollutant load changed as the experiment processing, the system exhibited stable performance on pollutants removal with average effluent TOC＜0.5 mg/L, NH4+-N＜0.02 mg/L, NO3−-N＜0.25 mg/L, NO2−-N＜0.001 mg/L, and displayed good capacity for controlling the trace metal ions and microorganism. The effluent through such modified MBR system was sufficiently allocated as hygiene water and potable water, and the average value was 39.69 and 10.93 L/d, respectively. The consumption of the modified MBR process was within the designed allowable scope. The outcomes of this study will be helpful for facilitating future applications of MBR as bio-based water supply technology in the CELSS.

Cellular immunity monitoring in long-duration spaceflights based on an automatic miniature flow cytometer

Monitoring cellular immunity is essential for long-duration spaceflight missions. To address this need, we developed an automatic miniature flow cytometer that is targeted to monitor the cellular immune function of astronauts or passengers during long-duration spaceflights. Automatic sample preparation, a disposable sheathless focusing chip, optical self-alignment, and side scatter (SSC) detection capability were developed to meet the strict requirements of spaceflight applications. SSC and four colors of fluorescence are measured to realize lymphocyte subsets counted from whole blood. This technology was used in four-subject 180-day controlled ecological life support system (CELSS) experiments to monitor the cellular immunity of four crewmembers by counting the lymphocyte subsets (total CD3+, CD3+CD4+, and CD3+CD8+ cells). The microgravity compatibility was successfully verified on a parabolic flight. Thus, the presented system was proven a feasible solution for health care applications during long-duration manned spaceflight.

Non-methane hydrocarbons in a controlled ecological life support system

Non-methane hydrocarbons (NMHCs) are vital to people's health and plants' growth, especially inside a controlled ecological life support system (CELSS) built for long-term space explorations. In this study, we measured 54 kinds of NMHCs to study their changing trends in concentration levels during a 4-person-180-day integrated experiment inside a CELSS with four cabins for plants growing and other two cabins for human daily activities and resources management. During the experiment, the total mixing ratio of measured NMHCs was 423 ± 283 ppbv at the first day and it approached 2961 ± 323 ppbv ultimately. Ethane and propane were the most abundant alkanes and their mixing ratios kept growing from 27.5 ± 19.4 and 31.0 ± 33.6 ppbv to 2423 ± 449 ppbv and 290 ± 10 ppbv in the end. For alkenes, ethylene and isoprene presented continuously fluctuating states during the experimental period with average mixing ratios of 30.4 ± 19.3 ppbv, 7.4 ± 5.8 ppbv. For aromatic hydrocarbons, the total mixing ratios of benzene, toluene, ethylbenzene and xylenes declined from 48.0 ± 44 ppbv initially to 3.8 ± 1.1 ppbv ultimately. Biomass burning, sewage treatment, construction materials and plants all contributed to NMHCs inside CELSS. In conclusion, the results demonstrate the changing trends of NMHCs in a long-term closed ecological environment's atmosphere which provides valuable information for both the atmosphere management of CELSS and the exploration of interactions between humans and the total environment.