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The Closed Ecology Experiment Facilities (CEEF) were installed to collect data for estimation of transfer of radionuclides from atmosphere to humans in the ecosystem. The first target among the radio-nuclides is 14C. In order to validate function of material circulation in an experimental system constructed in the CEEF, circulation of air constituents, water and materials in waste was demonstrated connecting the Closed Plant Experiment Facility (CPEF) and the Closed Animal and Human habitation Experiment Facility (CAHEF) of the CEEF, since 2005 to 2007. The CPEF has a Plant Cultivation Module (PCM), which comprises of three plant chambers illuminated solely by artificial lighting, one plant chamber illuminated by both natural and artificial lighting, a space for preparation, and an airlock, and a physical/chemical material circulation system.

The CEEF (Closed Ecology Experiment Facilities) was constructed for collecting data on carbon transfer from the atmosphere to crops, livestock and humans by conducting material circulation experiments, including the habitation of humans and animals and growing crops which supply food and feed, within a closed environment. The main objective of the CEEF project involves understanding the transfer of radiocarbon in the environment via experiments using stable carbon isotopes. On the other hand, the project is also a good example demonstrating human life in ecosystem material circulation. Many people visited and toured the CEEF and the project has been introduced by the media. The candidate inhabitants, who were selected for the project following medical and psychological testing, are called “eco-nauts”. The CEEF project was introduced and eco-nauts participated in events with the intention of educating the public on the human impacts on an ecosystem made by a science museum.

Closure experiments will be conducted using the Closed Plant Experiment Facility (CPEF) and the Closed Animal and Habitation Experiment Facility (CAHEF) of the Closed Ecology Experiment Facilities (CEEF). The CEEF behavioral Prediction System (CPS) has been developed to check the CEEF operation for the closure experiments in advance. For the development of CPS, a simulation program for CPEF had been developed and reported. A simulation program for CAHEF was developed, and combined with the simulation program for CPEF. This integrated simulation program was validated by data obtained from a habitation experiment conducted in CEEF.

The Closed Ecology Experimental Facilities (CEEF), is designed to simulate material circulation, and is an artificial closed agricultural ecosystem with plants, humans and animals. The first seven-day air circulated confinement experiments using the CEEF were conducted three times. The experiments included psychological monitoring of two crew members named “Eco-nauts”. Even though there was some trouble with the CEEF regarding the atmospheric gases (which one of the Eco-nauts discovered himself), all three experiments were completed without critical problems and both Eco-nauts maintained a stable psychological status. Through the experiments, it was found that the interior environment of the CEEF could fluctuate within short time periods, and that frequent monitoring by the instantaneous and sensitive Face Scale Test allowed scoring of the Eco-nauts' response to such fluctuations.

A linear programming model has been constructed to develop a cultivation plan for habitation experiments using a two-person crew in Closed Ecological Experiment Facilities (CEEF), which is an earth based integration demonstration test bed of Advanced Life Support System (ALSS), under constraints such as a limited cultivation area and various nutritional requirements. The optimized area was 129.14 m2. According to the results, the optimized cultivation plan was then implemented in a habitation experiment in the CEEF during FY2004 with some modification to meet requirements from menu formulation. Results of the cultivation experiment, also during FY2004, showed feasibility of the plantation plan in the view point of nutrition supply, though errors between expected and observed productivities varied from −37 % to +267 %.

This paper introduces a concept and a design to supply paper products for an earth based Advanced Life Support System (ALSS) test bed and it shows some results of paper production trials on the ALSS using inedible biomass. Rice plants (i.e. straw and roots), and soybean stems were pulped by boiling and/or alkali soaking and a mechanical processing method. Paper could be produced from both and exhibited different characteristics. Paper with quality suitable for hygienic tissue could be obtained and very absorbent paper was also possible. A rapid pulping method without a chemical process was also investigated. A potential for reducing chemical consumption, liquid waste and labor cost of paper production in the ALSS was demonstrated.

Closed habitation experiments are to be carried out using Closed Ecology Experiment Facilities (CEEF) from 2005 to 2009. The last target of duration of closed habitation is four months. Preliminary study and testing have been conducted in order to start the closed habitation experiments. In 2004 as the last year of the preliminary test phase for the 2005–2009 experiments, periodical harvesting from staggered cultivation of 23 crops including rice, soybean, peanut, and sugar beet was continued during 103 days. In order to balance with metabolisms of humans (named as “eco-nauts”) and animals, it is necessary to stabilize production of edible and inedible biomass, CO2 uptake and O2 production of crops. Although biomass production decreased rapidly during first five weeks of the 103-day period, it was relatively stable during last ten weeks. Average major foodstuffs in the harvested edible biomass met the requirement of two Eco-nauts although several minor ingredients were insufficient.

Preliminary seven-day habitation experiments without complete closure of the habitation module were performed in the Closed Ecology Experiment Facilities (CEEF) to obtain information for the closed habitation and to prepare for the actual closed habitation experiments to be launched in September 2005. Energy requirements have been estimated for habitant candidates in closed habitation experiments (to be called Eco-nauts). This paper presents the calculations of Eco-nauts' energy requirements using records of life activities during the preliminary experiments and compares them with the expected energy supply from the CEEF.

The Closed Ecological Experimental Facilities (CEEF), designed to simulate material circulation, is an artificial closed agricultural ecosystem with plants, humans and animals. In the experiments starting from FY2005, habitants referred to as eco-nauts will be exposed to complex workloads and various CEEF environmental factors, which may influence their physio-psychological state, and lower their performance. Therefore, preliminary experiments were conducted on the workload-matched (11.1h work, 168h, airlock open) and the environment-matched condition (6.9h work, 24h, air circulation) to monitor physio-psychological changes. As a result, both experiment types were conducted as scheduled without any major problems, and no serious physio-psychological disorders were observed in the eco-nauts. One week closed habitation experiments will be performed as a preliminary step toward much longer (max. 4 months) experiments.

Closed habitation experiments are to be carried out using Closed Ecology Experiment Facilities (CEEF) from FY2005 to FY2009. The last target of duration of closed habitation is four months. Preliminary study and testing have been conducted in order to carry out the closed habitation experiments. The CEEF has three closed plantation chambers (PC-A, B and C) with artificial lighting solely having each cultivation area of 30 m2 and a closed plantation chamber (PC-F) with both natural lighting and supplemental artificial lighting having a 60-m2 cultivation area. A ‘stable’ period of sequential crop cultivation was maintained for four weeks in a trial experiment conducted in FY2003 using the Plantation Module (PM), in which rice, soybean and crops including rice sapling, soybean sapling, soybean, peanuts and safflower were cultivated in PC-A, PC-B, PC-C and PC-F, respectively. Amount of total clean water input to PM was 741 L day−1 on the average for the period.

Rating of daily amounts of CO2 and O2 exchange of crops, animals and humans to be involved in the long-term habitation experiments using the Closed Ecology Experiment Facilities (CEEF) were carried out. Daily amounts of the CO2-absorption and O2-generation of crops including rice, soybeans and other 27 vegetables were estimated from data obtained from a sequential crop cultivation experiment conducted from August to December of FY2001. Daily amounts of O2-consumption and CO2-expiration of two female Shiba goats to be involved were estimated based on gas exchange determination conducted in FY2002. Daily amounts of CO2-expiration and O2-consumption of two persons to be involved were estimated based on correlation between respiration rate and heart rate, heart rate data during the simulated habitation in the CEEF and a tentative work schedule.

In the Closed Ecology Experiment Facilities (CEEF), with integrating the Closed Plantation Experiment Facilities (CPEF) and the Closed Animal Breading & Habitation Facilities (CABHF), closed habitation experiments without material exchange with the outside will be conducted after the 2005 fiscal year. Cultivation experiments of about 30 crops and the integrating test of the material circulation system required for the closed habitation experiments have been performed since 2000 fiscal year. Using data reported in these experiments, material circulation in CEEF is simulated based on the recent operation strategy, and the storage capacity needed for the buffer of an air processing subsystem was estimated. In order for two humans to dwell over 120 days, the storage capacities of the carbon dioxide tank, the oxygen tank, and the waste gas tank in CPEF, and the carbon dioxide tank and the oxygen tank in CABHF are 820 g, 2830 g, 4425 g, 1780 g, and 1792 g, respectively.

For validation of operation schedules for the Closed Ecology Experiment Facilities (CEEF), development of the CEEF behavioral prediction system (CPS) has been started. The CPS will be simulated using the CEEF operation schedule. The CPS will gather data on quantities of materials in each component of the CEEF and operational status of each component at the start of the simulation, and configure them as the initial conditions of the simulation. For requirements of experiments, the simulation program for the CPS should be easy to adapt for changes of components and object materials. Because the CEEF is a nonlinear system, available period of the simulation is important. A flexible algorithm for the changes was developed. The simulation was available for three days to validate.

The plant system plays roles of edible biomass production, O2 production, CO2 removal, and so on, in bioregenerative life support systems. In order to simulate the edible and inedible biomass production and gas exchange of crops, it is necessary to construct reliable dynamic prediction models for each crop considering not only short-term environmental effects but also its long-term effects, because response of plant system is highly dependent on plant age, plant size, and environmental condition experienced by the plant. Closed Plantation Experiment Facility (CPEF) of Closed Ecology Experiment Facilities (CEEF) has three plantation chambers with artificial lighting system, which has maximum capability for providing PPFD of approximately 1900 μmol·m-2·s-1 for crops at canopy top level in these chambers. Each even-aged population of rice and soybean was grown in each plantation chamber.

A simulation of an open mode system experiment was run using the same experimental conditions as an integration test conducted from September 1999 to February 2000 using the Closed Plant Experiment Facility at the Institute for Environmental Sciences in order to evaluate the operation of closed mode system to be conducted in future. Operation of the open mode system experiment required a supply of water and carbon dioxide from the outside, and the discharge of nutrient waste water and oxygen. The present simulation verified the feasibility of using non-integrated wet-oxidation processor, nutrient synthesis unit and nutrient waste water processor connected within a closed mode system, and it was confirmed that sufficient material circulation could be achieved when rice and soybeans were divided into six beds with different growing stages to facilitate control of the nutrient solution.

The Closed Ecology Experiment Facilities (CEEF) can be used as a test bed for Controlled Ecological Life Support Systems (CELSS), because technologies developed for the CEEF system facilitate self-sufficient material circulation. Two experiments were conducted from September 27, 1999 to February 17, 2000 and from September 28, 2000 to February 9, 2001 in this study. In both experiments, rice and soybeans were cultivated sequentially in each chamber, having a cultivation bed area of 30 m2 and floor area of 43 m2, inside the Plantation Module (PM) with artificial lighting of the CEEF. 6 to 8 other vegetables were also cultivated in a chamber, having a cultivation bed area of 60 m2 and floor area of 65 m2, inside the PM with natural lighting in the first experiment and the second experiment. In both experiments, stable transplant and harvest of each crop were maintained during approximately one month, after approximately 3-months preparatory cultivation.

The basal metabolism of the Candidate Animal is mainly on energy metabolism that was estimated for future animal breeding in CEEF as preliminary research. The amounts of gas exchange in the respiration and heat production of the Shiba goat (native Japanese goat) were analyzed to predict energy and material flow of the animal breeding system in the Closed Ecology Experiment Facilities (CEEF). Experimental animals were fed Timothy hay or inedible parts of rice cultivated in CEEF. The feces and urine were collected during the 7-day metabolism measurement period after a 2-week preliminary breeding period. The O2 consumption, CO2 production, and CH4 production were measured by a mass spectrometric respiration gas analysis system on the 7th day of the metabolism measurement period. Heat production was also obtained from these data. O2 consumption, CO2 production and CH4 production were 100.3 - 153.8 L, 127.2 - 174.0 L and 5.7 - 10.8 L per day (at 0°C, 0.101MPa), respectively.

Simulation of material circulation for a closed experiment using CEEF consisting of a plant and human system was performed. Initial set of materials contained in CEEF was decided by a decision procedure. Before the closure where the plant system is operated independently, the plant system (CPEF) needs gas exchange of O2 and CO2 with the outside. After the closure where the plant and human system are operated in a cooperation mode with mutual material exchange, no exchange of materials is needed. The closure time corresponds to the longest cultivation period to be cultivated in CPEF.

In the Closed Ecology Experiment Facilities (CEEF), waste materials such as plant inedible parts, feces and urine of animal and human, and garbage are to be decomposed to inorganic materials by a physical and chemical (P/C) process; Wet Oxidation (W/O). It is known that significant part of nitrogen (N) in the waste materials is reduced to gaseous nitrogen (N2) through W/O process. There is also some deposition of minerals such as iron (Fe) and phosphorous (P) through W/O process. Nitrogen Fixation Subsystem (NFS) produces ammonia (NH3) which is one of end products of NFS, from N2 separated from module air and hydrogen (H2) derived from electrolyses of water, and also produces nitrate (HNO3) from a part of the NH3 and oxygen (O2) derived from electrolyses of water. As another end product of NFS, ammonium nitrate (NH4NO3) is produced from the HNO3 and a part of the NH3.

As a part of CEEF, a hydro-sphere experiment system has been installed in the air-tight hydro-sphere chamber built in fiscal 1997. Environmental factors in the chamber such as air composition, temperature and humidity could be fully controlled from 360 to 2000ppmCO2, from 20 to 30°C and 70%RH respectively using air composite adjusting system and air-conditioner. In this chamber having 640m3, three aquariums having 20m3 volume each have been installed. One of those aquarium will be used for the sea water buffer, the other two will be used for breeding living organisms such as small animals and macro-algae. A water reclamation system also has been installed in addition to those aquariums, and sea water is to be circulated at the rate of 20m3/3days between those aquariums and this reclamation system in order to realize the simulated sea water eco-system. The water reclamation system is composed of a membrane filter and bio-filter.