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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.

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.

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.

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 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.

The closed ecology experiment facility (CEEF) has a small positive pressure control system consisting of rubber buffers and a mechanical subsystem. In the present study, effects of small temperature disturbances caused by changes of surrounding conditions on the pressure control system are investigated experimentally and in numerical simulations. Though solar radiation causes a pressure disturbance in the facility, choosing the proper diameter of ducts which connect the rubber buffers to the modules, the rubber buffers can follow fluctuations of low frequency, like daily atmospheric fluctuations and pressure changes caused by temperature control of the facility’s air conditioners, and can cut off those of high frequency due to changes of environmental conditions.

A mathematical model was developed in order to predict quantities of CO2 and O2 gas exchange, transpiration, biomass production, food production and nutrient absorption by candidate crops in Closed Ecology Experiment Facilities (CEEF) in which material recycling in a controlled ecological life support system (CELSS) is to be made. This model includes effects of physical parameters such as light intensity, air temperature, humidity and atmospheric CO2 concentration on these processes and plant aging effect on these processes. Using results from experiments in which candidate crops were grown under controlled environment and data from literature, mathematical models for each crop was given physiological parameters. Then, changes in biomass and food accumulation, gas exchange and transpiration of each crop with time were calculated.

IES (Institute for Environmental Sciences) is now constructing CEEF at Rokkasho, Aomori, Japan. The simulation for material flow is made based on a system model of CEEF, which includes one person and 7 plant species of Rice, Soybean, Komatsuna, Sesame, Tomato, Potato and Buckwheat. In this simulation software, plants, human and their support systems are mathematically defined and material flows such as O2, N2, CO2, waters, fertilizers and organic matters are computed. This software simulates only material flow and but does not simulate thermal dynamics of the environment. The simulation result showed reasonable material flows in a closed system.

The simulation test for the controlled ecological life support system is planned by Institute for Environmental Sciences (IES) of Japan. The purpose of this test is to confirm that in the closed space, the environmental and life support system is normally carried out. The establishments to perform the simulation test has been constructed at Rokkasho-mura village, Aomori prefecture, in Japan. We have been developed “Oxygen Recovery System” which decompose carbon dioxide (CO2) and regenerate oxygen(O2), for the simulation test. The oxygen recovery system consists of a equipment to reduce CO2 using the Sabatier method and a equipment to regenerate oxygen using water electrolysis method (Refer to Figure 1). And this reaction principle is as follows; The carbon dioxide is produced by the respiration of human, animals and plants. The carbon dioxide is reduced to methane and water using hydrogen in the first reaction.

The system design of the Nitrogen Fixation System (NFS) for CEEF has been carried out. The system is a fertilizer production process for plant cultivation from air and water. Newly developed technologies are adopted as key processes of the system. Use of physico-chemical methods made the total system compact, energy efficient and controllable. The NFS is completely self-confined and generating no unnecessary byproducts. The system has a applicability for future lunar or Mars base CELSS system.

In the closed environments such as manned space station, it is necessary to remove contaminant gas to keep a suitable environment. Removal of gaseous contaminants generated from crew, animals, and plants is important function to keep the environment below the allowable level in the Closed Ecology Experiment Facilities (abbreviated as CEEF). CEEF consist of three modules for habitat, animal and plant, the supporting facilities for each module and a plant cultivation facility. CEEF are scheduled to be constructed from 1994 in Aomori Prefecture, northern part of Japan. For designing Trace Contaminant Control Assembly (TCCA) for CEEF, the following six (6) trace contaminants have been selected as major contaminant gas in CEEF; Ammonia (NH3) Methane (CH4) Ethylene (C2H4) Carbon Monoxide (CO) Nitrogen Dioxide (NO2) Sulfur Dioxide (SO2) Ethylene is well-known as an aggressive contaminant to plant growth and maturity.