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Productivities of 29 crops in the Closed Ecology Experiment Facilities (CEEF) were measured. Rice and soybean showed higher productivities than these given by the Advanced Life Support System Modeling and Analysis Project Baseline Values and Assumption Document (BVAD), but productivities of some other crops, such as potato and sweet potato, were lower. The cultivation data were utilized to develop a 1-week cycle menu for Closed Habitation Experiment. The menu met most of the nutritional requirements. Necessary cultivation area per crew was estimated to be 255 m2. Results from this study can be used to help design the future Advanced Life Support System (ALSS) including the CEEF.

CELSS technology, composed of various subsystems designed to stabilize the environment in closed space can be used to construct the Closed Ecology Experiment Facility. The Closed Ecology Experiment Facility has the character of an Environmental Time Machine. Many environmental researches of studies will, it is proposed, be conducted using this facility. The concept of Closed Ecology Experiment Facility is described, and several research items related to earth science potentially to be conducted using this facility are indicated. As an example of the application, an improved model of climate estimation is discussed.

In order to determine a required plant cultivation area which can sustain human life in a closed environment, the material circulating measurement system including a Closed-type Plant Cultivation Equipment (CPCE) in which the metabolic data of plants can be accurately measured has been constructed. According to results from cultivation experiments using rice, the harvest index was 29.9% for 110 days, and the required crop area to supply food, oxygen and water for one person was calculated to be about 111m2, 36m2 and 0.9m2, respectively.

Through the tentative lunar base construction study aiming to explore the system design method regarding closed loop life support system, the feasible system configuration including many subsystems is defined. Based upon this configuration and the estimated metabolic data of human and plants, the required material flow quantities between each subsystem in order to keep the appropriate condition for human and plants have been estimated. For promoting such fundamental researches on these subsystems and for planning the installation of test beds to check the closed loop life support function, new institute, Institute for Environmental Sciences, has been established in the end of last year.

A most important problem to creating a CELSS system to be used in space, for example, for a Lunar Base or Manned Mars mission, seems to be how to design and operate the various material recycling system to be used on the missions. Recent studies of a Lunar Base habitat have identified examples of CELSS configurations to be used for the Plant Cultivation Module. Material recycling subsystems to be installed in the Plant Cultivation Modules are proposed to consist of various sub-systems, such as dehumidifier, oxygen separation systems, catalytic wet oxidation systems, nitrogen adjusting systems, including tanks, and so on. The required performances of such various material recycling subsystems are determined based on precise metabolic data of derived from the various species of plants to be selected and investigated. The plant metabolic data, except that for wheat and potato, has not been fully collected at the present time. Therefore, much additional plant cultivation data is required to determine the performances of each material recycling subsystems introduced in Plant Cultivation Modules.

A wet oxidation method is considered to be one of the most effective methods of waste processing and recycling in CELSS (Controlled Ecological Life Support System). The first test using rabbit waste as raw material was conducted under a decomposition temperature of 280 °C for 30 minutes and an initial pure oxygen pressure of 4.9 MPa (50 kgf/cm2) before heating, and the following results were obtained. The value of COD (Chemical Oxygen Demand) was reduced 82.5 % by the wet oxidation. And also the Kjeldahl nitrogen concentration was decreased 98.8%. However, the organic carbon compound in the residual solution was almost acetic acid and ammonia was produced. In order to activate the oxidation more strongly, the second tests using catalysts such as Pd, Ru and Ru+Rh were conducted. As the results of these tests, the effectiveness of catalysts for oxidizing raw material ws shown as follows: COD and the Kjeldahl nitrogen values were drastically decreased 99.65 % and 99.88 %, respectively. Furthermore, the quantity of acetic acid and ammonia were reduced considerably. On the other hand, nitrate was showed a value 30 times as much as without catalytic oxidation.

For the Closed Ecological Life Support System (CELSS) of a manned lunar base which is planned to be built on the moon early in the 21st century, several proposed programs exist to grow vegetables inside a farming module. 1)2)3)4)5) At the 40th IAF (Malaga, 1989) the author et al presented a proposal for supplying food and nutrients to a crew of eight members, a basic concept which is based on growing four kinds of vegetables. 6) This paper describes measures for biohazard protection in farming modules. In this study, biohazard protection means prevention of the dispersion of plant diseases to other plant species or other portions of farming beds.

Much of papers describing the Lunar Base Construction have been already published. Lunar Base has been considered to be one of the very useful facilities to conduct the excellent scientific program in near future and also to develop the lunar resources such as 3 He and oxygen in order to expand the human activities in space. The scale of lunar base and the construction methods to be adopted should be determined based upon the utilization program to be conducted after the initiation of outpost habitation. In order to construct lunar base, it needs to transport lunar base elements such as habitat modules, experiment modules and so on having 20–30 tons weight and to install, connect and activate on lunar surface. The development of transportation system such as OTV enabling to transport over 30 ton payload weight from earth to moon seems to be very difficult in near future, and it seems reasonable to transport three elements per year as described in many papers already published. /1/. Therefore, the initial habitat outpost would not have enough volume to produce foods and has to have ECLS system similar to that of space station already going to be developed. After 2–3 years from the initiation of habitation, the addition of food production facilities could be started to expand the habitability of lunar base and finally the complete closed loop life support system could be installed after spending 6–7 years. This paper describes ECLS technologies to be used in the initial habitat outpost and design philosophy of the closed loop technologies to be utilized in the final stage.

The history of construction of the CEEF (the Mini-Earth), the configuration and scale of the CEEF are initially described. The effective usable areas in plant cultivation and animal holding and habitation modules and the accommodation equipment installed in each module are also explained. Mechanisms of the material circulation systems belonging to each module and subsystems in each material circulation system are introduced. Finally the results of pre-habitation experiments conducted until the year 2004 for clarifying the requirements in order to promote final closed habitation experiments are shown.

The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

New test bed facilities such as Bioplex and CEEF have been constructed to test the new advanced technologies for solving the various problems as follows, (1) how to develop air content stabilization technologies with gas balance between the generation and the absorption by living organisms, (2) how to solve the mismatching between the assimilation rate of autotrophic organisms and the respiration rate of heterotrophic organisms, (3) how to balance the speed of the waste decomposition with the absorption speed of nutrient components in the sequential plant cultivation, (4) how to develop new nutrient adjusting subsystems for each plant species, (5) how to compensate the denitrification during the waste decomposition and anaerobic microbes in the nutrient solution.

In order to study the relationship between the physiological metabolism of living things and the environmental factors such as the atmospheric contents and so on within the closed ecosystem, Closed Ecology Experiment Facilities (CEEF) were designed and now under construction based on the following concepts: (1) Individual sealed chambers (called modules) for the plant cultivation, animal breeding, human habitation and microbial waste treatment are to be constructed independently to be able to study the metabolic effects of each living thing on the environmental factors within closed ecosystem. (2) A chamber for the microbial waste treatment are to be replaced with two systems; wet oxidation reactors and chemical nitrogen fixation reactors. (3) Atmospheric control systems are to be independently attached to each module for stabilizing atmospheric contents in each module. (4) Any construction materials having the possibility to absorb oxygen and carbon dioxide are to be prohibited to use in each module for sustaining material balance. (5) Facilities have to be developed so that the closed plant and animal experiments can be done independently, as well as integrated experiments with plants and animals through exchanging foods, carbon dioxide, oxygen, condensed water and nutrient solution.

Recognizing the importance and fertility of the extra vehicular activity technologies in future space development and utilization, some related research activities have been conducted in Japan, though it has not committed itself to developing its own manned space flight capability. The purpose of this paper is to introduce and evaluate these EVA-related activities and to indicate the next step for Japan to get into the era of manned space activities including EVA in reality.

In the next century, mankind will expand its activity to the moon and Mars. At that time, humans will be exposed to a low and micro-gravity environment in long term which causes physiological and psychological problems. The authors propose an artificial gravity space station for a research laboratory on human physiology and psychology at various gravity levels. The baseline specifications and the configuration of the space station are shown. Reviewing the history of manned space flight, the necessity of the research on an artificial gravity space station is discussed, including themes of research to be conducted on the station and the application of its results. Technical issues for realization of the space station such as environmental factors, system function and assembly scenario are also discussed.

The Closed Ecology Experiment Facilities, CEEF, one of the Environmental Time Machine, is now planning to be constructed in the northern part of Japan with an eye to study the effect of atomic power industries on the local environment. This CEEF can be used not only for investigating the environmental problems related with atomic power industries but also for various environmental problems such as the habitation in lunar & Mars bases and the development of mathematical model to predict the change and change rate of earth parameters. Researches on earth environment and earth system science are discussed with use of CEEF. Preliminary experiments using a small growth chamber showed different results from those estimated by Simple Biosphere Model being used in the climate estimation.

At the 40th IAF Congress in Malaga, a nutrition system for a lunar base CELSS was presented. A lunar base with a total of eight crew members was envisaged. In this paper, four species of plants—rice, soybean, lettuce and strawberry—were introduced to the system. These plants were sufficient to satisfy fundamental nutritional needs of the crew members. The supply of nutrition from plants and the human nutritional requirements could almost be balanced. Our study revealed that the necessary plant cultivation area per crew member would be nearly 40 m 3 in the lunar base. The sources of nutrition considered in the study were energy, sugar, fat, amino acids, inorganic salt and vitamins; however, calcium, vitamin B 2 , vitamin A and sodium were found to be lacking. Therefore, a subsystem to supply these elements is of considerable value. In this paper, we report on a study for breeding snails and utilizing meat as food. Nutrients supplied from snails are shown to compensate for the abovementioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of closed ecological life support system.

In order to collect basic data about CO2 and O2 budgets of a plant cultural system in a CELSS, the variation of the CO2 absorption rates of lettuce and turnips were observed during the growing period, under different conditions. The O2 release rates were deduced from the CO2 absorption rates multiplied by 32/44. As a result, when the light intensity, the photoperiod and the atmospheric CO2 concentration increased, the rates also increased. The effects on the turnips were more significant than those on the lettuce. Turnips at 310 micromoles/m2/s of PPFD, 24 hours of photoperiod and 1100 ppm of CO2 concentration grew most actively in the present experimental conditions. One turnip absorbed 32.3 g CO2 and released 23.5 g O2 for 6 days between 24 days and 30 days after sowing.

Many agricultural and other experiments relating to the development of a Controlled Ecological Life Support System (CELSS) were proposed by scientists throughout Japan in the fall of 1982. To develop concrete experimental concepts from these proposals, the engineering feasibility of each proposal was investigated by a CELLS experiment concept study group under the support of the National Aerospace Laboratory. The conclusions of the group were described in two documents, /1/, /2/. Originally, the study group did not clearly define necessary missions leading to the goal of an operational CELSS for spaceflight. Therefore, the CELSS experiment concept study group met again to clarify the goals of CELSS and to determine three phases to achieve the goals. The resulting phases, or missions, and preliminary proposals and studies needed to develop a CELLS are described herein.

In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself was conducted. Spirulina was cultivated in the 6 liter medium containing a sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated oxygen gas was separated using a polypropyrene porous hollow fiber membrane module. Through this experiment, oxygen gas (at a concentration of more than 46 percent) at a rate of 100 to approx. 150 ml per minute could be obtained.

Many research activities regarding Controlled Ecological Life Support System (CELSS) have been conducted and continued all over the world since the 1960's and the concept of CELSS is now changing from Science Fiction to Scientific Reality. Development of CELSS technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned mars flight programs. CELSS functions can be divided into two categories, Environment Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Based on these considerations, Japanese research activities have been conducted and will be continued under the tentative guideline of CELSS research activities as shown in documents /1/, /2/. The status of the over all activities are discussed in this paper.

In CELSS (Controlled Ecological Life Support System), utilization of photosynthetic algae is an effective means for obtaining food and oxygen at the same time. We have chosen Spirulina, a blue-green alga, and have studied possibilities of algae utilization. We have developed an advanced algae cultivation system, which is able to produce algae continuously in a closed condition. Major features of the new system are as follows. (1) In order to maintain homogeneous culture conditions, the cultivator was designed so as to cause a swirl on medium circulation. (2) Oxygen gas separation and carbon dioxide supply are conducted by a newly designed membrane module. (3) Algae mass and medium are separated by a specially designed harvester. (4) Cultivation conditions, such as pH, temperature, algae growth rate, light intensity and quantity of generated oxygen gas are controlled by a computer system and the data are automatically recorded. This equipment is a primary model for ground experiments in order to obtain some design data for space use. A feasibility of algae cultivation in a closed condition is discussed on the basis of data obtained by use of this new system.