Search

The Closed Geosphere Experiment Facility (CGEF), which is highly airtight, is designed to facilitate the investigation of carbon cycles of terrestrial ecosystems. The Geosphere Module has 5.8 m×8.7 m ground area and 11.9 m average height, including 3.1 m soil depth. A wetland ecosystem, with Phragmites australis-dominated vegetation, is scheduled to be introduced into the Geosphere Module. This study characterizes the distribution and variation of the environmental factors of the Geosphere Module (air temperature, light intensity, and air CO2 concentration) that influence the carbon cycles of ecosystems before introducing the wetland ecosystem into the Module. The CGEF can control the average air temperature within 1°C of a set value. The Geosphere Module has heterogeneous light intensity, which decreases from south to north ranged from 54% to 79%. However, the heterogeneity of light conditions caused no serious problem for the growth of P. australis as shown by a pot test over two years. The CO2 separation capacity was sufficient for driving carbon circulation in the Geosphere Module under a condition of maximum CO2 flux from ecosystem respiration of P. australis-dominated vegetation including soils during the night. The initial performance tests showed that CGEF can serve as an experimental means for analyzing ecosystem processes on carbon cycles under controlled conditions.

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.

The two haloacetate dehalogenase genes, dehH1 and dehH2 , on the 65-kb plasmid pUO1 from Delftia acidovorans strain B were found to be located on transposable elements. The dehH2 gene was carried on an 8.9-kb class I composite transposon (Tn Had1 ) that was flanked by two directly repeated copies of IS 1071 , IS 1071 L and IS 1071 R. The dehH1 gene was also flanked by IS 1071 L and a truncated version of IS 1071 (IS 1071 N). Tn Had1 , dehH1 , and IS 1071 N were located on a 15.6-kb class II transposon (Tn Had2 ) whose terminal inverted repeats and res site showed high homology with those of the Tn 21 -related transposons. Tn Had2 was defective in transposition because of its lacking the transposase and resolvase genes. Tn Had2 could transpose when the Tn 21 -encoded transposase and resolvase were supplied in trans . These results demonstrated that Tn Had2 is a defective Tn 21 -related transposon carrying another class I catabolic transposon.

It is necessary to develop a small positive pressure control system for the closed ecology experiment facilities because of the needs to prevent contamination from the atmosphere and to protect against over differential pressure loading. In the present study, a numerical analysis method was developed to calculate the quantity of state of the closed module which is fitted with rubber buffers for the small positive pressure control system. Experiments to examine the pressure change of the closed module caused by rapid temperature control of an air conditioner were carried out at Biosphere-J. Comparison of calculated and experimental results showed that the present dynamic simulation is suited to estimating the quantity of state of the closed module.

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.

宇宙での運用状況を想定し, その第1段階として, CELSS用水再生循環システム構成の検討および装置の開発・運転試験を行い, 以下の知見を得た.1) CELSS用水再生循環装置を試作し, その運転操作状況などからみて, 設計どおりの運転制御が行われたが, 耐久性の面では装置上改善すべき必要性が認められた.2) 加熱蒸発および運転実験より, 本人工尿では, 60%以上の水の回収は困難であることが明らかになった.3) 用水処理性能低下を招く析出物は, 主としてリン酸とカルシウム, マグネシウムによる化合物であることが判明した.4) RO膜の本供試水での除去率は, 公称除去率と比べ, 20～80%低いことが認められた.とくにアンモニアは除去率が低く, その後のTPVでも処理が難しいので対策が必要と考えられた.

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.

Many papers describing the lunar base construction have been published previously. Lunar base has been considered to be a useful facility to conduct future scientific programs and to get new nuclear energy resource, namely 3He, for defending the environmental collapse on Earth and also to develop lunar resources such as oxygen and nitrogen for extending human activities in space more economically. The scale of the lunar base and the construction methods adopted are determined by the scenario of a lunar utilization program but constrained by the availability of the established space transportation technologies. As indicated in the scenarios described in papers regarding lunar base construction, the first steps of lunar missions are the investigation of lunar itself for conducting scientific research and for surveying the lunar base construction sites, the second steps are the outpost construction for conducting man-tended missions, for more precise scientific research and studying the lunar base construction methods, and third steps are the construction of a permanent base and the expansion of this lunar base for exploiting lunar resources. The missions within the first and second steps are all possible using the ferry (OTV) similar to the service and command modules of Apollo Spacecraft because all necessary weights to be landed on the lunar surface for these missions seem to be under the equivalent weight of the Apollo Lunar Lander. On the other hand, the permanent facilities constructed on the lunar surface in the third step requires larger quantities of construction materials to be transported from Earth, and a new ferry (advanced OTV) having higher transportation ability, at least above 6 times, compared with Apollo Service and Command Modules, are to be developed. The largest problems in the permament lunar base construction are related to the food production facilities, 30–40 m2 plant cultivation area per person are required for providing the nutrition requirement and the necessary electric power per person for producing high energy foods, such as wheat, rice and potato, are now estimated ranging from 30 to 40 kW. The extension program of crew numbers under the limitation of usable transportation capability anticipated at present and the construction scenarios, including the numbers of facilities to be constructed every year, are to be determined based upon the requirements of plant cultivation area and of electric power for producing necessary and sufficient foods in order to accelerate the feasibility studies of each subsystem to be installed in the permanent lunar base in future.

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.