A study was done to examine the possibility of acquiring water quality information on the lakes of Kanagawa Prefecture by satellite remote sensing. Water temperature and transparency, suspended solids, and chlorophyll-a concentration were examined by statistical techniques using actual measured data for lakes and Thematic Mapper (TM) data from the artificial satellite Landsat 5. Two correlation analyses were done: one among the water quality parameters, and the other between the water quality parameters and the TM data. The correlation between the TM data and each parameter of the surface water quality was high except chlorophyll-a. Therefore, the TM data allowed accurate estimation of water quality except for chlorophyll-a concentration. Data showing large differences in water quality from each lake were used to derive a linear regression expression for estimating water quality with TM data. Using this expression, estimated distribution images of water quality were made, except for chlorophyll-a concentration. The data for chlorophyll-a concentration, which is an index of water blooms showing deterioration of the lake environment, were separated into low and high, allowing a linear regression expression to be derived respectively from these data, and construction of chlorophyll-a estimation images. Our findings suggest that water quality estimation from artificial satellite data may be reliable, particularly with regard to water temperature and transparency, suspended solids and chlorophyll-a concentration.

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The Closed Ecology Experiment Facilities (CEEF) including Plantation Module, Animal Breeding & Habitation Module, Geosphere Module, Hydrosphere Module, and Material Circulation Systems has been constructed for the experiment of material circulation among plants, breeding animals, humans (crew of the CEEF), and creatures in land and ocean environments. The crew will have to do a lot of work to produce their food, and to take care of the animals and plants. When workload exceeds the crew capability, some assistants will enter into the CEEF to help them. In this case, if the assistants take O₂ from and expel CO₂ into the CEEF atmosphere, the material circulation will be disturbed to some extent. The Closed Work Suits (CWS) are to protect the material circulation in the CEEF against these disturbances caused by respiration of the assistants. The development of the CWS started in 1995, and finished in 2000. A closed circuit breathing apparatus can be used in a stand-alone mode as the basic CWS. This is easy to use, but a little of breathing gas would inevitably leak from the mask. For more accurate experiments, the integrated system of the breathing subsystem and the airtight suit is to be used, because the leaked gas from the mask is kept in the airtight suit. In the case that a wearer's metabolic heat is accumulated in the airtight suit, the cooling subsystem is needed to remove the metabolic heat. So, each of the CWS consists of three subsystems, a breathing subsystem that supplies O₂ and removes CO₂ from the breathing gas, a cooling subsystem that removes the metabolic heat from wearer's body and an airtight subsystem. The CWS must continue to perform for more than 1 hour, because it is planned that assistants will work continuously for 1 hour. Based on studies, manufacturing prototypes and man-rated experiments, characteristic requirements for the CWS have been decided. The breathing subsystem can supply O₂ and remove CO₂ at the rate of 2.7 × 10^-2 mol min^-1, and the cooling subsystem can cool down the circulation water at 300 W maximum during the CWS operation for 1 hour. The key of the development of the CWS for practical use was the weight. The weight of the functional model, that was fabricated to satisfy the characteristic requirements, was more than 51.5 kg. By redesigning the cooling subsystem, the weight of the operational model was reduced to 22.5 kg (Weight loaded on wearer's back with harness is 15.2 kg). The operational model worked well throughout all man-rated tests and the safety of the model was completely verified.

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Effect of soil temperature on the growth of Japanese white oak under the conditions of low light intensities was investigated. Trees were grown in an environment controlled chamber for 11 months at soil temperature of 8°C, 12°C, 25°C and 33°C. Soil temperature of 8°C, 12°C and 33°C was controlled by a soil temperature control system. Soil temperature of 25°C was uncontrolled. The number of leaves, area of leaves, tree height, and trunk diameter were affected by the soil temperature. Low soil temperature suppressed the enlargement of leaves under the low light intensity conditions. These results suggested the possibility of growth control of indoor plants by adjusting the soil temperature.

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This paper discusses the feasibility of the application of aeroponics (mist culture) for plant experiments in space. An aeroponics system was tested using parabolic flights where approximately 20 seconds of continuous microgravity of 0.01∼0.04 g could be simulated. The system consisted of a controlled environment root zone container, a solution tank, solution colored red, a pump with a spray nozzle, and two CCD cameras. Solution through the nozzle was sprayed on roots of Pisum sativum L. and Hordeum vulgare L. at the beginning of microgravity and the motion of solution moisture was recorded by the cameras. The moisture was held at the root surface by surface tension and did not fall during microgravity. The result indicated that aeroponics could be a potential nutrient solution delivery system for plant experiments in space.

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