Performances of light sources, a halogen lamp, a fluorescent lamp and light emitting diodes (LEDs), commonly used for plant culture were examined under altered gravity conditions created during parabolic airplane flights. The surface temperatures of the light sources, irradiances, photosynthetic photon flux densities (PPFDs) and spectral distributions of radiation from the light sources were measured at the gravity levels of 0.01, 1.0 and 1.8 G for 20 s each during parabolic airplane flights. As a result, the surface temperature of the halogen lamp bulb increased most rapidly and the irradiance increased most remarkably among the three light sources at 0.01 G. On the contrary, the surface temperatures and light intensities of LEDs were most stable followed by the florescent lamp with gravity change. These characteristics of LEDs would be suitable for plant experiments and plant culture in space.

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The Sabatier reaction catalyzed by titania-supported ruthenium (Ru/TiO2) was investigated for the aim of practical water (H2O) generation from reduction of carbon dioxide (CO2) with hydrogen (H2) at lower temperatures. Various Ru/TiO2 catalysts in powder form were prepared by a dry processing named “barrel-sputtering”. Hydrogenation of CO2 to methane successfully proceeded on the catalysts at temperatures below 300°C without the formation of carbon monoxide (CO) even if pretreatment of the catalysts was carried out. It is noteworthy that catalytic activity of Ru/TiO2 catalyst was enhanced when the catalyst was immobilized in a three-dimensional structure. In addition, use of the immobilized catalysts resulted in significant alleviation of not only catalyst weight but also temperature differences in the reactor.

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We developed a CO2 removal device as a part of life-sustaining devices in ISS. We measured CO2 discharge rate and CO2 concentration in discharge gas from adsorption/desorption beds including zeolite 5A with aspect ratios (bed length L/ diameter D) of 0.5, 3.9 and 8.5. The discharge rate had two peaks caused by flow of remained air among zeolite pellets and desorption of CO2 from the zeolite during heating and evacuation. The CO2 concentration in the discharge gas was independent from the aspect ratio. The upper limit of bed length Li was found to be 0.32m to avoid the effect of the pressure gradient in the longitudinal direction, which reduces the obtained CO2 recovery efficiency. The adsorption band length Za and its moving velocity VZa increased from 0.20 to 1.31 m and from 2.1 x 10-3 to 1.4 x 10-2 m/min with decreasing bed diameter, respectively. The optimum bed length L is between taVZa (ta: adsorption time) and Li to obtain the highest CO2 recovery efficiency. The optimum combination of D and L is 0.3 and 0.32m, respectively, for minimization of diameter.

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In March 2005, the Japan Aerospace Exploration Agency (JAXA) announced the JAXA Vision, and formed an internal working group for Environment Control and Life Support (ECLS) systems to prepare for future human space missions. This paper shows the status of a study of the CO2/Trace Gas Contaminant Remover for the Human Space Transportation System (HSTS) that was performed in 2010 by the ECLS working group.

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Caves and lava tubes have been discovered at several areas based on remote sensing data and orbital imagery. Caves and other underground spaces moderate extreme temperatures - cooler in daytime and warmer at night. Early man used such spaces for habitation in areas with extreme climates for millennia. The assumption about these same structures on Mars would be the same; for moderating extreme temperatures, as well as possibly offering protection from space radiation and even Martian dust. Based on underground residences on Earth, I do consider that possibilities exist for underground habitation or even balanced-environmental habitation on Mars. In this study, I focus attention on the terrestrial cyanobacterium “Nostoc sp. HK-01”. I discuss what we need to know and how the function of Nostoc sp. can be used in Mars habitation.

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Artificial fish production is one of the important food supply system in the world. On the other hand, aquaculture has been a pollutant source of natural water environment in no small part. This explanation introduces closed recirculating fish culture system which is expected to develop the aquaculture technology and improve economy further. The system has a lot of advantages including environmental conservation and food safety compared with other aquaculture systems. Furthermore closed ecological recirculating aquaculture system using artificial food chains is explained for the futural situation of aquaculture in space as the derivative technology with our accumulated knowledge on the management of the artificial food chain, rearing systems and postural control mechanism of aquatic animals under various gravity environments. Finally, the direction of future perspective for aquaculture function, technology and economics is discussed from the aspect of eco-engineering.

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The lecture introduces how to make a microcomputer-controlled, electronic device for a beginner. A series of lectures provides not only how to measure a physical property with an electronic sensor, convert it to a digit (analog digital conversion), switch on and off an electronic circuit with FET (Field Effect Transistor), and control those with a microcomputer but also practical know-how to design an actual electronic circuit, choose appropriate electronic parts, and mount those to a PCB (printed-circuit board), with explaining how to make “an acceleration switch”. The switch can automatically turn on and off a connected device according to an acceleration level measured with an acceleration sensor and contribute to parabolic flight experiments through size reduction of an apparatus, less operation, and precise control of the experiments.

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