In the Closed Ecological Life Support System (CELSS) concepts which have been proposed up to now, most of the foods to be provided to the crew have been based on plant and vegetable produce.
In this paper, a snail breeding module which will serve, as a subsystem of CELSS, to provide the space crew with animal nutrients has been studied. As a source of nutrition for the crew, snails have various advantages over other animal species.
Snails can normally be bred in a limited space and they are insensitive to the lack of oxygen and feed. In this breeding module, a species of snail (Helix pomatia) will grow, mature, mate and reproduce.
In order to minimize the crew's work, automated operations for feeding, cleaning wastes, handling snails and their spawn, as well as for the maintenance of the module, will be applied. A submodule which processes snails for food production is also studied. In addition to automation, other features taken into account are economy from the view point of utilities counsumed, and the desirsbility of a lighweight, compact module.
Further, to prevent possible biocontamination, which may originate from lifeforms inside the module, diffusing to pressurized quarters of the space vehicles, a high level of inter-module sealing will be achieved.
As a biological study of snails in space, five snailes snd spawn were launched on May 18th (1991) by the Soviet soyuz rocket and were in the space orbital MIR for a week. They returned to the earth on May 26th (1991). The snails snd spawn are now being in our laboratory.

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The plant cultural sub-system which is a part of CELSS, such as a lunar base or space station, plays an important role in supplying foods and O₂ for residents and in absorbing the CO₂ exhausted.
Optical radiation is an essential environmental element for plant growth. An artificial lighting system in this sub-system will be used as the optical radiation supplying system. One of the reason is the length of the day in space is quite different from that on earth, so sunlight is not suitable for plant growth. Also, it is very essential that vegetables be supplied reliably and on schedule.
In this report, artificial radiant sources now used conventionally were estimated from the viewpoint of plant growth. From the results, it was found that a 3-band fluorescent lamp can be used as a radiant source of the sub-system. This paper also discusses trial lamps, including far-red radiation, which are usually deficient in fluorescent lamps.

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A well-controlled gas exchanging system provides a reliable and comfortable condition to crews in a perfectly closed atmosphere such as spacecraft. Carbon dioxide (CO₂) generated with human metabolism must be controlled within a low level concentration because of physiological reasons. Some chemical substances are well known to remove rare CO₂ gas in a cabin atmosphere. Lithium hydroxide and zeolite molecular sieves have been utilized to prevent an atmosphere CO₂ concentration from increasing in spacecraft, submarine, and so forth. A new CO₂ removal agent called Solid Amine repeatedly works well in adsorbing CO₂ gas component independent of moisture in a cabin atmosphere. In general, solid amine is composed of porous material with amine groups on it and has a large amount of surface area. This type of adsorbent, however, has not yet utilized in closed gas control system. This paper deals with some basic characteristics of solid amine concerning adsorption capability (adsorption isotherm), characteristics of dynamic adsorptions (breakthrough phenomena in a fixed bed), and diffusion mechanism of CO₂ molecule into adsorbent surface pores.

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A new type of carbon dioxide (CO₂) removal substance so called solid amine has good features to keep a closed cabin atmosphere clean in manned spacecraft. It can adsorb rare CO₂ gas repeatedly by use of regeneration process with small amounts of thermal energy and/ or depressurizing. It is also available to adsorb water composition simultaneously. An ordinary CO₂ removal agent, lithium hydroxide (LiOH), has larger amounts of CO₂ removal capacity than that of solid amine; however, decomposition process to purge reacted CO₂ requires high temperature and large amounts of energy, so that loading weight will become larger in proportion as duration time and crew number. Another well-known CO₂ removal agent, zeolite molecular sieves, needs a desiccant process to efficiently adsorb CO₂ gas. Solid amine has unique characteristics in comparison with lithium hydroxide and zeolite. Basic characteristics of solid amine are described in another paper (12) concerning adsorption equilibrium, breakthrough data in a fixed bed system, and diffusion mechanism under N₂ gas atmosphere condition. This paper deals with moisture adsorption on solid amine, effects of humidity to CO₂ removal capacity, and mechanism of bicomponent adsorption of CO₂ and moisture in air at room temperature.

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Chlorophyous, cultured cells of Marchantia polymorpha (HYA- 2F cell line) grew actively under photoautotrophic conditions. The specific growth rate (μ_{_??_}) and the doubling time were 0.69days^-1 and 1.0 days respectively under the condition of 7000 lux luminous intensity, and 1% carbon dioxide enriched atmosphere at 25°C, Carbon dioxide absorption was estimated and it was revealed that the absorption rate was the highest at linear phase. The maximum carbon dioxide fixation rate was 238 mg·C/day·l in linear phase when population density was high enough that the incident light was almost completely absorbed by the cell suspension.

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To analyze systematically large-scale mass circulation networks in CELSS (Closed Ecological Life Support Systems), a powerful method called Biochemical Systems Theory (BST) is intruduced. As an example, BST is used to analyze a simple closed system with oxygen circulation and is shown to work right and to be very useful. Finally, it is emphasized that analysis of the CELSS networks is indispensable to making a success in its long-term operation.

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To characterize CELSS (Closed Ecological Life Support Systems) networks, two kinds of simple closed system models that have two- and four-dependent variables, respectively, are investigated. The CELSS matrix, which is directly yielded within the framework of BST (Biochemical Systems Theory) in a steady state, is singular and does not provide steady-state values for the dependent variables. Nevertheless, in dynamic calculation the dependent variables converge on their respective constant values, which is a contradictory behavior to common sence. This is because of the existence of an alternative equation derived from the law of conservation of mass, which equation is characteristic of CELSS and is automatically satisfied in calculation. On the basis of this finding, BST is modified so as to adapt to the analysis of large-scale mass circulation in CELSS.

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