PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 11537132

Lunar base extension program and closed loop life support systems.

K Nitta·H Ohya
View original source ↗Export metadata ↓

Abstract

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 3He 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. 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.

Explore related subjects

Carbon DioxideEcological Systems, ClosedFeasibility StudiesFood SupplyHumansLife Support SystemsMetabolismMoonNitrogen FixationOxygenPhotosynthesisPlant DevelopmentPlantsWaste ManagementWater PurificationJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

K Nitta, H Ohya. 1991. Lunar base extension program and closed loop life support systems.. https://doi.org/10.1016/0094-5765(91)90125-o

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2002

Selective separation of cis-trans geometrical isomers of beta-carotene via CO2 supercritical fluid extraction.

We investigated a novel method for the selective separation of beta-carotene isomers from a freeze-dried powder of the algae Dunaliella bardawil using supercritical fluid extraction. The separation method relies on the different dissolution rate of the 9Z and all-E isomers of beta-carotene in SC-CO(2). At first, the equilibrium solubility of the two isomers in SC-CO(2) was determined at the extraction conditions of 44.8 MPa and 40 degrees C. The solubility of the 9Z isomer was found to be nearly 4 times higher than that of the all-E isomer (1.92 x 10(-5) g all-E isomer/g CO(2) compared to 7.64 x 10(-5) g 9Z isomer/g CO(2)). When supercritical fluid extraction was applied to a carotenoid concentrate from the algae (29 wt% beta-carotene) or a freeze-dried powder of the algae (3.1% beta-carotene), a selective separation of the 9Z/all-E isomers of beta-carotene was obtained. Thirty-nine percent recovery of beta-carotene with 80% purity of 9Z isomer was achieved at the initial stages of extraction (40 mL CO(2)). The extraction rate of beta-carotene from the freeze-dried algae powder was slower than that from the carotenoid concentrate, resulting in a reduction in the recovery and purity of the 9Z isomer. This indicates that even at the initial stage of the extraction the internal mass resistance is significant. Isomer purity and recovery could be enhanced upon grinding of the algae powder.

Carbon Dioxide↗
PubMed2002

Supercritical CO(2) fluid extraction of crystal water from trehalose dihydrate. Efficient production of form II (T(alpha)) phase.

Form II is a kind of metastable crystalline form of trehalose anhydrate, and it is easily converted to the dihydrate crystal by absorbing water in moist atmosphere at room temperature (Akao et al., Carbohydr. Res. 2001, 334, 233-241). It can be utilized as an edible and nontoxic desiccant, and thus its efficient production from the dihydrate is significant from a viewpoint of industrial applications. In this study, we attempt to extract crystal water from the dihydrate using supercritical CO(2). We examine the dependence of extraction efficiency on the extraction time, the temperature and pressure of the fluid. Then, FTIR measurements are carried out to detect the extracted water and to identify the polymorphic phase of the sugar sample after the extraction treatment. In particular, the so-called first derivative euclidean distance analysis for IR spectra is shown to be quite useful for the structural identification. Consequently, we demonstrate that form II is produced from the dihydrate through supercritical CO(2) fluid extraction if appropriate temperature and pressure conditions (around 80 degrees C and 20 MPa) are maintained.

Carbon Dioxide↗
PubMed2002

Comparative physicochemical properties of hydrocortisone-PVP composites prepared using supercritical carbon dioxide by the GAS anti-solvent recrystallization process, by coprecipitation and by spray drying.

Hydrocortisone-PVP composites were successfully prepared using the supercritical fluid gas anti-solvent method (GAS). Analysis by differential scanning calorimetry DSC and powder X-ray diffraction (XRD) indicated that these systems were more crystalline than corresponding systems prepared by spray drying. These systems, prepared by the GAS method were more similar in physicochemical properties to coprecipitates prepared by conventional solvent evaporation. Compressed composites of hydrocortisone-PVP systems, prepared by the GAS method, had dissolution rates lower than those of corresponding systems prepared by the other processing methods but equivalent to those of corresponding physical mixtures.

Carbon Dioxide↗