The experimental study of microbial contamination of the space hardware.

The role of potential contaminants of design materials and products of space technology--aerobic and anaerobic prokaryotes (myxobacteria, eubacteria, corinebacteria, actinomyces), and eukaryotes (micromyces), psychrophilic, mesophilic and thermophilic forms, chemolythotrophic microorganisms is discussed in this paper. The methods of analysis of microbial contamination in the solution of problem of the planetary protection are considered. The necessity of the use of ultrasound at the evaluation of surface and subsurface contamination of specimens is demonstrated; methods of determination of buried contamination (with the use of organic solvents and mechanical pulverization) are discussed. The data on buried and subsurface contamination for some materials and electronic parts together with microflora resistivity to sterilizing treatment are given.

[The study of biocide effectiveness of ultraviolet treatment in media stimulating space station environment]. / Izuchenie biotsidnoi éffektivnosti ul'trafioletovoi obrabotki sred, modeliruiushchikh ob''ekty kosmicheskikh stantsii.

An experiment was performed to study the biocide effect of ultraviolet treatment of simulated space station milieu. UV generated by low and moderately power-intensive sources (from 10 W to 1 kW) showed a good promise for decontaminating, within the reach, solid structural materials, and the air and water in the cabin. For instance, within 10 minutes of the UV-treatment aerial bacteria in 20 m3 were reduced in 12 to 30 times while fungal microflora was fully suppressed. Water containing spores and vegetative cells of both pathogenic and nonpathogenic microorganisms became essentially sterile after 4 to 10 minutes of treatment with low UV (in the order of 0.01 W/cm2). Different UV modalities can lay the basis for development of specific technologies of microbial decontamination of various spacecraft.

[Model study of ozone microbial decontamination effectiveness of space station environment]. / Model'noe izuchenie éffektivnosti ozonirovaniia dlia mikrobnoi dekontaminatsii sred v kosmicheskikh stantsiiakh.

Modeling experiments were performed to evaluate bactericide and fungicide effects of small ozone concentrations (0.3 mg/l of water and 47 mg/m3 of air) that can be generated onboard spacecraft following one hour after treatment. Over the period of treatment, reduction in aquatic microorganisms made up, depending on biotest in use, hundred and more times; concentration of atmospheric microorganisms showed a 5- to 10-fold reduction. The demonstrated effectiveness of ozone shows that it may advantage sterilization and cleaning from microorganisms a number of life support systems aboard manned space vehicles and stations.

[Lethal and mutagenic action of nitrosomethylbiuret on a culture of the mycophilic fungus, Didymocladium ternatum]. / Letal'noe i mutagennoe deistvie nitrozometilbiureta na kul'turu mikofil'nogo griba Didymocladium ternatum

The effect of N-nitrozo-N-methylbiuret (NMB) on various features of Didymocladium ternatum, an organism producing termatin was studied. It was found that the lethal effect of NMB depended on the exposure time, prolongation of which resulted in increased numbers of the plus variants, morphological mutations and reverses into the populations. Variants possessing 8 times higher activity as compared to the initial culture were obtained as a result of selection of active variants.