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Subject of the test was a procedure of electron sterilization of Mars descent module units. As a result, data on distribution of absorbed dose field across the surface and by the entire volume of the mockup of a miniature meteorological station (MMS) were obtained In addition, electron sterilization technology was developed and the range of absorbed dose from electron radiation that will sterilize reliably packaged MMS hardware were defined in the interval from 30 to 40 kGy.

Purpose of the investigation was to develop a technique of irradiation sterilization of batch syringes with concentrated salt solutions (CaCl2 solution and a mixed solution of MgSO4, NaHCO3 and K2SO4). The syringes are used for mineralization of water produced by orbital systems of electrochemical regeneration of air humidity condensate, and deionized or distilled water from other sources. The paper describes composition of resultant potable water and analyzes quality of irradiation sterilization and stability of concentrated salts inside the syringes irradiated on gamma-source RTs-100M.

Two tasks must be accomplished to provide planetary protection for Mars return missions: (1) sterilization of the scientific module to be landed on Mars and (2) reliable sterilization of all material returned to Earth, while ensuring the scientific integrity of martian samples. This paper examines similarity and differences between these two tasks, and includes a discussion of technological implementation conditions and the nature of terrestrial and hypothesized martian microflora. The feasibility of a number of chemical and physical (ultraviolet and ionizing radiation and heating) methods of sterilization for use on the ground and onboard are discussed and compared. A combination of different methods will probably be selected as the most appropriate for ensuring planetary protection on the return mission.

The viewpoint of working group of Russian experts on the problem of planetary protection for future manned and unmanned Mars mission is presented. Recent data of Martian environment and on survival of terrestrial microorganisms in extreme conditions were used for detailed analysis and overview of planetary protection measures in regard to all possible flight situations including accidental landing. The special emphasis on "Mars-94" mission was done. This analysis resulted in revised formulation of spacecraft sterilization requirements and possible measures for their best implementation. New general combined approach to spacecraft sterilization was proposed. It includes penetrating radiation and heat treatment of spacecraft parts and components which is to be carried out before the final assembly of spacecraft and gaseous radiation sterilization of the whole spacecraft during the flight to Mars (or from Mars for return missions).

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.