Springer Online Journal Archives 1860-2000
Abstract Studies were conducted to determine the effects of a simulated Martian environment on the survival of terrestrial microorganisms. Mariner IV data were utilized to establish the Martian model. Day/night cycling, temperature, humidity, pressure, atmospheric constituents and solar irradiation were controlled in a 3600 ft3 simulation chamber at the Boeing Kent Space Simulation Laboratory. Microorganisms used in this study included suspensions of:Bacillus subtilis var.niger spores, a psychrophilic sporeformer, and the organisms contained in a soil emulsion prepared from several soils. Aliquots of each suspension were placed on separate sterile stainless steel planchets, air dried, and positioned in 4 layers in sterile limonite. One-half of the samples placed on the surface received the total solar spectrum (0.44 earth solar constants); the remainder of the surface samples received the above treatment minus the ultraviolet (UV) portion of the spectrum. Subsurface samples were placed in limonite at depths of 0.5, 1.5 and 3 in. Survival data were obtained for chamber exposure periods of 2, 4, and 8 days. These data indicate that: (1) organisms exposed to the total solar spectrum did not survive, (2) a time dependent, 1 to 3 log, reduction in numbers occurred in the surface samples that received the solar spectrum minus UV, and (3) subsurface survival varied with depth and type or organism.
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