Micro-organisms under a Simulated Martian Environment

Rapid inactivation of seven Bacillus spp. under simulated Mars UV irradiation☆

“…are more resistant than non-spore forming species to the harsh environmental conditions in space (reviewed by Horneck, 1992;Nicholson et al, 2000Nicholson et al, , 2005Schuerger, 2004), and Bacillus spp. are commonly used in studies exploring the effects of the martian environment on microbial survival (Green et al, 1971;Hagen et al, 1964;Hawrylewicz et al, 1964;Koike et al, 1996;Mancinelli and Klovstad, 2000;Schuerger et al, 2003Schuerger et al, , 2005. A preliminary report of these experiments has been published .…”

Surface Characteristics of Spacecraft Components Affect the Aggregation of Microorganisms and May Lead to Different Survival Rates of Bacteria on Mars Landers

“…The key biocidal factors for terrestrial microorganisms on Mars are: (i) low atmospheric pressure, (ii) high solar ultraviolet (UV) irradiation, (iii) severe desiccating conditions, (iv) extreme temperature fluctuations, (v) solar particle events, and (vi) galactic cosmic rays (reviewed by Schuerger, 2004). Despite these extreme conditions many studies have demonstrated that terrestrial microorganisms can survive simulated martian conditions as long as they are protected from solar UV irradiation (Packer et al, 1963;Hagen et al, 1964Hagen et al, , 1967Hawrylewicz et al, 1964;Green et al, 1971;Foster et al, 1978;Koike et al, 1996;Mancinelli and Klovstad, 2000;Schuerger et al, 2003;reviewed by Schuerger, 2004).…”

“…Although these studies examined different questions concerning microbial survival under simulated martian conditions, a few general conclusions may be drawn from this body of work. First, dormant spores of terrestrial microorganisms survived well under low temperature, low pressure, and N 2 or CO 2 atmospheres, though reductions in microbial populations of one to several orders of magnitude occurred (Packer et al, 1963;Hagen et al, 1964;Hawrylewicz et al, 1964;Green et al, 1971;Imshenetsky et al, 1973;Foster et al, 1978). Second, UV irradiation was the key parameter that determined survivability of microorganisms under simulated martian conditions; direct exposure to UV irradiation resulted in rapid and nearly complete inactivation of microbial cultures (Packer et al, 1963;Green et al, 1971;Koike et al, 1996;Mancinelli and Klovstad, 2000;Schuerger et al, 2003).…”

“…Most of the early literature on microbial survival under martian conditions mixed viable cells of test organisms into terrestrial or Mars analog soils (Packer et al, 1963;Hagen et al, 1964Hagen et al, , 1967Hawrylewicz et al, 1964;Scher et al, 1964;Foster et al, 1978). In addition, microbial species during martian simulations have been placed on agar surfaces (Imshenetsky et al, 1973), in crushed sandstone (Fulton, 1960;Roberts and Wayne, 1962), in limonite , on glass (Imshenetsky et al, 1967) or stainless steel planchets, and on aluminum coupons (Hagen et al, 1971;Koike et al, 1996;Mancinelli and Klovstad, 2000;Schuerger et al, 2003;Schuerger and Kern, 2004).…”

“…B. subtilis was chosen for this study because it is a common contaminant of spacecraft surfaces (Puleo et al, 1973(Puleo et al, , 1977Venkateswaran et al, 2001;La Duc et al, 2003, 2004, and it has been used in previous studies under martian conditions Hawrylewicz et al, 1964;Green et al, 1971;Koike et al, 1996;Mancinelli and Klovstad, 2000;Schuerger et al, 2003).…”