Solar radiation on Mars

Appelbaum, J.; Flood, Dennis J.

doi:10.1016/0038-092x(90)90156-7

Cited by 78 publications

(43 citation statements)

References 8 publications

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“…Based on these models, between 3.2 and 5.5 W m 2 of UVC irradiation is likely to reach the surface of equatorial Mars under clear-sky conditions (optical depths between 0.1 and 0.5). These UV fluence rates are generally estimated for the mean orbital distance of Mars but can increase or decrease, respectively, by approximately 18% for perihelion and aphelion positions in solar areocentric longitude (Appelbaum and Flood, 1990). These UV fluence rates have been shown to be capable of rapidly inactivating spores of UV resistant microorganisms during Mars simulations (Green et al, 1971;Hagen et al, 1964;Horneck et al, 2001;Mancinelli and Klovstad, 2000;Newcombe et al, 2005;Schuerger et al, 2003Schuerger et al, , 2005.…”

Section: Introductionmentioning

confidence: 97%

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

Schuerger

Richards

Newcombe

et al. 2006

Icarus

108

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Section: Introductionmentioning

confidence: 97%

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

Schuerger

Richards

Newcombe

et al. 2006

Icarus

108

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“…The MEC lighting system was calibrated to deliver 5.3, 7.6, 33.1, and 46 W m Ϫ2 of UVC, UVB, UVA, and total UV (200-400 nm), respectively to the upper surfaces of spacecraft materials. The UV-VIS-infrared fluence rates were created to simulate an optical depth (tau) of 0.1 on equatorial Mars at its mean orbital distance from the Sun (312 ϫ 10 6 km; 1.5236915 AU) and were based on previous models of martian surface irradiation (see Kuhn and Atreya, 1979;Appelbaum and Flood, 1990;Cockell et al, 2000;Patel et al, 2002;Schuerger et al, 2003). An optical depth of 0.1 tau on Mars was used to represent a worst-case scenario of UV irradiation that might be encountered under extremely clear-sky conditions.…”

Section: Mars Simulation Chambermentioning

confidence: 99%

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

et al. 2005

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Layers of dormant endospores of Bacillus subtilis HA101 were applied to eight different spacecraft materials and exposed to martian conditions of low pressure (8.5 mbar), low temperature (؊10°C), and high CO 2 gas composition and irradiated with a Mars-normal ultraviolet (UV-visible-near-infrared spectrum. Bacterial layers were exposed to either 1 min or 1 h of Mars-normal UV irradiation, which simulated clear-sky conditions on equatorial Mars (0.1 tau). When exposed to 1 min of Mars UV irradiation, the numbers of viable endospores of B. subtilis were reduced three to four orders of magnitude for two brands of aluminum (Al), stainless steel, chemfilm-treated Al, clear-anodized Al, and black-anodized Al coupons. In contrast, bacterial survival was reduced only one to two orders of magnitude for endospores on the non-metal materials astroquartz and graphite composite when bacterial endospores were exposed to 1 min of Mars UV irradiation. When bacterial monolayers were exposed to 1 h of Mars UV irradiation, no viable bacteria were recovered from the six metal coupons listed above. In contrast, bacterial survival was reduced only two to three orders of magnitude for spore layers on astroquartz and graphite composite exposed to 1 h of Mars UV irradiation. Scanning electron microscopy images of the bacterial monolayers on all eight spacecraft materials revealed that endospores of B. subtilis formed large aggregates of multilayered spores on astroquartz and graphite composite, but not on the other six spacecraft materials. It is likely that the formation of multilayered aggregates of endospores on astroquartz and graphite composite is responsible for the enhanced survival of bacterial cells on these materials.

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“…This leads to a peak OD of about 6, compared to 3.5 in [8], for the second dust storm at the Viking 1 landing site.…”

Section: Power Requirementsmentioning

confidence: 96%

“…Mars equatorial regions and have only a minor impact on NASAJTM--1999-209288 I seasonal insolation due to their limited size, duration (a few days) and moderate OD (-1) [8]. Sunlight is also obscured by dust hazes, ground fogs (specific to site and local weather), CO2 and water ice clouds [9].…”

Section: Mars Environmentsmentioning

confidence: 99%

“…Power requirements for an example 1130-day mission (with a single ISRU lander and a single crew surface habitat) are divided into two parts: (1) base loads, given in Table 1, and (2) Storm seasonal, temporal and spatial (versus landing site latitude) characteristics are described in [8]. Dust storm peak OD was taken as the average of the lower limit of measured OD and the estimated maximum OD value for storms encountered by the Viking Landers [40].…”

Section: Power Requirementsmentioning

confidence: 99%

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