title: The Martian and extraterrestrial UV radiation environment--1. Biological and closed-loop ecosystem considerations.
abstract: The Martian surface is exposed to both UVC radiation (<280 nm) and higher doses of UVB (280-315 nm) compared to the surface of the Earth. Terrestrial organisms have not evolved to cope with such high levels of UVC and UVB and thus any attempts to introduce organisms to Mars, particularly in closed-loop life support systems that use ambient sunlight, must address this problem. Here we examine the UV radiation environment of Mars with respect to biological systems. Action spectra and UV surface fluxes are used to estimate the UV stress that both DNA and chloroplasts would experience. From this vantage point it is possible to consider appropriate measures to address the problem of the Martian UV environment for future long term human exploration and settlement strategies. Some prospects for improving the UV tolerance of organisms are also discussed. Existing artificial ecosystems such as Biosphere 2 can provide some insights into design strategies pertinent to high UV environments. Some prospects for improving the UV tolerance of organisms are also discussed. The data also have implications for the establishment of closed-loop ecosystems using natural sunlight on the lunar surface and elsewhere in the Solar System.
authors.affiliation: Department of Plant Biology, Carnegie Institute of Washington, Stanford, CA 94035-1297, USA. cockell@biosphere.stanford.edu
authors.forename: C S
authors.initials: CS
authors.lastname: Cockell
authors.forename: A L
authors.initials: AL
authors.lastname: Andrady
mesh_terms: D000818:Animals; D004249:DNA Damage; D018504:Ecological Systems, Closed; D004783:Environmental Microbiology; D005118:Extraterrestrial Environment; D006801:Humans; D018535:Mars; D010944:Plants / Q000528:radiation effects*; D011835:Radiation Protection; D011836:Radiation Tolerance; D013026:Space Flight; D018561:Space Simulation; D014466:Ultraviolet Rays