Lichen Vitality After a Space Flight on Board the EXPOSE-R2 Facility Outside the International Space Station: Results of the Biology and Mars Experiment

作者：Rosa de la Torre Noetzel, María Victoria Ortega‐García, Ana Z. Miller, Olga Bassy, Carmen Granja, Beatriz Cubero, Luísa Jordão, Jesús Martínez‐Frías, Elke Rabbow, Theresa Backhaus, S. Ott, Leopoldo G. Sancho, Jean‐Pierre de Vera · 发表于：Astrobiology · 年份：2020 · DOI：10.1089/ast.2018.1959 · 被引用次数：25 · 研究领域：Lichen and fungal ecology、Biocrusts and Microbial Ecology、Planetary Science and Exploration

were placed on the exposure platform EXPOSE-R2, on the International Space Station (ISS) and exposed to space and to a Mars-simulated environment for 18 months (2014-2016) to study: (1) resistance to space and Mars-like conditions and (2) biomarkers for use in future space missions (Exo-Mars). When the experiment returned (June 2016), initial analysis showed rapid recovery of photosystem II activity in the samples exposed exclusively to space vacuum and a Mars-like atmosphere. Significantly reduced recovery levels were observed in Sun-exposed samples, and electron and fluorescence microscopy (transmission electron microscope and field emission scanning electron microscope) data indicated that this was attributable to the combined effects of space radiation and space vacuum, as unirradiated samples exhibited less marked morphological changes compared with Sun-exposed samples. Polymerase chain reaction analyses confirmed that there was DNA damage in lichen exposed to harsh space and Mars-like environmental conditions, with ultraviolet radiation combined with space vacuum causing the most damage. These findings contribute to the characterization of space- and Mars-resistant organisms that are relevant to Mars habitability.