Survival of bacterial and fungal spores in the expose-r2 experiment

The primary goal of the Biodiversity experiment, which was part of the Expose-R2 study, was to assess the effects of a prolonged exposure to the space environment on the survival of dormant microorganisms. To do this, units containing samples of bacterial and fungal spores were mounted on a support platform attached to the exterior wall of the Russian Zvezda Module of the International Space Station (ISS). After a 15-mon exposure to outer space the samples were returned to Earth. The experiment demonstrated that microbial spores had the capability to survive and remain viable after the exposure to outer space for the time period comparable to the Earth-Mars-Earth mission duration. This finding is not only of theoretical importance but also of practical significance as related to the development of adequate measures of planetary protection for deep space missions.