Microbiology of the Built Environment in Spacecraft Used for Human Flight

Abstract Spacecraft, associated with human spaceflight, is one of the more unusual microbial environments. In contrast to other terrestrial environments, microorganisms within spacecraft are completely isolated from the rest of the biosphere and experience greatly reduced gravity (microgravity) and increased exposure to solar radiation. Microorganisms are introduced to this environment primarily through the microbiomes associated with spacecrew, as well as small numbers of microorganisms inadvertently introduced with supplies and equipment. In short-term studies (