Pulmonary challenges of prolonged journeys to space: taking your lungs to the moon.

Space flight presents a set of physiological challenges to the space explorer which result from the absence of gravity (or in the case of planetary exploration, partial gravity), radiation exposure, isolation and a prolonged period in a confined environment, distance from Earth, the need to venture outside in the hostile environment of the destination, and numerous other factors. Gravity affects regional lung function, and the human lung shows considerable alteration in function in low gravity; however, this alteration does not result in deleterious changes that compromise lung function upon return to Earth. The decompression stress associated with extravehicular activity, or spacewalk, does not appear to compromise lung function, and future habitat (living quarter) designs can be engineered to minimise this stress. Dust exposure is a significant health hazard in occupational settings such as mining, and exposure to extraterrestrial dust is an almost inevitable consequence of planetary exploration. The combination of altered pulmonary deposition of extraterrestrial dust and the potential for the dust to be highly toxic likely makes dust exposure the greatest threat to the lung in planetary exploration.