POST-MISSION SEQUELAE OF LONG-DURATION SPACE FLIGHT

• Main Authors: Warmflash, D, Barr, Y R, Leblanc, A D, Jennings, R T, Garcia, Y, Jones, J A
• Format: Conference Proceeding
• Language: English
• ISSN: 0095-6562

Exploration class missions will expose astronauts to prolonged periods of weightlessness, radiation, lunar dust, and a variety of physiological perturbations. In addition to affecting crew health and performance during the mission, these exposures may impact the long-term health of astronauts subsequent to returning to Earth. Possible perceived consequences of long duration exploration missions include: 1) Muscle deconditioning and bone loss resulting from weightlessness. Either of these may require rehabilitation; the latter may result in permanent architectural changes and increased fracture risk. 2) Nephrolithiasis, resulting from weightlessness and increased urinary calcium excretion, may warrant medical and/or surgical intervention after completion of the mission. 3) Inhalation of lunar dust during lunar missions may predispose the exposed crew to a pneumoconiosis and potentially an increased risk of pulmonary malignancies. 4) Cataracts. 5) Fibrotic diseases. 6) Malignancy. 7) Transient or permanent reduction in fertility. The incidence of the latter four may increase because of exposure to space radiation. While it has yet to be determined whether the linear no threshold model is applicable to modest exposure levels ( < 2 cG/day) and for all cancers, other factors (altered genetic repair mechanisms, immune system dysfunction resulting from weightlessness and psychosocial stress, and disruption of circadian release of melatonin) may affect cancer initiation and progression risk. None of these risks should be seen as an obstacle to human exploration of interplanetary space. Nevertheless, the use of primary prevention strategies in the form of countermeasures to reduce mission and post-mission risk should be integral to medical planning of the mission. Long-term monitoring of returning astronauts for early detection of conditions for which they are at particular risk is also justified for the purpose of providing a secondary prevention safety net.