In space, continuous exposure to microgravity and increased doses of ionizing radiation, create an environment which is unfamiliar for the Earth-bound human body. Furthermore, due to isolation, confinement, and high workload, the levels of psychological stress in space are elevated. This unique combination of spaceflight stressors can affect the astronaut’s health both at the short and long term.
The skin is the largest organ of the human body and it holds some vital functions for human health. However, during spaceflight, skin problems such as itch, dryness, rashes, and small cutaneous wounds are the most reported health problems. Furthermore, after long-term spaceflight, a 20% reduction in thickness of the epidermis and a loss of elasticity has been observed (Tronnier, Wiebusch, & Heinrich, 2008). Of additional concern during spaceflight is the central nervous system. In fact, neurological symptoms such as space motion sickness, nausea and headaches are commonly experienced in astronauts during the first days in microgravity (Clément, 2011). , while persistent brain-volume changes and decrease gray matter (GM) volume are observed after long duration spaceflight (Van Ombergen et al., 2018). On top, long-term exposure to the space environment is reported to induce visual impairments, cognitive deficits, and premature brain aging (Clément, 2011; Cucinotta, Wang, & Huff, 2016; Zhang & Hargens, 2018).
On Earth, simulation studies mostly investigate the effect of single spaceflight stressors, which fail to grasp the complete picture of the hazardous space environment. Therefore, a more thorough investigation of the combined effect of microgravity, ionizing radiation, and psychological stress on the skin and the brain is warranted.
Clément, G. (2011). Fundamentals of Space Medicine (Second). New York: Springer Science+Business Media.
Cucinotta, F. A., Wang, H., & Huff, J. L. (2016). Risk of Acute or Late Central Nervous System Effects from Radiation Exposure, (May).
Tronnier, H., Wiebusch, M., & Heinrich, U. (2008). Change in skin physiological parameters in space - Report on and results of the first study on man. Skin Pharmacology and Physiology, 21(5), 283–292. https://doi.org/10.1159/000148045
Van Ombergen, A., Jillings, S., Jeurissen, B., Tomilovskaya, E., Rühl, M., Rumshiskaya, A., … Wuyts, F. L. (2018). Brain Tissue – Volume Changes in Cosmonauts. The New England Journal of Medicine, 379(17), 2018–2020.
Zhang, L.-F., & Hargens, A. R. (2018). Spaceflight-Induced Intracranial Hypertension and Visual Impairment: Pathophysiology and Countermeasures. Physiological Reviews, 98(1), 59–87. https://doi.org/10.1152/physrev.00017.2016