Introducing our new special guest editor, Philip Vukovic – BSc (Melb). Many thanks to Philip for this wonderful introductory piece for anyone who is curious about the effects of spaceflight on humans.
As we continue to embark on our journey through the austere and challenging environments of space, further research in space medicine and life sciences will become even more important for mission success.
Understanding some of the medical and physiological problems associated with spaceflight will provide the backbone through which we can continue to develop effective means to support the survival, health and performance of astronauts and commercial crew members.
What are the “space life sciences”?
As defined by NASA, the space life sciences study interactions between living organisms and characteristics of the space environment. These studies specifically address the structure and function of living organisms in space and interdependent relationships of organisms with each other and/or the space environment while also touching on the origin, evolution and potential for extraterrestrial life.
Spaceflight results in many medical and physiological effects on the human body. Many such effects on the human body result due to microgravity, which refers to the near weightlessness environment encountered in space.
As stated by Kunihiko Tanaka et al. (2017), exposure to microgravity can result in changes in the musculoskeletal, cardiovascular, and vestibular systems. Astronauts who are exposed to such environments immediately begin to experience bone loss, which raises concerns about fracture risk and increased long-term risk of osteoporosis. The vestibular system, which helps to maintain balance and provide information about body position, is impacted by microgravity. Once astronauts return to Earth, they are often supported when emerging from the capsule as they may experience problems standing and walking due to microgravity’s effects on the vestibular system.
Radiation is one of the most menacing and pressing concerns associated with long-duration spaceflight. The risks associated with radiation in spaceflight pose many problems and influence the planning, execution and operational decisions of missions.
Jeffery C. Chancellor et al. (2014) state that exposure to space radiation exacerbates the risk of cancer and increases the likelihood of experiencing central nervous system problems. Space radiation can also narrow arteries and damage the heart, ultimately resulting in cardiovascular disease. On a cellular level, the primary means through which radiation poses a problem, is by damaging DNA. Such effects on DNA may cause several changes to genes, which can potentially lead to cancer.
Isolation and Confinement
Confinement to a small space, with a small group of individuals, over long periods of time will inevitably result in problems. With missions to Mars being in discussion, crews will need to be carefully chosen, trained and supported in order to safely succeed in the 480-million-kilometre journey to Mars and back.
Pagel and Choukèr (2016) highlighted the numerous harmful effects that the human body experiences when subjected to long-periods of isolation and confinement. Various long duration isolation and confinement analogue studies have shown that individuals may experience symptoms of depression, a reduction in positive emotion ratings and cognitive impairment. Quality of sleep can also be significantly affected, posing serious problems to the health of astronauts and to the timely and successful completion of daily space tasks.
The frontiers of space medicine
Whilst a plethora of research and literature exists regarding space medicine, further research is necessary to ensure safe manned space explorations. Travelling the cosmos and conducting interplanetary missions will be a bold endeavour, but as former US President John F Kennedy famously proclaimed, “We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.”
NASA (2013, December 19). About Space Life Sciences Website. Retrieved from https://www.nasa.gov/audience/foreducators/spacelife/about/index.html#.YaBJptBBxPZ.
NASA (2019, May 9). 5 Hazards of Human Spaceflight. Retrieved from https://www.nasa.gov/hrp/5-hazards-of-human-spaceflight.
Tanaka, K., Nishimura, N., & Kawai, Y. (2017). Adaptation to microgravity, deconditioning, and countermeasures. The Journal of Physiological Sciences, 67(2), 271-281. https://jps.biomedcentral.com/articles/10.1007/s12576-016-0514-8
Chancellor, J. C., Scott, G. B., & Sutton, J. P. (2014). Space radiation: the number one risk to astronaut health beyond low earth orbit. Life, 4(3), 491-510. https://journals.physiology.org/doi/full/10.1152/japplphysiol.00928.2015
Pagel, J. I., Choukèr, A. (2016). Effects of isolation and confinement on humans-implications for manned space explorations. Journal of Applied Physiology. https://journals.physiology.org/doi/full/10.1152/japplphysiol.00928.2015