THE NUCLEUS Issue 2 Spring 2024

HOW SPACE TRAVEL AFFECTS THE BODY by Lexi Humber

The short-term nausea that astronauts face upon returning to earth can last up to 10 days after landing, with symptoms including vertigo, cold sweating, vomiting and more. The reason this occurs is due to the astronaut needing to get reacclimatised with earth's gravity after being in a microgravity environment for an extended period. Furthermore, while in space, the lack of gravity affects the inner ear causing astronauts to feel a loss of balance, co-ordination and spatial tracking so it ’ s difficult for them to pilot and complete tasks, making their work even more impressive. NASA preformed an in-depth study on a pair of twins, Scott and Mark Kelly. One twin travelled to the international space station for a year whilst his brother remained on earth and this caused differences in their genes. Scott's genes were observed to have an increase in methylation, which is the process of ‘ turning genes on and off ’ . There are dangers associated with this, as it changes the genes which can lead to diseases. Methylation is one of the basics of epigenetics, that shows how a change in environment can alter our genes. Furthermore, space travel has also been proven to alter the telomeres within the genes. Telomeres are structures attached to the end of the genes that are responsible for protecting the strands from being destroyed. Research has found that they elongate in length and shrink once returning to earth, which may be attributed to chronic oxidative stress. This research is key in discovering ways that humans may, in the future, be able to travel safely into space for long periods of time, aiding the progress of science. Overall, space travel affects the body in many ways that are detrimental to astronauts ’ mental and physical health, and this makes their work that much more impressive.

Astronauts face extreme isolation, radiation, microgravity and more on a daily basis. Space travel can cause their bones to degrade, (calcium being shown in the urine). But surely once they come back to earth all their problems are over? Wrong. Upon returning to earth, astronauts must face some of the long lasting or even permanent effects on their body, some of them being blindness, muscle and bone loss, and increased risk of cancer and even changes to the genome. Astronaut Michael Barratt ’ s journey to the international space station in 2009 made him experience some eyesight loss. This sparked research in the correlation between vision loss and space travel. The reason that many astronauts in the past experienced eyesight loss is due to an increase in pressure on the skull and brain due to microgravity. Fluids shift within the brain causing the optic nerve to swell and this causes the eye to change structure. NASA have now identified these symptoms as a part of (SANS) Space associated neuro-ocular syndrome and the symptoms can be permanent for the individual. Gravity on earth usually distributes blood evenly around the body, however in space the lack of gravity can cause blood to ‘ accumulate in the brain ’ which can lead to diseases such as oedema, an accumulation of fluid in the body.

-08-