We don’t want to conquer the cosmos,
we simply want to extend the boundaries of Earth to the frontiers of the cosmos
Stanisław Lem, Solaris
Despite seeming easiness and romantic attraction, long term space flights cause several threats to astronauts’ health and wellbeing as people are subject to many stressful conditions (radiation, microgravity, g-forces, anxiety, psychological stress, changes in health status, loss of body mass, etc.).
Human bodies undergo dramatic changes with the absence of gravity as weightlessness significantly complicates daily life and results in the weakening of bones and muscles, poor coordination. Due to the lack of gravity, back vertebrae separate slightly contributing to the change in the height of astronauts and backaches. In space they grow up to two inches taller. Regular exercises in space and upon return help the crew to slow the loss and counter side effects. Thus some scientists believe that artificial gravity is necessary for the crew during the future Mars mission [3, 4]. Low gravity also impacts blood circulation. On Earth, blood is naturally drawn downward by the force of gravity; whereas, in space bodily fluids no longer flow back down. Sometimes it causes headaches, nasal congestion, red and swollen eyes and space sickness.
Astronauts have to struggle with high radiation levels emitted by the Sun, distant stars and galaxies. There are occasional solar flares that provoke enormous life-threatening radiation from the Sun. Space radiation gives rise to cancer, changes in motor functions, neurological disorders and serious diseases . Exposure to radiation and high-energy particles account for cognitive problems.
Atmospheric contaminants, higher intracranial pressure, noise level at the spacecraft cause temporary hearing loss. Microgravity and rise of fluid that occurs in a person’s body in a weightless lead to another health hazard — blurred vision.
In addition, there are some factors that cause stress, fatigue, insomnia, sickness, bad interpersonal relations and mistakes among astronauts:
- unusual environment;
- irregular light patterns (the sun rises and sets every 90 minutes when the spacecraft orbits Earth);
- constant noise;
- cooling systems in space suits;
- absence of shower;
- high level of carbon dioxide;
- demanding schedule;
- 24 hours camera .
All this makes quality sleep rather challenging and most astronauts rely on sleep medication to get some rest. Astronauts sleep in individual sleeping bags. Poor sleep leads to interpersonal conflicts, depression, tension and anxiety. Scientists and engineers are working on replacing orbit bulbs to create more comfortable lighting and day-night cycles on spacecraft.
Additionally, astronauts have to overcome certain challenges concerning human psychology such as food intake. Food and meals play a great psychosocial role in remote, stressful, exhausting environments. Long flights reveal many nutritional problems. Astronauts need a balanced diet to support the quality of their life and their nutrition needs are generated from ground-based studies. Before departure, they select desired food items from available choices assembled by nutritionists. Crew members are provided with carefully selected individual portions, adequate diets to ensure health, convenience and minimize immune alterations, changes in muscle, bone and fluid loss on long flights [2, 6, 7].
Life in space also means living with a distinct lack of space. When astronauts return to Earth, they need time to readjust to gravity, as its sudden reintroduction causes low blood pressure and lightheadedness. On the whole, there are many dangers of long-distance space flights, but with advanced engineering developments and proper safety precautions we are moving forward to longer deep space missions.
1. About space radiation. http://spaceradiation.usra.edu/about/ (accessed April 12, 2015).
2. Cena H., Sculati M., Roggi C. Nutritional concerns and possible countermeasures to nutritional issues related to space flight // Eur J Nutr. 2003, No. 42(2). P. 99–110.
3. Known effects of long-term space flights on the human body http://www.racetomars.ca/mars/article_effects.jsp (accessed April 12, 2015).
4. Life in space http://www.racetomars.ca/mars/article_life_space.jsp (accessed April 12, 2015).
5. Palinkas L. A. Psychosocial issues in long-term space flight: overview // Gravitational and space biology bulletin. 2001, No. 14(2). P. 25–33.
6. Smith S. M., Davis-Street J., Rice B. L. and Lane H. W. Nutrition in Space // Nutrition Today, Vol. 32, No. 1, P. 6–12.
7. Space and food nutrition — an educator’s guide with activities in science and mathematics. http://www.nasa.gov/pdf/143163main_Space.Food.and.Nutrition.pdf (accessed April 12, 2015).
8. Weightlessness and weight loss: malnutrition in space. https://escholarship.org/uc/item/91v8027g#page-1 (accessed April 12, 2015).