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Name: Niki R.
ProgramYear: 2008 Submit Date: May 21, 2008 Review Date: Jun 3, 2008 Every living being on Earth is accustomed to the presence of gravity; when the presence of gravity is altered or removed, biological processes can go awry. This consequence of space exploration has caused an immense obstacle for astronauts and life science researchers. While humans, with the necessary equipment, oxygen, and food, have little difficulty surviving in space for short periods of time, long-term exposure to microgravity can trigger harmful physiological responses in the human body. A number of such effects range from serious medical conditions to less severe side effects, including bone loss, de-conditioning, muscle atrophy, alterations in the immune system, as well as some cardiovascular issues. Although scientists remain unaware of the most effective and efficient way to overcome this obstacle, some forms of precaution do exist, and scientists continue to experiment and research in a quest to prevent negative physiological effects of microgravity so that someday, humans can endure long-duration space exploration. Various minor affects of weightlessness remain consequences of weightlessness. One significant affect includes balance disorders. While on Earth, receptors in the inner ear allow humans to sense direction and gravity; however, in space, humans do not receive similar signals, which cause balance and posture to become disoriented. Symptoms, such as flatulence, puffiness of the face, weight loss, nasal congestion, and slight insomnia are other commonly experienced minor conditions that result from microgravity. After prolonged exposure to microgravity, some astronauts’ immune systems weaken and become extremely susceptible to illness due to a decreased amount of infection-fighting cells. The symptoms of the syndrome include nausea, headache, sweating, and exhaustion. One of the more serious effects of weightlessness includes fluid redistribution. Normally, due to the downward tug of gravity that exists on Earth, bodily fluids abound in the lower part of the body. When these bodily fluids shift from the lower part of the body to the upper body and head, fluid redistribution occurs. Accompanied with redistribution of fluids comes fluid loss. When the brain senses an increased volume in the upper body, the brain also interprets an increase in the total volume of fluid in the body. Finally, the brain responds by triggering the excretion of fluids, which generally results in dehydration. Another negative physiological consequence of weightlessness that occurs is the effect that zero-gravity has on the cardiovascular system. On Earth, the heart must operate against gravitational pressure to sustain blood flow. Under zero-gravity conditions, the force does not exist, causing the heart to lessen its pace. If this occurs over a long period of time, the heart shrinks. Upon return to Earth, the heart will have a tough time operating normally against gravity until it has readapted. Furthermore, bone deterioration, as a result of exposure to zero-gravity, remains extremely adverse to an astronaut’s health. Bone deterioration occurs when the amount of physical stress on bones decreases. Because stresses stimulate bone formation and increase bone density, the absence of the stress of gravity causes demineralization to take place. Similarly, muscle loss occurs as a result of weightlessness. Because the absence of gravity causes actions and movement to require less exertion, astronaut’s muscles become deconditioned and muscle atrophy occurs. Due to life in microgravity, the human body also decreases its production of red blood cells, resulting in a condition known as ‘space’ anemia. While ‘space’ anemia has not been life threatening, scientists are concerned about how anemia negatively affects crew performance. With vast amount physiological effects that could possibly occur, life science researchers and astronauts have had to create and utilize as many precautions as possible. The simplest countermeasure to the potentially detrimental effects of microgravity is arduous exercise. By rigorously exercising, astronauts address and combat two of the main adverse effects of prolonged exposure to microgravity: bone and muscle deterioration. Stressing muscles and bones with strenuous exercise can make up for some of the absence of the stress of gravity and fight weakening. Possible future countermeasures include the creation of artificial gravity in space. Two possible methods of generating gravity in a space ship exist. One way is to use a high speed of rotation and a short spin arm. Although this method remains cost efficient, it contains many drawbacks due to humans’ inability to tolerate high speeds of rotation without experiencing discomfort. Another drawback with this design is the gravity gradient that is created when a short spin arm is used. A gravity gradient remains present when the pull of simulated gravity at one point is different than the pull at another point; because of this, people may “literally be lightheaded because their head will weigh less than their lower body”. The second method, utilizing a long spin arm and slow rotation, remains superior because humans experience no discomfort, allowing a better environment in which to research and experiment; however, this method is extremely costly and time consuming. These drawbacks further create difficulty for life science researchers and astronauts when it comes to finding a solution to the problem of astronauts’ health in microgravity. Although methods of simulating Earth’s gravity are tremendously expensive, something effective must be done to counter the negative physiological effects of life in microgravity if long-duration space exploration should continue to occur. In order to counter the potentially deleterious physiological effects of living in microgravity most efficiently, time and money should be rendered to construct artificial gravity that will enable astronauts to discover new knowledge in a virtually harmless environment. Also, programs, such as NASA’s Biomedical Research and Countermeasures, or BR&C, Program, remain highly important to determine the health status of astronauts and take the most effective precautions in order to prevent their physiological deterioration. These programs also require much time, research, and money. Indeed, space exploration immensely benefits all of mankind, and the amount of inspirations and innovations that have resulted greatly outweigh the negative aspects. Time and money are necessary sacrifices that must be made in order for humankind to continue to benefit from space exploration without sacrificing human life. The benefits of space exploration include some of the most widely used technological innovations of today. Although space exploration has immensely benefited the entirety of mankind, hindrances, such as negative physiological effects of long duration exposure to microgravity, still block astronauts from discovering all that space exploration has to offer. As life science researchers continue to experiment with microgravity and living organisms, astronauts come closer to fully defeating all of the harmful physiological effects that can occur during space exploration. Someday, humans will have no problem enduring life in microgravity for long periods of time.
Works Cited "Artificial Gravity." 2000. 21 May 2008 Name: Niki R.
ProgramYear: 2008 Submit Date: May 22, 2008 Review Date: Jun 3, 2008 
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