|Space Travel 101: Fundamentals of Space Travel|
Being with the same people in a cramped up place for long periods of time can be extremely stressful. Tension between crewmates can accumulate, increasing the risk of miscommunication and other mishaps. In addition, the stress of isolation may damage the immune system’s ability to fight infectious diseases.
Traveling with a small crew isolated from the rest of the world for long periods of time often causes heightened anxiety, boredom, depression, loneliness, excessive fear of danger, and homesickness. Manned missions require crews to spend large amounts of time in close proximity. Because space is extremely limited aboard a spacecraft, privacy is often unavailable. Longer missions, such as to Mars, take roughly six months just to get to there. During long missions, crews become easily irritated and often withdraw. As a result, tension between crewmates often builds, and the risk of miscommunication and other mishaps occurring increases. Researchers have suggested that an all female crew may be best, because females tend to be more tolerant of their companions. However, females are more at risk for bone loss (see osteoporosis).
Although problems between the crew may not occur, the feeling of isolation from the rest of Earth may be detrimental to the immune system. Research has shown that the stress of isolation may damage the body’s ability to fight infectious disease. Studies in Antarctica indicate that those isolated individuals have a decline in T-cells, the immune system's "killer cells". In a small capsule high in space, hypochondria becomes more common, as astronauts have felt they were suffering from diseases that doctors could not diagnose.
Although the psychological effects of space travel are often not considered an eminent danger in space travel, its presence is very evident in some cases and should not be neglected.