What type of physiological problems the astronauts undergo after spending a long period in the weightless condition?

The human body, which has evolved under the condition of gravity, cannot endure prolonged weightlessness without adverse effects, the most serious one of which is depletion of calcium from the bones. For example, all the astronauts of one of the missions of NASA’s space laboratory named Skylab had lost 7% calcium through urine, although they were in space for only 84 days. In another case, one Russian astronaut had lost quite significant 15% calcium after spending 237 days in the space. 

In 1987 when the Russian astronaut Vladimir Titov was sent to replace Yuri Romanenko who had spent the recording period of 300 days aboard the space station Mir, he was categorically instructed not to embrace Romanenko or shake his hand vigorously because Romanenko’s bones might have become too brittle to withstand such exuberance. This apprehension of the Russian physiologists turned out to be true as the subsequent physical examination of Romanenko showed that his bones had lost as much as 18% calcium.

Another adverse impact of the prolonged weightlessness had been observed on the muscles of the astronauts. Since the legs do not have to bear the body weight, they run the risk of becoming atrophied, i.e., losing flesh, muscle, and strength, etc. due to the lack of their main function in the space, viz. bearing the weight of the body. The physiologists of NASA found that the astronauts returning to Earth after spending a long period in Skylab had not only lost the muscle power of their legs by 25%, but their legs had shrunk by 11%. Similarly, the muscles of the heart’s left ventricle had lost elasticity by about 10% because the heart was not required to struggle against gravity. The astronauts had even lost about 10% of the total quantity of blood during their prolonged stay in the space.

Biological reasons of these adverse side effects of a prolonged stay in the space have not been fully revealed yet, but one thing is quite clear: The astronaut’s body mechanism slips into a low-gear, and their body starts shedding or wearing away its own capacity which had become superfluous in the weightless state. And these physiological and anatomical changes manifest themselves in the form of the above mentioned adverse effects.

As science continues to study the behavioral changes taking place in astronauts, NASA has come out to find something quite surprising. NASA determined that it is quite evident that behavioral issues are bound to take place when groups of people are crammed in a small space for longer periods. Even though the crew chosen for expeditions undergo tough and thorough training, the effects are still obvious.

This is why the crew that will be sent to Mars will be provided even more thorough training in addition to preparation and scrutiny since they will be staying there for a longer period. Astronauts can expect changes in moods, morale, cognition, and interpersonal interaction. They might develop sleeping disorders due to 38 extra minutes each day on Mars in addition to noisy small environment and the stress of confinement or prolonged isolation situation. As a result, depression will occur. Fatigue will develop due to heavy shifting and workload schedules. 

Changes in interpersonal interaction will create miscommunication between colleagues, which will directly affect the mission and its success percentage. Boredom will creep in. Lack of fresh food and deficiency in variety will further contribute to cognitive and psychological decrements. Lastly, the morale and motivation will be deeply affected if not all, simply because the longer humans are kept in an isolated situation, the higher are the chances of developing cognitive, behavioral, and psychiatric disorders.

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