Since the two-hour excursion into space by Yuri Gagarin in 1961, manned space travel has caught the attention of scientists, entrepreneurs, and entertainers alike. For more than five decades, NASA's Human Research Program (HRP) has studied the effects of space travel to the human body. Scientists use what they learn to design devices, procedures, and strategies to keep astronauts safe and healthy throughout their space missions.
What exactly happens to the body in space and what are the risks? Here are five things that may happen to the human body after prolonged exposure to the space environment.
Space Sickness
Here on Earth, we are strongly affected by the force of gravity and our bodies are designed to respond to this force. Humans have a small organ known as the vestibular organ located deep inside our ears. This structure plays an important role in keeping our bodies balanced. The vestibular organ converts information on gravity and acceleration experienced by the human body into electrical signals and sends them to the brain.
Outside the Earth, the force of gravity is much weaker, so the information received from the vestibular organ changes. This can confuse the brain as it adjusts its interpretation of the vestibular interpretation, leading to 'space sickness'.
This condition does not persist for very long, as it can go away if a person stays for a few days in space. There are also individual differences in the severity of space sickness, and some people do not experience it at all.
Swollen Face
While on Earth, a person's blood and bodily fluids are pulled by gravity into the lower portion of their body. Gravity weakens when they go to space, which means that the bodily fluids are no longer pulled down. As a result, these fluids are accumulated in a person's upper body.
Swelling of the face is not the only effect of accumulated fluids from weak gravity. Inside the nose, the mucous membranes also swell, so astronauts often experience nasal congestion. However, staying in space for a while balances the fluids in the body, so facial swelling usually disappears after a few weeks.
READ ALSO: Astronauts Acquire Mental, Emotional Health Problems During Space Missions Due to Lack of Gravity
Weak Bones and Muscles
Here on Earth, we are always using the muscles of our lower body without being really conscious of resisting gravity. In space, a person can maintain posture without standing on their legs and there is no need to use their legs to move about.
As a result, a person's bones and muscles, particularly in the legs and lower back, weaken after staying in space for a long time.
Radiation Exposure
Humans and everything on Earth are protected from space radiation by the planet's magnetic field and atmosphere. Still, every one of us is exposed to low levels of radiation every day, from the food that we eat to the air that we breathe.
In space, astronauts are exposed to increased levels of radiation which are different from those on Earth. Major sources of space radiation include galactic cosmic rays, solar energetic particles from the Sun, and particles trapped in Earth's magnetic field.
Humans exposed to radiation on Earth show increased risk of cancer and degenerative diseases. Meanwhile, health risks for astronauts from radiation exposure are primarily driven by long-term impacts.
Stress From Isolation and Confinement
The International Space Station has more living space than earlier versions of spacecraft. Still, the scope for activity is limited compared to life on Earth. During space missions, astronauts have to live and work together in a cramped space, and they may develop stress before even realizing it.
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