The Effect of Space Travel on The Human Body
For over 50 years, humans have been exploring space. In 1957, the Soviet Union launched the world’s first artificial satellite into space, called ‘Sputnik 1’. Since then, we’ve landed on the moon, created the International Space Station, and nowadays, there’s talk of sending humans to mars in just a decade. Innovation has no end, but apart from the advancements in technology, organisations such as NASA must also take into consideration, the massive effect space travel has on the human body.
Space travel affects the human body both physically and mentally. One of the most well-known consequences of space travel is the weakening of bones. Throughout your life, your bones are broken down by large cells known as Osteoclasts. An Osteoclast is a large multinucleate bone cell which absorbs bone tissue during growth and healing. Osteoblasts are different cells that counter this action, and help build new bone. Throughout one’s life, these processes are balanced out, but that changes when an astronaut enters space, and survives in microgravity. Since their bones do not support as much weight, and they aren’t subjected to the same stresses as they would be on earth, the calcium in the bones is broken down and released into the bloodstream, reflecting a decrease in bone density.
Scientists believe that the body breaks down bones much faster than it builds them up, in microgravity. The bone density of an astronaut can decrease by as much as 1% every month during space travel. Even after returning to Earth, one’s bone loss might not be corrected by rehabilitation. This leads to an increase in the chances for their bones to get fractured upon returning to Earth. Due to the change in gravity upon return, many astronauts find it difficult to even walk, and many have broken their bones soon after. Astronauts are also more likely to have kidney stones due to dehydration, and the release of calcium from their bones.
There’s also bad news for an astronaut’s muscles, particularly the ones in their legs and their back. This is because of the significant decrease in their use. Exercise can help prevent this, but one study found that even with exercise, muscle strength as well as muscle volume, can still decrease.
Without Earth-like gravity, astronauts can also have vision problems. Researchers studied 27 astronauts who spent an average of 108 days in space, and observed that about 22% of them showed flattening of the back of the eyeball. The heart is also negatively affected, as it can potentially lose mass and become spherical in shape, causing a decrease in blood pressure when an astronaut returns to Earth.
NASA has also learnt that behavioural issues among groups of people crammed in a small space over a long time, no matter how well trained they are, are inevitable. Expedition crews selected for a stay aboard the space station are carefully chosen, trained, and supported to make sure they can work effectively as a team for six months. The types of problems they may encounter are a decline in mood, cognition, morale, or interpersonal interaction. Depression could occur, and fatigue is inevitable given that there will be times with heavy workload and shifting schedules.
The most dangerous aspect of space travel is space radiation. On the space station, astronauts receive over ten times the radiation than what’s naturally occurring on Earth. Our planet’s magnetic field and atmosphere protect us from harsh cosmic radiation, but without that, you are more exposed to the treacherous radiation. Above Earth’s protective shielding, radiation exposure may increase one’s cancer risk. It can damage one’s central nervous system, with both acute effects and later consequences, manifesting itself as altered cognitive function, reduced motor function, and behavioural changes. Space radiation can also cause radiation sickness that results in nausea, vomiting, anorexia, and fatigue. You could develop degenerative tissue diseases such as cataracts, cardiac, and circulatory diseases too.
NASA has identified these issues, and is working on reducing the negative impact of space travel on the human body. Even though millions dream of exploring space, one must understand that space travel requires sacrifice, endurance, and a strong will. This information definitely increases the respect we have for astronauts in our minds.
– Ayushmaan Aashish Kher