In space for 9 months, this is what happens to human body on return to earth – The Tribune

After an extended stay in space, astronauts returning to Earth undergo dramatic physical changes as their bodies readjust to gravity.

As NASA astronauts Sunita Williams and Butch Wilmore, along with Russian cosmonaut Aleksandr Gorbunoy, prepare to return to earth on Wednesday aboard SpaceX’s Dragon spacecraft, they will face several challenges brought on by prolonged weightlessness.

It may be fascinating to watch astronauts float inside the International Sapace Station (ISS), but the absence of gravity takes a toll on the human body over time. Upon return, astronauts frequently experience dizziness, nausea, and difficulty walking as they struggle to recalibrate to earth’s gravitational pull. For this reason, astronauts are often seated immediately after landing to prevent potential falls or injuries.

One of the key factors behind these symptoms is the vestibular system located deep inside the ear, which helps maintain balance. In microgravity, the brain receives conflicting signals from the vestibular organs, leading to space sickness. When astronauts return to earth, they sometimes experience ‘gravity sickness,’ which includes dizziness, vertigo, and instability.

Another striking impact of microgravity is fluid redistribution in the body. In space, without gravity pulling bodily fluids downward, astronauts’ faces and upper bodies swell, giving them a ‘puffy’ appearance. Upon return, they often suffer from orthostatic hypotension, or dizziness when standing, as their bodies struggle to regulate blood circulation against earth’s stronger gravity.

Additionally, prolonged exposure to weightlessness causes severe bone density loss. NASA reports that astronauts lose about one per cent of their weight-bearing bone mass per month in space if they do not exercise rigorously. To counteract this, astronauts aboard the ISS follow a strict two-hour daily exercise routine, using treadmills and resistance equipment to maintain muscle and bone health.

Other effects

Astronauts returning from extended space missions often report surprising changes, including softening of the soles of their feet—a condition known as ‘baby feet’. Without the pressure of walking, the thick skin on their feet peels off, making them unusually soft and sensitive.

Their immune systems also take a hit. According to the European Space Agency (ESA), immune cells behave differently in space, making astronauts more vulnerable to infections upon their return. However, no severe infections have been reported aboard the ISS so far.

Perhaps one of the strangest reported effects comes from Canadian astronaut Chris Hadfield, who noted a peculiar sensation in his tongue after spending months in space. “Right after I landed, I could feel the weight of my lips and tongue, and I had to change how I was talking,” he said, realising he had unknowingly adapted to speaking with a ‘weightless’ tongue in microgravity.

Road to recovery

Reacclimating to earth after months in space is no small feat. Astronauts undergo months of rehabilitation to regain muscle strength, improve coordination, and recalibrate their vestibular systems.