Astronauts Butch Wilmore and Suni Williams spent nine months aboard the International Space Station (ISS), experiencing the extreme effects of long-duration space travel. Their return to Earth was marked by immediate physical challenges, including being placed in wheelchairs due to muscle and bone deterioration. What was initially meant to be an eight-day mission turned into a 286-day ordeal, exposing their bodies to the harsh realities of microgravity and space radiation.
While their journey is not the longest on record—Russian cosmonaut Valeri Polyakov holds that distinction with 14 months in space—it was long enough to reveal the significant toll space travel takes on the human body. From accelerated ageing to weakened immune systems, prolonged exposure to space presents obstacles that scientists must address before deep-space missions, including those to Mars, become a reality.
How Space Affects the Body
Accelerated Ageing
One of the most noticeable effects of long-duration space travel is how rapidly the body weakens. Without gravity, the heart and blood vessels do not have to work as hard to pump blood, leading to gradual cardiovascular weakening. Bones also lose density at an alarming rate, decreasing by 1-2% each month. This increases the risk of osteoporosis and fractures once astronauts return to Earth.
Muscle atrophy is another major concern. Since movement in space requires minimal effort, muscles begin to shrink due to lack of use. Upon return, astronauts often struggle to walk, stand, or even balance properly. Despite using specialized treadmills, exercise bikes, and resistance bands aboard the ISS to combat these effects, Wilmore and Williams still suffered significant physical deterioration.
Cosmic radiation exposure adds another layer of risk. Space radiation causes oxidative stress and DNA damage, leading to premature ageing at the cellular level. Over time, this can contribute to increased risks of cancer, cardiovascular disease, and other health complications.
Impaired Vision and Increased Brain Fluid
Microgravity does more than just weaken bones and muscles—it also impacts the eyes and brain. Fluids in the body, which are normally pulled downward by Earth’s gravity, shift toward the head in space. This excess fluid buildup puts pressure on the brain and eyes, leading to a condition known as Spaceflight-Associated Neuro-ocular Syndrome (SANS).
Symptoms of SANS include optic nerve swelling, flattening of the eye’s shape, and folds in the retina. These changes can lead to blurred vision, headaches, and, in some cases, permanent eyesight damage. While fluid levels normalize after returning to Earth, the lasting effects on vision remain a concern for long-term astronauts.
