NASA astronauts Sunita Williams and Butch Wilmore returned to Earth after spending nine months aboard the International Space Station (ISS). The mission was originally supposed to last just eight days. Bone and muscle deterioration, radiation exposure, and vision impairment are challenges faced by space travellers on long missions. This is even before considering the psychological toll of isolation.
When travelling outside Earth’s protective atmosphere, astronauts are exposed to cosmic rays and solar energetic particles. These exposures can put them at a greater risk of cancer. There can also be damage to vital organs over time. Furthermore, such conditions may even impact their neurocognitive functions in space.
MUSCLES BECOME WEAK
The changes one’s body undergoes in space, includes one’s muscles and bones that tend to become weaker, causing distress. The fluids present in the body, such as blood, start to shift upward. They move towards the brain. This movement can cause several life-threatening complications. This includes complications like decreased blood pressure, increased heart rate, and dizziness. It also causes fluctuations in body temperatures and dehydration. Additionally, there can be swelling of the face and shock. Other risks include respiratory distress, weakness, changes in vision, and sleep apnea.
As space technology advances, there’s a need to create innovative solutions to safeguard the health of astronauts. These innovations also ensure the future of space exploration.
ISS missions typically last six months in space. However, some astronauts stay up to a year. Researchers are confident in their ability to maintain astronaut health for that duration.
A two-hour daily workout keeps astronauts in shape.
Other Health Challenges:
Apart from this, balance disruption can also be an issue. This happens to every single astronaut. It occurs even with those who go into space just for a few days. They work to rebuild trust in their inner ear.
Another challenge is “fluid shift” — the redistribution of bodily fluids toward the head in microgravity. This can cause various health issues, including vision impairment.
Spaceflight Associated Neuro-ocular Syndrome (SANS) is a condition that involves changes in vision. These changes include blurred vision, difficulty focusing, and changes in the shape of the eye. It is caused by increased intracranial pressure, which results from fluid shift in microgravity and affects the optic nerve and the eye’s structure.
Managing Radiation:
Radiation levels aboard the ISS are higher than on the ground. This is because it passes through the Van Allen radiation belt. However, Earth’s magnetic field still provides significant protection. The shielding is crucial, as NASA aims to limit astronauts’ increased lifetime cancer risk to within three percent. However, missions to the Moon and Mars will give astronauts far greater exposure in space.
Artificial gravity, created by rotating spacecraft frames, could help astronauts stay functional upon arrival after a nine-month journey to Mars. Alternatively, a spacecraft could use powerful acceleration and deceleration that matches the force of Earth’s gravity. That approach would be speedier — reducing radiation exposure risks — but requires nuclear propulsion technologies that don’t yet exist.
(Dr Naresh Purohit is Executive Member- Indian Society of Aero- Space Medicine. The views expressed are tat of the author)
