Challenges to the human body in Deep Space

New Delhi: NASA astronauts Sunita Williams and Butch Wilmore are all set to return to Earth couple of hours from now after spending nine months aboard the International Space Station (ISS) for a mission that was supposed to last just eight days.

Bone and muscle deterioration, radiation exposure, vision impairment : These are just a few of the challenges space travellers face on long-duration missions, 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, which can put them at a greater risk of cancer and damage to vital organs over time and even impact their neurocognitive functions.

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 towards the brain which can cause several life-threatening complications. This includes complications like decreased blood pressure, increased heart rate, dizziness, fluctuation in body temperatures, dehydration, swelling of the face, shock, 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 and the future of space exploration.

ISS missions typically last six months, but some astronauts stay up to a year, and 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, even those who go into space just for a few days, as 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 which involves changes in vision, including 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, as it passes through the Van Allen radiation belt, but 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.

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. Narresh Purohit-MD, DNB, DIH, MHA, MRCP(UK), is an Epidemiologist, and Advisor-National Communicable Disease Control Program of Govt. of India, Madhya Pradesh and several state Health organizations.    He’s  the Principle Investigator – Association of Studies In Behavioural Science),                 Dr. Purohit is also Advisor-National Mental Health Program .