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
Sunita Williams and Butch Wilmore (File Pic/AFP)
NASA astronauts Sunita Williams and Butch Wilmore are all set to return to Earth after spending nine months aboard the International Space Station (ISS) for a mission that was supposed to last just eight days.
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Spending a considerable amount of time in space can pose several health risks, some of which were well-documented as the two astronauts navigated these challenges.
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.
In a previous interaction with mid-day.com, Dr Atul Narayankar, Consultant Medical Oncologist, Wockhardt Hospitals, Mira Road, had highlighted how different elements in space can affect health, saying, “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.”
Further explaining the changes one’s body undergoes in space, he had said, “One’s muscles and bones 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.
Exercise key
Despite the attention their mission has received, Williams and Wilmore’s nine-month stay is "par for the course," Rihana Bokhari, an assistant professor at the Center for Space Medicine at Baylor College, told AFP.
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.
Most people know that lifting weights builds muscle and strengthens bones, but even basic movement on Earth resists gravity, an element missing in orbit. To counteract this, astronauts use three exercise machines on the ISS, including a 2009-installed resistance device that simulates free weights using vacuum tubes and flywheel cables, reported AFP.
A two-hour daily workout keeps them in shape. "The best results that we have to show that we're being very effective is that we don't really have a fracture problem in astronauts when they return to the ground," though bone loss is still detectable on scans, Bokhari further said.
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," Emmanuel Urquieta, vice chair of Aerospace Medicine at the University of Central Florida, told AFP.
Another challenge is "fluid shift" -- the redistribution of bodily fluids toward the head in microgravity. This can cause various health issues, including vision impairment.
Dr Smit M. Bavariya, Cataract Surgeon at Dr. Agarwal's Eye Hospital, Wadala, in a previous interaction with mid-day.com had stated, “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, explained astrophysicist Siegfried Eggl.
"Shielding is best done with heavy materials like lead or water, but you need vast quantities of it," Eggl told AFP.
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, reported AFP.
(With inputs from AFP)
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