Sunita Williams Splashdown | How India helped with space farming tests

Space travel presents unique challenges to the human body. Astronauts experience extreme physiological and psychological changes due to microgravity, radiation exposure, and prolonged isolation. Physiologist Dr William Selvamurthy explains the crucial experiments conducted aboard the International Space Station (ISS) and their implications for future space missions.

NASA and SpaceX have executed ground-breaking missions, extending astronaut stays from a few days to nearly nine months. "Kudos to the astronauts who adapted with resilience and psychological robustness," says Dr Selvamurthy. These extended missions provide valuable insights into how humans can survive longer in space and adapt to unexpected technological failures, such as propulsion issues or helium leaks.

Growing food in space

Food sustainability is a major concern for long-duration space missions. Astronauts are experimenting with aeroponics and hydroponics to grow fresh vegetables in space. "Aeroponics allows moisture in the air to support plant growth," explains Dr Selvamurthy. This research builds on earlier tests by ISRO and Indian universities, which have sent spinach cell cultures and germinating seeds to space.

These experiments aim to supplement astronauts’ diets, which primarily consist of pre-packaged meals. Fresh food could significantly improve long-term mission viability and astronaut health.

Also read: Sunita Williams returns: Science behind astronaut recovery, what India can learn

Understanding circadian rhythms

The absence of a regular day-night cycle in space disrupts the body’s natural biological clock. "All our bodily functions are linked to solar periodicity," says Dr Selvamurthy. Without natural light cues, astronauts rely on artificial lighting and structured schedules to regulate sleep and circadian rhythms.

By studying how astronauts adjust their sleep-wake cycles, scientists can develop better strategies to prevent fatigue and cognitive impairment during extended space missions.

Microbes and space survival

Microbes that survive in space undergo genetic and physiological changes, making them invaluable subjects for scientific study. "We collected microbial samples from the spacecraft to study their resilience in extreme environments," Dr Selvamurthy explains. Scientists aim to identify DNA expressions that allow microbes to thrive in space.

These findings could inform strategies to protect astronauts from harmful bacteria and develop better countermeasures against space-borne pathogens.

Also read: What NASA astronauts Sunita, Butch ate for nine months in space on ISS

Physiological challenges in microgravity

Astronauts face multiple physical stresses in space, including:

Microgravity effects: The absence of gravity affects blood circulation, bone density, and muscle strength.

Radiation exposure: Cosmic radiation poses long-term health risks, including increased cancer susceptibility.

Psychological challenges: Isolation, monotony, and claustrophobia contribute to stress and mental fatigue.

Dr Selvamurthy highlights the importance of cardiovascular adaptation. "Gravity helps regulate blood flow on Earth, but in space, blood rushes to the head, causing pressure changes and disorientation," he explains. This leads to fluid shifts, blood vessel dilation, and a sensation of heaviness in the head.

Muscle and bone loss

Prolonged space missions lead to muscle atrophy and bone mineral density loss. "Weight-bearing muscles, like those in the legs and spine, weaken due to disuse," Dr Selvamurthy notes. Studies show that astronauts can lose 1 per cent of bone mass per month in microgravity.

To counteract this, astronauts follow strict exercise routines, including isometric and resistance training. They also take calcium and Vitamin D supplements to slow bone loss. However, restoring full bone density after returning to Earth remains a challenge.

Also read: Effects of space travel on human body and rehab process: Dr Keith Siew explains

Psychological resilience

Mental well-being is just as crucial as physical health for astronauts. "Astronauts experience sensory deprivation, separation from family, and fear of the unknown," Dr Selvamurthy states. Psychological resilience plays a key role in overcoming these stressors.

Returning to Earth provides emotional relief, but astronauts still undergo psychological readjustment. "Seeing family members and celebrating their return helps restore their mental state," he adds. Studies continue to explore ways to improve astronaut mental health, including meditation and mindfulness practices.

Post-spaceflight recovery

The reconditioning process after a long space mission involves multiple phases:

Acute recovery (first 15 days): Astronauts are monitored for orthostatic intolerance (difficulty standing), cardiovascular issues, and muscle weakness.

Extended rehabilitation (45 days+): Muscle strength and bone density are gradually restored through physical therapy, exercise, and nutrition.

Neurological and balance recovery: The inner ear, responsible for balance, readjusts to Earth's gravity, reducing disorientation and dizziness.

"Astronauts are kept in a supine position initially to prevent blood pooling in the lower body," Dr Selvamurthy explains. This reduces the risk of fainting and cardiovascular stress as their bodies readjust.

Also read: 'Earth missed you': Modi welcomes Sunita Williams and Crew-9 on their return

India’s advancements in space medicine

As India prepares for its Gaganyaan mission, advancements in space medicine are crucial. "We need a rigorous selection process for astronauts, testing their physical, physiological, and psychological robustness," Dr Selvamurthy emphasizes.

Training for space survival

India has developed space analogue stations in Ladakh, where astronauts train under simulated space conditions. "These stations recreate the claustrophobic environment of space capsules," he explains. Training includes:

• Simulating low-gravity conditions
• Physical fitness programmes, including yoga and meditation
• Psychological conditioning to enhance mental resilience

Yoga and meditation have been recognized for their potential benefits in space missions. "Commander Rakesh Sharma practised yoga in space back in 1984," Dr Selvamurthy recalls. These techniques can help astronauts maintain focus, reduce stress, and improve overall well-being.

Also read: Dizziness, gravity sickness, weightless tongue, baby feet: What astronauts face back on earth

Future of space medicine

Looking ahead, space medicine will play a vital role in ensuring human survival on long-duration missions. Scientists are exploring new possibilities, such as:

• Developing vaccines in microgravity
• Enhancing astronaut nutrition with fresh-grown vegetables

Studying DNA changes to improve space resilience

"We are on the verge of exciting discoveries," Dr Selvamurthy concludes. With continued research and collaboration between ISRO and global space agencies, India is poised to make significant contributions to human spaceflight.

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