Wilmore and Williams Splash Down
US astronauts Barry “Butch” Wilmore and Sunita “Suni” Williams have returned to Earth after spending over nine months in space. They undocked from the International Space Station (ISS) early Tuesday morning and are set to splash down later today, marking the conclusion of their extended mission.
Microgravity’s Impact on the Human Body
Spending prolonged periods in microgravity affects the human body in multiple ways. Muscle atrophy, bone density loss, and vision changes are among the most common issues astronauts face. While some of these effects are reversible, others may persist for years or even remain permanent.
Figure 2: Space’s effect on the human body
Muscle Atrophy and Bone Loss
Microgravity weakens muscles over time, making astronauts more susceptible to muscle loss the longer they remain in space. Professor Shenhav Shemer from the Technion – Israel Institute of Technology states that long-duration space missions lead to more severe muscle atrophy.
NASA astronauts follow strict exercise routines, averaging two hours of physical training daily to counteract muscle deterioration. However, even with regular workouts, atrophy still occurs. Williams may experience greater muscle loss than Wilmore due to physiological differences, including lower baseline muscle mass, hormonal changes, and metabolic shifts.
NASA research indicates that weight-bearing bones lose between 1% and 1.5% of their mineral density each month in space. The longer an astronaut stays in orbit, the greater the impact on their skeletal system.
Increased Risk of Kidney Stones
Bone density loss leads to increased calcium levels in the bloodstream, raising the risk of kidney stone formation. Baylor College of Medicine states that astronauts face a higher likelihood of developing kidney stones due to excess urinary calcium. Without proper management, this condition can cause severe pain and health complications.
Recovery Timeline Varies
Wilmore and Williams initially planned for a short mission lasting just over a week. A brief stay in space would have caused only minor, completely reversible effects on muscle and bone mass. However, their extended mission increases the risk of metabolic and physiological changes that may not fully reverse.
Shemer explains that muscle recovery timelines vary. Some muscles regain pre-flight mass within a year, while others may take two to four years. Recovery depends on factors such as age, overall fitness, and individual physiology.
Astronauts Temporarily Grow Taller
Microgravity causes spinal discs to expand, making astronauts temporarily taller. When NASA astronaut Scott Kelly returned to Earth after nearly a year aboard the ISS, he was approximately two inches taller than when he launched.
However, this effect is short-lived. Within two days of returning to Earth, Kelly’s height returned to normal as gravity compressed his spine back to its usual form.
Also Read: Crew-9 Astronauts Begin Journey Home After Prolonged ISS Stay
Vision Changes Due to Fluid Shift
Microgravity causes bodily fluids to shift toward the head, increasing pressure inside the skull and affecting the eyes. This phenomenon can lead to vision problems, a condition known as Spaceflight Associated Neuro-ocular Syndrome (SANS). NASA reports that more than 50% of astronauts experience at least one symptom of SANS during their missions.
To counteract these effects, NASA uses compression cuffs worn around the legs. These devices help redistribute fluids and reduce pressure buildup in the head.
Coordination and Balance Challenges
Returning to Earth’s gravity after months in space presents significant physical challenges. Astronauts often struggle with coordination and balance due to disruptions in proprioception, the body’s ability to sense its position and movement.
NASA provides immediate support upon landing, often seating astronauts in chairs to help them adjust to Earth’s gravity. The process of regaining full coordination can take days or weeks, depending on the individual.
Sense of Smell and Taste Restored
Microgravity affects not only muscles and bones but also astronauts’ senses. Garrett Reisman, a former NASA astronaut who spent 95 days in space, explains that fluid shifts dull the sense of smell and taste.
Upon returning to Earth, astronauts quickly regain these senses. “I remember as soon as we opened the hatch of the space shuttle, I got my first whiff … it just smelled great,” Reisman told CNN.
Mission Recovery Begins
Wilmore and Williams will now undergo an intensive rehabilitation program to help their bodies readjust to Earth’s gravity. NASA will closely monitor their recovery, using their experience to improve future spaceflight missions.
Long-duration space travel presents unique challenges to the human body. Data from returning astronauts will help scientists develop better countermeasures to protect future crew members on extended missions, including those planned for the Moon and Mars.
