U.S. astronauts Barry "Butch" Wilmore and Sunita "Suni" Williams splashed back down to Earth on Tuesday after more than nine months in space. The astronauts, who arrived at the International Space Station (ISS) last June, were initially scheduled for a week-long stay, but thruster problems with their Boeing Starliner capsule forced them to remain in orbit for an extended period. Splashing down in a SpaceX Dragon capsule off the coast of Florida just before 6 p.m. ET on March 18, 2025, the pair are now tasked with recovery as they transition back to life on Earth.
Long-duration space missions carry inherent health risks, including muscle atrophy, bone density loss, and vision changes. The astronauts are expected to face these challenges head-on as they begin their post-mission medical evaluations at NASA's Lyndon B. Johnson Space Center in Houston, Texas. Their health concerns stem from physical changes caused by microgravity, which can lead to various complications upon returning to Earth.
Muscle atrophy is a significant side effect of long-term stays in space. According to Shenhav Shemer, a professor of biology at the Technion — Israel Institute of Technology, the longer an astronaut spends in microgravity, the more severe the muscle weakening. This is particularly critical for women, who are more susceptible to muscle loss due to lower baseline muscle mass and testosterone levels, as well as the hormonal changes they experience in the space environment.
NASA recommends that crew members engage in an average of two hours of exercise per day to help combat muscle and bone loss. However, even rigorous training may not completely prevent atrophy. Without Earth's gravity, astronauts experience an average loss of 1% to 1.5% of bone mineral density each month, particularly in weight-bearing areas such as the legs, hips, and spine. The consequences of this loss could be severe, potentially leading to fractures, osteoporosis, and other medical problems upon their return.
In an interesting observation, astronaut Scott Kelly, who spent nearly a year aboard the ISS, returned approximately two inches taller than when he left due to the expansion of spinal disks in microgravity. However, he quickly reverted to his original height within days of returning to Earth, highlighting the temporary nature of such changes.
Another critical concern for astronauts returning from long missions is vision health. Fluid shifts in microgravity can create pressure on the eyes, leading many astronauts to experience symptoms related to Spaceflight Associated Neuro-ocular Syndrome (SANS). NASA reports that over half of all crew members show one or more symptoms of this condition, which can result in long-term vision impairment.
Returning space travelers face challenges beyond muscular and visual disturbances. Proprioception, the body’s ability to sense its position and movement, can be significantly affected. This often results in coordination issues as astronauts re-adjust to gravity. Typically, upon landing, they may be assisted in movement and placed in chairs to help them gather their bearings.
Health impacts extend even to astronauts' skin and feet. Leroy Chiao, a former NASA astronaut, describes how the lack of weight-bearing on their feet while in space leads to softer skin on the soles, making astronauts susceptible to sensitivity upon returning to Earth, a condition he playfully refers to as “baby feet.” Meanwhile, astronaut Scott Kelly humorously noted how the sensitivity in his feet drew compliments after he returned home.
Moreover, some astronauts have reported skin rashes and sensitivity post-mission, attributed to the prolonged lack of skin stimulation in space. These symptoms have been documented and treated with medication, hydrotherapy, and self-care strategies upon their return.
As Williams and Wilmore process their return, they’ll spend several days in quarantine for medical evaluations to ensure their well-being. The process reflects NASA's commitment to astronaut health and readiness for future missions. As they prepare to re-integrate into life on Earth, the duo highlights the resilience required to endure the physical and psychological toll of extended space missions. Their experience serves as a testament to the challenges faced by astronauts as they brave the transition from microgravity back to gravitational pull—a journey that demands strength, adjustment, and care.
