International Space Station (ISS) – NASA astronauts Sunita Williams and Butch Wilmore, who have been stranded in space far longer than planned, may face significant physical challenges upon their return to Earth next week. Originally set for an eight-day mission, their stay aboard the ISS unexpectedly stretched to nine months due to technical difficulties.
NASA’s Crew-10 is scheduled to enter the ISS on Sunday, March 16, after launching from the Kennedy Space Center in Florida aboard the Falcon 9 rocket on Friday, March 14.
Baby feet: A painful return to gravity
One of the immediate effects Williams and Wilmore are likely to experience is a condition known as “baby feet,” where the soles of astronauts’ feet become soft and highly sensitive after a prolonged time in space. The absence of gravity means there is no resistance or friction on their feet, causing the hardened skin to wear away, leaving the soles tender and vulnerable. Until their feet build up calluses again—a process that can take weeks or even months—walking could be an uncomfortable and even painful experience.
Bone density loss: An irreversible effect of microgravity
In addition to baby feet, prolonged exposure to microgravity leads to a significant reduction in bone density. According to NASA, astronauts can lose approximately one percent of their weight-bearing bone density per month if they do not engage in rigorous exercise to counteract the effects. The deterioration is often irreversible, making long-duration space travel a serious concern for future missions to Mars and beyond. Muscles, which are normally engaged through everyday movement on Earth, also weaken in space due to the lack of physical exertion.
Blood volume and circulation challenges
The cardiovascular system also undergoes significant changes in space. The heart does not have to work as hard to pump blood against gravity, leading to a reduction in overall blood volume. This can cause circulation issues, including clot formation due to slower blood flow in certain areas of the body. Fluid distribution also shifts in microgravity, leading to swelling in the head and upper body. This accumulation of fluids can alter the shape of the eyeballs, contributing to vision impairment—one of the reasons many astronauts wear corrective lenses after extended space travel.
Radiation exposure: A silent but serious threat
One of the most concerning risks astronauts face in space is radiation exposure. Unlike Earth, where the planet’s magnetic field and atmosphere provide a protective shield, astronauts in space are exposed to dangerous levels of cosmic radiation. NASA identifies three main sources of radiation exposure for astronauts: particles trapped in Earth’s magnetic field, solar energetic particles from the Sun, and high-energy galactic cosmic rays from deep space. Extended exposure to these forms of radiation increases the risk of cancer, cataracts, and other long-term health complications.
As Williams and Wilmore prepare for their long-awaited return to Earth, their physical recovery will be closely monitored by NASA’s medical teams.