What challenges Sunita Williams will have to face now, she may feel dizzy, experience gravity sickness, acclimatization process may take weeks

While it may seem fun to see astronauts floating inside the International Space Station (ISS), the effects of weightlessness can have long-lasting impacts on their bodies after returning to Earth. Astronauts often face challenges such as nausea, dizziness, and difficulty walking and speaking. This could likely be the case for NASA astronauts Sunita Williams and Butch Wilmore, as well as Russian astronaut Alexander Gorbunov, who recently returned to Earth aboard SpaceX's Dragon spacecraft.

Many astronauts from various missions have reported experiencing difficulties like trouble walking, vision problems, dizziness, and a condition colloquially known as "baby feet" upon their return. "Baby feet" refers to the thick skin on the soles of astronauts' feet peeling away, resulting in softer skin akin to that of a child's. 

According to the Baylor College of Medicine in Houston, upon returning to Earth, astronauts must quickly readjust to gravity, which can lead to challenges in standing, stabilizing their vision, walking, and turning. To facilitate this adjustment, astronauts are often seated immediately after landing.

Acclimatization process

The acclimatization process can take several weeks. The vestibular organ in the inner ear helps maintain balance by sending information about gravity to the brain. The Japanese space agency JAXA explains that the low gravity environment in space alters the information received from these organs, which can confuse the brain and lead to space sickness—a common issue for space travelers. Upon returning to Earth, astronauts may experience gravity sickness, which has symptoms similar to space sickness.

In space, gravity causes bodily fluids to collect in the upper body, leading to a swollen appearance. JAXA notes that astronauts often feel dizzy upon standing due to a condition known as orthostatic hypotension. This occurs because the stronger gravitational pull on Earth makes it more challenging for blood to circulate from the heart to the head.

Decrease in bone density

Additionally, the lack of gravity results in a significant and often irreversible decrease in bone density. NASA states that if astronauts do not take preventive measures, the density of weight-bearing bones can decrease by about one percent per month while in space. To combat this, astronauts on the ISS follow a strict exercise regimen, requiring two hours of daily exercise on a treadmill or stationary bicycle to maintain bone and muscle health. Without this exercise, astronauts may struggle to walk or stand after months of weightlessness.

Difficulty speaking

Canadian astronaut Chris Hadfield shared that upon his return from the ISS in 2013, he experienced difficulty speaking due to the weightlessness of his tongue in space. He noted, "Immediately after returning to Earth, I could feel the weight of my lips and tongue, and I had to adjust my way of speaking. I hadn't realized I had become accustomed to talking with a weightless tongue."

Moreover, astronauts face an increased risk of infection and disease due to a weakened immune system after returning to Earth. Therefore, Sunita Williams, Butch Wilmore, and Alexander Gorbunov will need to take extra precautions for their health as they readjust to life on the ground.