NASA Astronauts Return to Earth After 9 Months: How Space Changes the Body

On March 19, 2025, NASA astronauts Sunita “Suni” Williams and Barry “Butch” Wilmore returned to Earth after spending nine months in space – far longer than their planned eight-day mission. Their extended stay highlights the harsh physical and mental toll of space travel on the human body.

🚀 A Mission That Lasted 9 Months Instead of 8 Days

Williams and Wilmore, along with Roscosmos cosmonaut Aleksandr Gorbunov, were part of a mission aboard the Boeing Starliner Calypso. Launched on June 5, 2024, they were initially scheduled for an eight-day stay on the International Space Station (ISS). However, due to a malfunction in the spacecraft’s thrusters, NASA decided to keep them on the ISS while working on a safe return plan.

After 288 days in space, they finally returned to Earth aboard the SpaceX Dragon spacecraft. The capsule splashed down off the coast of Florida at 5:57 pm local time (21:57 GMT) on March 19, 2025.

🌌 How Does Space Impact the Human Body?

Spending months in microgravity severely affects the body. Here’s how prolonged exposure to space takes its toll:

🦴 1. Muscle and Bone Loss

In the absence of gravity, astronauts’ muscles and bones weaken.

• Muscle atrophy: Without the need to support body weight, astronauts rapidly lose muscle mass. Despite exercising for two hours a day, six days a week, muscle loss still occurs.
• Bone loss: Microgravity causes astronauts to lose about 1% of their bone mass per month, making their bones fragile and more prone to fractures.

☢️ 2. Radiation Risks

Even though the ISS is partially protected by Earth’s magnetosphere, astronauts still face significantly higher radiation exposure.

• Six months in space exposes them to 10 times the radiation they would experience on Earth.
• This increases the risk of cancer, cognitive decline, and other long-term health issues.

🩸 3. Fluid and Blood Changes

• Astronauts lose around 20% of their body fluids and about 5% of their body mass while in space.
• Blood circulation slows, and red blood cell production decreases, which can lead to fatigue and anemia.
• Cardiovascular issues like cardiac arrhythmia are common.

👁️ 4. Vision and Eye Problems

Microgravity affects astronauts’ vision.

• Fluids shift upward, putting pressure on the eyes, which can impair vision.
• Exposure to space radiation also increases the risk of cataracts.

🧠 5. DNA and Cognitive Effects

• Around 7% of astronauts’ DNA remains altered even after they return to Earth.
• Prolonged radiation exposure can cause brain damage and increase the risk of neurodegenerative diseases, such as Alzheimer’s.

🛡️ 6. Weakened Immune System

• The immune system weakens in space, making astronauts more susceptible to infections.
• Skin becomes thinner, tears more easily, and heals slower.

🌍 How Does the Body Recover After Returning to Earth?

Even after astronauts land, their bodies take time to readjust. Here’s how recovery happens:

✅ First Few Days:

• Astronauts experience balance issues, dizziness, and weakened cardiovascular function.
• Blood pressure starts to normalize, and flatulence (which is common in space) is no longer a problem.

✅ One Week Later:

• Symptoms like motion sickness and disorientation disappear.
• Sleep patterns return to normal.

✅ Two Weeks Later:

• The immune system recovers, and lost body fluids are replenished.
• Red blood cell production returns to normal levels.

✅ One Month Later:

• Muscles regain strength and return to nearly pre-flight levels.

✅ Three Months Later:

• Skin redevelops, and body mass returns to normal.
• Any vision problems caused by fluid shifts in space are typically resolved.

✅ Six Months Later:

• While most bodily functions recover, astronauts remain at a higher risk of bone fractures and cancer.
• 93% of their genes return to normal, but 7% remain disrupted.

🌠 The Future of Space Travel and Human Health

As space agencies and private companies aim for longer missions, including trips to Mars, understanding the effects of long-term space travel on the human body is crucial. Developing better countermeasures, such as advanced exercise equipment, protective shielding, and medical treatments, will be essential to ensure astronaut health and safety on future deep-space missions.

🌎 Conclusion

The nine-month mission of Williams and Wilmore is a reminder of the immense physical and mental challenges astronauts face. Despite the risks, their journey provides valuable insights that will help pave the way for safer and longer space missions in the future.

Reference from:-https://www.aljazeera.com/news/2025/3/19/nasa-astronauts-return-to-earth-how-does-space-change-the-human-body