Space Exploration Day| What happens to our body in space?
Prolonged exposure to microgravity in space causes significant physical changes to the human body, including muscle atrophy and loss of bone density. Astronauts require extensive rehabilitation upon returning to Earth to readjust to gravity.
Why it matters
As long-duration space missions become more common, understanding the physiological toll on the human body is critical for astronaut health and mission planning.
When astronauts Sunita Williams and Butch Wilmore returned to Earth after spending nine months on the International Space Station due to a technical issue aboard the Boeing Starliner in March 2025, the pair took time to readjust to the Earth’s gravitational pull on their bodies, requiring extensive rehabilitation. If nine months sounds like a long time, consider this: two Russian astronauts — Oleg Kononenko and Nikolai Chub — broke the record for the longest stay on the ISS, spending a total of 374 days in orbit, before returning to Earth in September 2024. Of course, astronauts are rigorously trained to cope with the rigours of space travel. Even so, the prolonged stay in microgravity can significantly alter the human body. Here’s how it does.
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