Lengthy Space Trip Alters Human Body

"When astronauts Sunita Williams and Barry Wilmore returned to Earth on Tuesday after spending nine months on the International Space Station, their bodies had undergone significant changes.

The SpaceX capsule carrying the astronauts splashed down off the Florida coast around 6 p.m. ET Tuesday. The pair were supposed to spend eight days on the station, but a malfunctioning spacecraft left them stranded without a ride home until now.

Many astronauts' bones never fully recover, according to a 2022 study in the journal Scientific Reports. Often, astronauts must wear prescription glasses upon their return. And, for a time, they will be taller. When astronaut Scott Kelly returned home in 2016 after spending almost one year in space, he had gained 2 inches in height.

Weightlessness also causes body fluids to shift from astronauts' legs toward the center of their bodies.

In November, concerns were raised online about the health of Williams, whose face appeared gaunt in several images. Williams said that a fluid shift and additional muscle she had built in space changed the way she looked.

"There is a lot of changes that go on up here. I think there is some rumors going on that I'm losing weight," Williams said during a Nov. 12 interview with New England Sports Network. "I'm the same weight that I was when I got up here."

The space station orbits about 250 miles above the Earth's surface, putting its occupants at a slightly higher risk of exposure to harmful space radiation.

Astronauts wear radiation-detecting devices called dosimeters to check how much radiation each of them has received during time on the station. Once astronauts, over their careers, reach a certain level of exposure, the National Aeronautics and Space Administration bars them from returning to space.

NASA doctors will be checking astronauts for signs of cancer for the rest of their lives.

Astronauts exercise on board the station to help lessen some of these physiological problems, and each astronaut responds differently to the rigors of space.

After landing, Williams and Wilmore were taken to NASA's Johnson Space Center in Houston, where NASA doctors checked their vital signs and tested them for short-term illnesses and potential long-term health effects.

Then, they will go through a 45-day recovery program that includes two hours a day of exercise, medical and performance testing, and scientific tests, according to NASA.

"Generally, most crew members' physiological systems recover within this time frame," NASA said Monday.

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WHAT HAPPENS

THIS NINE-MONTH sojourn will have made them taller, weaker and maybe given them vision trouble, according to medical studies of previous astronauts.

Growing Taller

Astronauts get taller in space because the disks of the spinal column expand in weightlessness.

Smaller Heart

The heart doesn't work as hard in space, which could lead to a decrease in its size. Back on Earth, a smaller and weaker heart could overextend itself.

Weaker Bones and Muscles

For every month in space, astronauts' weight-bearing bones become roughly 1% less dense while their muscles lose tissue.

Poor Vision

During long-duration missions, the eyes become flatter and vision changes.” [1]

1.  Lengthy Space Trip Alters Human Body. Niiler, Eric.  Wall Street Journal, Eastern edition; New York, N.Y.. 20 Mar 2025: A9.