Astronauts Sunita Williams and Barry Wilmore were supposed to spend only days in space, rather than nine months. This article explores how radiation and altered gravitational forces affect the human body during their extended stay.
There was significant discussion regarding the possible health hazards faced by the marooned NASA astronauts Barry "Butch" Wilmore and Sunita "Suni" Williams during their time in space. Upon returning to Earth in March 2025 following an unforeseen stay of nine months aboard the International Space Station (ISS), their systems would have adapted to exposure from radiation and weightlessness.
The impact of radiation and microgravity affects all astronauts similarly—beginning with symptoms like nausea and puffy faces—but their assignment was intended to span just one week. This raised the query: Could these impacts potentially be more severe for Suni and Butch?
In June 2024, Williams and Wilmore found themselves marooned aboard the International Space Station (ISS) after their Boeing Starliner capsule encountered technical issues en route. It was considered too risky to return them using the same faulty craft. Prior to this mission, which spanned from 2024 to 2025, both had accumulated extensive experience with multiple trips into space totaling several hundred days each. Given that the Starliner launch was part of a test flight, they would have undergone rigorous preparation and training for such an emergency situation.The requirements needed to become an astronaut.
Humans have not naturally adapted to survive in space—specifically, in environments devoid of Earth’s protective atmosphere and under conditions of negligible gravity. Consequently, individuals venturing into space require extensive specialized training along with rigorous health supervision preceding, throughout, and following their journeys.
Astronauts chosen for human spaceflights are deemed competent not just in performing their designated tasks but also in handling complex and evolving scenarios.
Wilmore and Williams served as test pilots. The initial manned mission of Boeing's Starliner spaceship To the ISS. However, propulsion problems with their spaceship caused an extension of their planned eight-day mission. Consequently, they became part of the routine crew, referred to as SpaceX Crew 9.
Shortly after being marooned, former German astronaut Thomas Reiter stated that he believed it would be quite challenging for them, yet he was confident that they could manage the situation.
Reiter embarked on two space missions; his initial one was aboard Mir, a Soviet-era space station that had its orbit decayed in 2001. He later worked as a flight engineer on the International Space Station (ISS). Williams took over Reiter’s position during her inaugural trip to space.
"They both have experience; they are well-versed in the procedures aboard the ISS," stated Reiter.
One of the greatest hazards of space travel is radiation.
Space agencies allocate dedicated sections to investigate how space impacts the human body—the German Aerospace Center (DLR), for example, operates a research facility called :envihab located near Cologne.
In June 2024, the magazine Nature has published over 40 studies referred to as the "most extensive collection of data in the field of aerospace medicine and space biology" to date.
One of the studies was called TWINS. This study included 10 laboratories that conducted comparisons. Astronaut Scott Kelly, who spent nearly one year aboard the ISS in 2015 , along with his identical twin Mark, who is also an astronaut but remained on Earth. It is this particular study that highlights one of the primary dangers associated with extended time spent in space—radiation exposure.
"Space radiation exposure will likely be the major constraint on astronaut performance and their duration in space," stated Susan Bailey, a radiation biologist at Colorado State University. Bailey headed the investigation within the TWINS study focusing on how radiation impacts telomeres—small protective structures found at the ends of human chromosomes.
"Exposure to radiation can be extremely harmful to our DNA," stated Bailey.
Such exposure heightens the risk of cancer for astronauts. Additionally, it boosts oxidative stress within their bodies.
What this is all about is protecting them from severe long-term consequences and immediate risks," Bailey stated. "We must develop protective measures so we can safeguard astronauts throughout their time in space, as well as when they might be stationed on the Moon or possibly Mars.
Space agencies set particular caps on the level of radiation astronauts may encounter over their careers.
Weightlessness: From Kidney Stones to Blurry Vision
In microgravity conditions of space, bones can become weaker due to mineral loss; astronauts typically experience a decrease in bone density by about 1-1.5% for each lunar cycle they spend in orbit.
This might also result in alterations of the mineral levels within the body. result in health risks For instance, elevated amounts of calcium within the body’s urinary system, responsible for eliminating waste products like urine, may result in the formation of kidney stones.
"When they return, they are unable to join the dance floor just like anyone else who has spent many months in zero gravity," Reiter stated.
This environment can also cause changes to vision, with fluids in the body shifting to the head and putting pressure on the eyes.
Extended pressure may result in Spaceflight Associated Neuro-ocular Syndrome, potentially causing permanent changes to the eye’s focusing capability.
After returning to Earth, both Williams and Wilburn will undergo routine health checks.
There is ample food and water available on the ISS.
Even though traveling to space poses significant health hazards, these concerns are outweighed by the effective fulfillment of pressing requirements through the use of the ISS.
"If suddenly there are two additional people, they won’t run out of water, oxygen, or food right away," Reiter stated.
Food, water, oxygen supplies, and carbon filtration requirements are consistently maintained through resupply missions.
There are six dormitories, two restrooms, and a gymnasium—plenty of space for everyone to have their own area.
Additionally, psychological support has been enhanced by involving long-term astronauts in the continuous operations aboard the ISS.
Wilmore and Williams promptly became engaged in scientific and supportive tasks alongside their fellow astronauts.
"Astronauts aspire to go to space; they dedicate their entire lives to this purpose." They might have believed that getting marooned in space would be “quite magnificent,” as Bailey stated.
Edited by: Zulfikar Abbany
Sources:
Space Omics and Medical Atlas (SOMA) Across Orbits (Nature, 2024) https://www.nature.com/immersive/d42859-024-00009-8/index.html
Human health risks (NASA) https://www.nasa.gov/hhp/human-system-risks/
What Is Spaceflight-Associated Neuro-Ocular Syndrome? (NASA, 2021) https://www.nasa.gov/image-article/what-spaceflight-associated-neuro-ocular-syndrome/
The aerospace medicine research center: envihab in Cologne (DLR) https://www.dlr.de/en/me/research-and-transfer/research-infrastructure/envihab-cologne/
The article was initially published on August 20, 2024, and has been updated as of March 17, 2025.
Author: Matthew Ward Agius