NASA's stranded astronauts may suffer these devastating effects once they return to Earth

NASA astronauts Sunita Williams and Barry Wilmore will soon return to Earth after an eight-day trip to the International Space Station (ISS) ended up lasting over nine months.

As a result of technical issues, Sunita ‘Suni’ Williams and Barry ‘Butch’ Wilmore will return home on Tuesday (18 March) on board a SpaceX Crew Dragon craft, which arrived at the ISS on Sunday.

However, their unexpectedly long stint in space may have long-term impacts on their health. Baylor College of Medicine's Center for Space Medicine has explained the profound ways “the human body changes in space” as well as some of the potential health challenges the two astronauts face.

This comes as Elon Musk gave an update about his plans to land humans on Mars as soon as 2029. Speaking to his followers on X on Saturday (15 March), the tech billionaire said: "Starship departs for Mars at the end of next year, carrying Optimus.

"If those landings go well, then human landings may start as soon as 2029, although 2031 is more likely."

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Bones

When gravity is reduced, which happens in a weightless environment such as space, the body no longer has to support its own weight.

This can cause muscles and bones, especially the ones in the legs, hips and spines, to be used less, which can lead to a loss of bone density. This process also leads to an increase in the mineral content elsewhere, leading to problems like increased urinary calcium and kidney stones.

Muscles

Both Williams and Wilmore have kept active during their time in space. If astronauts don’t maintain an active routine, their muscle mass can deplete as a result of not having to use their muscles to move around.

Because of this, muscles can start to weaken, which is why astronauts on the ISS have a strict exercise regime.

The heart is a cardiac muscle and is the main organ of the cardiovascular symptom. Although this system functions well in space, the heart could be affected by changes such as reduced blood volume. The British Heart Foundation says, “both the shape and size of the heart can change in microgravity” and “studies say the heart becomes almost 10 per cent more spherical after long periods of weightlessness in space.”

Neurological

Once the astronauts return to Earth, they must readjust to the planet's gravity. The brain receives and interprets information from the eyes, the inner ear's vestibular organs, and the muscles and joints but when in space, this data is different to what the brain is used to on Earth.

Astronauts returning to Earth might experience issues standing, stabilizing their gaze, turning and walking. "For their safety, returning astronauts are often placed in a chair immediately upon return to Earth,” the Baylor College of Medicine says.

Eyes

One of the most known issues related to the eyes as a result of space travel is Space-Associate Neuro-ocular Syndrome (SANS) which causes swelling in the back of the eye.

Mental health

Factors such as being in a small space and the loss of Earth’s 24-hour day cycle could lead to fatigue and stress while on a space trip. And now, the astronauts will have to get used to living on Earth upon their return.

A study published in the National Library of Medicine about the future of space exploration and the impact on astronaut mental health says humans in a spaceflight program could face, "symptoms of emotional dysregulation, cognitive dysfunction, disruption of sleep-wake rhythms, visual phenomena and significant changes in body weight, along with morphological brain changes."

The researchers add these symptoms "are some of the most frequently reported occurrences during space missions".

Radiation

Here on Earth, the atmosphere shields us from harmful space radiation. But beyond Low Earth Orbit (LEO), astronauts face significant risks such as radiation sickness, nervous system effects, degenerative diseases, and an increased risk of cancer, according to NASA.

"In low earth orbit where the ISS is, astronauts are at least partially protected by the magnetosphere that protects Earth from the radiation exposure of deep space," Dr. Rihana Bokhari told ABC News in September. Dr. Bokhari is acting chief scientific officer at the Translational Research Institute for Space Health at Baylor College of Medicine.

"However, they do have a greater radiation exposure than those on Earth because the ISS passes through areas of trapped radiation in their orbit," she added. "Butch and Suni, since they are on the ISS, will not be exposed to enough radiation to seriously cause large impacts on body systems but the long duration exposure to greater radiation than on Earth could lead to an increase in the risk of cancer."

You should also read:

'Alien' spotted on board ISS as stranded astronauts prepare for return to Earth

NASA's 'stranded' astronauts respond to Elon Musk's claim he offered to get them home early

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