NASA astronauts Butch Wilmore and Suni Williams have recently returned from a demanding nine-month mission on the International Space Station (ISS). However, they may face an even greater challenge now.

Individuals who have traveled to space, such as the UK’s first astronaut, Dr. Helen Sharman, have described an experience that profoundly alters their lives. The effects that space travel has on astronauts beyond their physical health upon re-entry into Earth’s atmosphere are not as widely discussed.

Even though the physical health issues astronauts encounter upon returning to Earth are well-documented, the long-term impact of their space missions on their overall well-being remains underreported.

Known as ‘overview effect’, it’s a term coined in the late 80s but known about since the first years of space travel to describe how astronauts returning to Earth are often unable to view their everyday lives in the same way as they did before.

Those who experienced it include some of the most famous names in space history, including Yuri Gagarin, Michael Collins and Sally Ride – and say only fellow astronauts can truly know what it feels like. 

Dr Sharman, who was 27 when she made history on May 18th, 1991 as the first British astronaut to go into space, as part of the Soyuz TM-12 mission, says her own short eight-day mission completely ‘reset’ how she viewed her home life. 

The Imperial College London academic told MailOnline: ‘After I returned to Earth, I realised that what I had not once thought about in space was the material things that I owned or aspired to own.

‘It was my family, friends and colleagues living in places I could see as I looked down on Earth who I remembered. Being in space reset my life priorities, and that has remained with me ever since.’

Tough journey still ahead: NASA astronaut Suni Williams is helped out of a SpaceX Dragon spacecraft as she arrives back on earth after nine months on March 19th

Williams fellow astronaut Butch Wilmore (pictured) has suffered physical symptoms during his exile in space – but the ‘overview effect’, where returning astronauts struggle with mental health after being in space, could now kick in  

The term ‘overview effect’ was first coined in the late 80s and describes how Earth-returners often make major life changes after struggling to adapt to normal life once more. (Pictured Sunita Williams and Butch Wilmore pictured stranded at the International Space Station before their return)

Canadian astronaut Robert ‘Bob’ Thirsk now regularly speaks about the huge impact his two stints in space, in 1996 and 2009, have had on what he values in life at the Kennedy Space Center Visitor in Florida. 

The retired astronaut says he no longer cares for politics, particularly on a local level, because it feels insignificant when you’ve seen the Earth from so far away. 

The 71-year-old says his wife still tells him that his head ‘is still in space’ because of the major impact that the trips have had on him. 

Family and friends can feel alienated, he says, by the extraordinary shared experiences astronauts have with their fellow space explorers, and are left feeling like they can’t ever match what they experienced together.

He also says the ‘overview effect’ has left him hugely concerned for the planet, and that his main message now is preserving it for future generations. 

Dr Sharman says that looking back on our planet from so far away can evoke different and complex feelings when people return home.

She says:  ‘For some, seeing the bright Earth against the backdrop of the vast expanse of black space can increase our awareness of the fragility of Earth; for others it is more a sense of attachment – after all, Earth is where all known life exists.

‘I remember how obviously interconnected everything seemed: swirls of plankton in ocean currents, flashes of lightning that appear to set off flurries of other flashes many miles away, and rivers crossing numerous borders before they disgorge into the sea.’

Suni Williams with her husband Michael before her journey to ISS – returning to Earth can spark life changes, says Britain’s first astronaut Dr Helen Sharman

Canadian astronaut Robert ‘Bob’ Thirsk now regularly speaks about the impact his two stints in space have had on his life at the Kennedy Space Center Visitor in Florida. Right: Dr Sharman, who was 27 when she went to made history as the first British astronaut to go into space says she ‘reset’ how she viewed life upon her return

The Canadian astronaut, now 71, says his wife tells him he left his head in space and is frank about how the shared experience with his fellow astronauts can alienate friends and family

The Sheffield-raised retired astronaut also discussed the process Butch Wilmore and Suni Williams are currently in as they adapt to life back on Earth. 

Dr Sharman said: ‘Normal life resumes in a controlled and gentle way for astronauts, especially those who have spent many months in space. 

‘We see the Earth-returners being pulled out of the spacecraft and they disappear from public view for a while, but after the initial medicals and other checks, there will be weeks of debriefings of one sort or another, managed time with friends and family (and pets), and monitored physical exercise. 

Gradually, the astronauts become more self-determining. But we never forget the amazing views from orbit.’ 

As Williams, 59, and Wilmore, 62, emerged from their SpaceX Crew Dragon capsule yesterday, medical teams rushed to help them onto stretchers.

Months spent in low gravity cause fluid shifts in the body which can cause health problems ranging from ‘chicken legs’ to vision loss 

Sunita Williams and the rest of the ISS crew performed Olympic events on the space station last summer but will now face weeks of physical rehabilitation

This is a normal procedure for astronauts returning from space since their weakened muscles make it difficult to walk under the force of Earth’s gravity.

The pair will now undergo several days of intensive medical checks at NASA’s Johnson Space Center in Houston but health experts have already noticed signs of physical decline in the stranded astronauts.

And even while they were on the ISS, experts expressed concern over the pair’s gaunt appearance and apparent weight loss.

To help the astronauts overcome these long-term impacts, NASA has a specialised rehabilitation program for people returning from space.

Examinations begin as soon as they exit the capsule before they are flown to their crew quarters at NASA’s Johnson Space Center in Houston for several more days of routine health checks.

NASA astronauts who return from long ISS missions complete a 45-day rehabilitation program that requires them to exercise for two hours per day, seven days per week.

The program is tailored to the specific needs of each astronaut, according to NASA.