It’s hard to believe how Sergei Krikalev was feeling when he returned to planet earth on 25 March, 1992.

The cosmonaut spent 311 days aboard the Mir space station, in orbit from 1986 to 2001.

It was supposed to be a routine mission lasting five months, but things took an unexpected turn.

As a result, Krikalev had to stay at the station for ten months due to him no longer having a country, which was double the length of time he was supposed to be there.

The reason being, money had dried out in what was once the newly independent Kazakhstan, so Sergei knew that the financial means required to bring him back wasn’t there.

He said while on Mir: “The strongest argument was economic because this allows them to save resources here.

“They say it’s tough for me – not really good for my health. But now the country is in such difficulty, the chance to save money must be top priority.”

Although some of the astronauts managed to make it back during the time he was up there, Krikalev also didn’t want to jeopardise the actual mission.

Ten months on, Krikalev’s replacement was sent to Mir so that he could finally come home.

In a 2015 interview with The Guardian, he explained what was going through his mind on returning to earth.

He said: “It was a long process and we were getting the news, not all at once, but we heard about the referendum, for example.

His extended mission was not part of the plan (Getty Images/NASA)

“I was doing my job and was more worried about those on the ground – our families and friends – we had everything we needed.

“I think I felt satisfaction that I had done my job, and done it well. The second one was a sort of relief as I had held a huge responsibility for many months.”

Krikalev valued his time in space and has logged more than 800 days aboard the International Space Station, Mir space station, Soyuz spacecraft, and the space shuttle.

“You start to understand that in many cases, our separation on Earth is more artificial,” he said in an interview with NASA.

Rubio returned to Earth on 27 September, 2023 after racking up a grand total of 371 days in space.

Spending so long unshackled from the mortal confines of our planet resulted in a number of changes to his body, as time in space changes a person in more ways than one.

Rubio was actually supposed to be on his mission for six months, but the time he spent in space got doubled and it made him a prime example of what the effects of living gravity-free for such a long time looks like.

We Earthbound people with no access to spaceships might not even be able to comprehend what this could be like.

The lack of gravity causes a decrease in muscle mass and even bone loss within just the first couple months of a mission – let alone the year Rubio spent up there.

At the time of the NASA astronaut’s landing, Dr Jennifer Fogarty, chief scientific officer at Baylor College of Medicine’s Translational Research Institute for Space Health, told ABC News: “How do you coordinate movement like walking, which you haven’t done for a long period of time, and then the idea of balance?

“When you put those two together, it can kind of create a little bit of a precarious situation and something that’s very well-monitored with the crew members when they land on Earth.”

Once back on Earth, he noticed quite the change. (APHOTOGRAFIA/Getty Images)

The expert also added that the longer the time in space goes on for, the longer the time it takes for the astronaut to reacclimatise when they get back.

Plus when living in space, an astronaut’s blood flow can be heavily affected.

This can cause symptoms including blurred vision or eye swelling due to something known as Spaceflight Associated Neuro-Ocular Syndrome.

According to the co-director of the Center for Aerospace Physiology at Case Western Reserve University School of Medicine, Dr Michael Decker, our veins have handy-dandy valves in them to make sure ‘blood doesn’t flow backwards when we stand up’.

And being enclosed in a weightless room for a long period of time will certainly impact the body’s blood flow.

He added: “Some of this increased intracranial pressure can actually impact the eye and lead to visual impairment.

“Sometimes when astronauts land, that visual impairment does not necessarily resolve.”

He took some time to get back to his best. (NATALIA KOLESNIKOVA/AFP via Getty Images)

Rubio’s mental and physical health will have been assessed while he was in space and in January, he explained that he’d spent the past four months ‘reincorporating [himself] back into Earth’.

“You adapt incredibly quickly to being in space, but then unfortunately, the readaptation process back to earth can sometimes be a little bit longer and more difficult.” he told TIME.

“And that’s just, I think, because the forces of gravity and the forces at play here on Earth tend to have a stronger effect on your body. So it takes two to three months to get yourself back to where you were pre-flight. I’m feeling pretty normal.”

He added: “At this point, I feel like I’m back to 90-95%. So lots of exercise, lots of testing, and science.”

While Rubio holds the American record, if you’re wondering who the all time record holder for being in space is, that goes to Valeri Polyakov who between 1994 and 1995 spent a whopping 437 continuous days in orbit.