Astronauts return to Earth after longest ISS stay – this is how they found it

Three astronauts have returned to earth after living on the International Space Station for more than a year.

Russian cosmonauts Oleg Kononenko and Nikolai Chub, as well as Nasa astronaut Tracy Dyson, have headed back to earth on the Soyuz space capsule, which landed in Kazakhstan.

The Russians have broken the record for the longest stay on board the ISS, at 374 days in total.

Tracy had spent about six months on the ISS, and the bell for her departure was rung by Suni Williams, another Nasa astronaut currently stranded on the space station after arriving there on a Boeing Starliner.

Oleg also holds the record for the longest cumulative time spent in space, racking up an impressive 1,111 days in orbit during five trips.

But as the astronauts get used to earth’s gravity and return to normality, the impact living in low-gravity upon the human body was immediately clear.

Oleg, Nikolai and Tracy all had to be carried out of the spacecraft after it landed in the Kazakhstan Steppe, due to the toll their time in orbit had taken on their bodies.

Tracy was seen sat in a wheelchair with a blanket over her legs after being lifted from the capsule, while staff wiped her face with a cloth.

As astronauts are spending longer and longer stretches in orbit, research into the impact of low gravity on the human body is still in its early stages, the BBC reports.

To start, it’s difficult for astronauts to keep fit because they don’t need to use their muscles as much.

They undertake two-and-a-half hours of exercise and training on board the ISS every day in its ‘gym’, including squats, deadlifts, rows and bench presses, and eat diet supplements to try and keep their bones healthy – but even this isn’t enough.

Without gravity constantly affecting their bodies, muscle and bone mass quickly begins to diminish.

The worst affected are the muscles in our back, neck, calves and quadriceps, AKA the muscles which help us maintain our posture.

Muscle mass can fall by up to a fifth within two weeks, increasing to 30% on missions of three to six months in length.

Bone mass also falls, with astronauts losing 1-2% of their bone mass for every month they spend in space – compared to on earth where people lose bone mass at a rate of 0.5-1% each year.

This can increase their risk of fractures as their bones get weaker, and it can take up to four years for their bone mass to return to normal.

For the short kings out there, there’s hope yet as astronauts can actually grow a bit taller during their time in space, as their spines elongate thanks to the lack of gravity pulling it downwards.

However this does come with a risk of back pain and slipped disks once back on earth.

And the lack of gravity can also mess up astronauts’ eyesight, because gravity helps to force the blood in our bodies downwards while the heart pumps it back up again.

This process gets messed up in space, meaning blood can accumulate in the head more than usual, potentially pooling at the back of the eye and around the optic nerve.

This could cause oedema, which can lead to decreased sharpness in vision and structural changes in the eye itself. These changes start after just two weeks in space – but while some changes reverse after about a year back on earth, others can be permanent.

Seeing galactic cosmic rays and energetic solar particles without the protection of earth’s atmosphere can also damage their eyes.

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