NASA astronauts Sunita 'Suni' Williams and Barry 'Butch' Wilmore are just days away from returning to Earth after months on the International Space Station.
They'd only been scheduled for a mission of a few days up in space, but that was back in June 2024 and they're still up there.
Barring another unfortunate hiccup in the equipment set to bring them home, they're scheduled to leave the ISS on Wednesday (19 March) and will finally make it back to the confines of our planet.
Advert
This means they won't have been the people in space the longest, that record is held by Oleg Kononenko and Nikolai Chub who spent 374 days in space, but they'll have long since passed the usual six month stints astronauts assigned to the ISS are there for.
Once they return, Williams and Wilmore face a period of rehabilitation that is likely to last at least six weeks as their bodies get used to being in gravity once more.
It's that lack of gravity which causes all sorts of problems for the human body when it's time to return to Earth.
Advert
NASA reckons that for every month in space, an astronaut's bone density drops by about one percent, and since your muscles don't need to work as hard to hold you up they atrophy.
All in all, someone who has been up in space for a prolonged period of time as Williams and Wilmore have been are going to be physically weaker when they're back on Earth as the bones and muscles that held them up aren't as strong as they used to be.
Space also makes your heart weaker as, without gravity, it doesn't have to work quite so hard to pump blood around your body.
Advert
Human beings are creatures that are used to living with gravity, our bodies as we know them are working through the constant and steady force of Earth's gravity so when it's removed things start getting weird.
The way other fluids move through the body while in space is also affected by the lack of gravity.
Astrophysicist Alan Duffy told The Guardian that being in space for a long time makes someone feel like they've got a 'constant cold' as fluid builds up in their head and doesn't drain properly, though apparently the impairment to smell is a blessing as the ISS is said to stink something rotten.
Advert
On the bright side, returning to Earth will soon clear this feeling of a cold up, but while they were in space this fluid will also have changed the shape of their eyeballs and weakened their vision.
For some astronauts, this returns to normal after a while but others need glasses for the rest of their lives.
As if that wasn't bad enough, being in space exposes the body to radiation which can cause permanent DNA damage. An experiment involving twins found that the one sent up to space mostly recovered the damage after six months but that some genes had been permanently changed.
So they'll certainly be feeling the effects upon their return.
Joe Harker