A JAPANESE astronaut has grown almost nine centimetres during his time in space, prompting fears he may not be able to travel back to Earth as he is too big for his seat.
Japanese astronaut Norishige Kanai travelled to the International Space Station (ISS) three weeks ago, and during that time he has had and astonishing growth spurt.
He now says that he is concerned that he will be unable to fit into the seat of the Russian Soyuz vehicle which was meant to return him to Earth in June.
When astronauts are in zero-gravity environments, they tend to grow between two and five centimetres.
This is down to the fact that, free from the shackles of Earth’s gravity, their vertebrae in their spine begins to separate and elongate.
For Mr Kanai however, the effects have been too much as his body has lengthened by an astonishing nine centimetres (3.5 inches).
For reference, when NASA astronaut Scott Kelly returned from the ISS after a year long stint, he had grown by just five centimetres (two inches).
The Japanese astronaut wrote on Twitter: “Good morning, everybody. I have a major announcement today. We had our bodies measured after reaching space, and wow, wow, wow, I had actually grown by as much as 9cm!
“I grew like some plant in just three weeks. Nothing like this since high school.
“I’m a bit worried whether I’ll fit in the Soyuz seat when I go back.”
However, when Mr Kanai does return to Earth, he will return to his normal height.
Libby Jackson of the UK Space Agency told BBC News: “Nine centimetres is a lot, but it is possible, knowing that every human body is different.
“You do get taller in space as your spine drifts apart, usually by about two to five centimetres.
“There’s a range of growth for different people, and everybody responds differently.”