Going to space is an exciting but scary prospect - surely you can't spend all that time out there without worrying the whole time about whether you'll be able to make it home.
CHECK OUT THE MOMENT KANAI WENT TO SPACE BELOW:
That's the plight of one Japanese astronaut currently aboard the International Space Station (ISS) who claimed he had grown so much he's worried he won't be able to make the trip back.
Since arriving on the ISS in December as part of Expedition 54, Lieutenant Norishige Kanai, a doctor and astronaut for Japan's national space agency JAXA, said he had stretched by 9cm in height.
He also said - perhaps not entirely seriously - that he might not be able to fit into the cramped space of the Soyuz capsule which is set to carry him back to Earth at the end of his expedition.
"Good morning, everybody," Kanai posted on social media. "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, Kanai has since admitted he was wrong, saying that he had actually grown by 2cm. He blamed "a measurement mistake", and apologised for spreading 'fake news'.
"I'm very sorry for tweeting out such fake news," he tweeted in Japanese.
If Kanai had grown by the extent he originally claimed, it could have been a big problem. The capsule carrying astronauts back to Earth is a tight squeeze, with the space inside it being small and strictly regulated.
It's not unusual for astronauts to grow - or more technically, stretch - while they're in space, but the speed and extent of Kanai's growth is unusual, as people in space usually grow no more than a few centimetres in height.
This 'growth' is caused by astronauts' spines stretching out due to the reduced gravity in space. Because their vertebrae aren't being bunched together as tightly as they are on Earth, they can suddenly float apart, leading to the change in height.
Although much of the extra height is gained when astronauts first enter space, the growth spurt tends to slow down over time. Growing 9cm in just a few weeks, as Kanai claimed to have done, is very rare.
Potential astronauts shouldn't consider retiring and starting a new career in basketball when they return to Earth though. The height change is only temporary as people shrink back to their usual size once they're back on Earth and again subject to the planet's gravity.
Hopefully Kanai will be able to make it back down. Thankfully he doesn't have to worry about it yet - there's still five months of Expedition 54 to go.
Featured Image Credit: PA