Norishige Kanai
Japanese astronaut Norishige KanaiReuters/Kirill Kudryavtsev

Japanese astronaut Norishige Kanai, who is on a mission to the International Space Station and claimed that he had grown 9 cm (3.5 inches) while in space, has apologised for spreading faking news. He had earlier expressed his concerns about whether he will be able to safely return to Earth or not.

The 41-year-old had taken to Twitter to inform people about the scenario. "We had our bodies measured after reaching space, and wow, wow, wow, I had actually grown by as much as 9 centimetres (3.5 inches)!" Norishige Kanai had tweeted.

"I have grown like a plant in just three weeks. Nothing like this since high school. This makes me a little worried that I might not be able to fit in the Soyuz seats for our return," he added.

This is a known phenomenon that astronauts "grow" during the space missions because their spines extend in the absence of gravity, but the gains are generally limited to a couple of centimetres and disappear once they are back on the ground. But in this case, it was quite unusual raising a number of questions.

"Nine centimetres is a lot, but it is possible, knowing that every human body is different," Libby Jackson of the UK Space Agency had told BBC News.

"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."

However, on Wednesday, Norishige Kanai apologised saying that he had measured himself after his captain raised questions about the unusual growth and found out that he had stretched only 2 cm from his Earth-bound height.

"This mis-measurement appears to have become a big deal, so I must apologise for this terrible fake news," he tweeted. He, however, did not explain how the original miscalculation occurred.