TOKYO (Reuters) – Japanese astronaut Norishige Kanai, on a mission to the International Space Station, apologized on Wednesday for saying he had grown 9 cm (3.5 inches) while in space and expressing concern about whether he’d be safe on his return to Earth.

Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) during the send-off ceremony after checking their space suits before the launch of the Soyuz MS-07 spacecraft at the Baikonur cosmodrome, in Kazakhstan, 17 December 2017. REUTERS/Kirill Kudryavtsev/Pool/File Photo

Most astronauts “grow” during protracted space missions because their spines extend in the absence of gravity, but the gains are usually limited to a couple of centimeters (inches) maximum and disappear once they are back on the ground.

The 41-year-old Kanai, who went to space last month for a nearly six-month mission, posted on Twitter on Monday that he had “a big announcement.”

“My height’s been measured here in space and somehow, somehow, I’ve grown 9 cm! In only three weeks I’ve really shot up, something I haven’t seen since high school,” he tweeted.

“This makes me a little worried that I might not be able to fit in the Soyuz seats for our return.”

But a bit over a day later – and in the wake of a flurry of news stories – he apologized, saying that he’d measured himself after his captain raised questions about the apparent growth and he had stretched only 2 cm from his Earth-bound height.

“This mis-measurement appears to have become a big deal, so I must apologize for this terrible fake news,” he tweeted, without explaining how the original miscalculation had occurred.

“It appears I can fit on the Soyuz, so I’m relieved.”

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