Japanese astronaut apologises for saying he grew 9cm after three weeks in space

Japanese astronaut Norishige Kanai said on Twitter that he was 9 centimetres taller since arriving at the International Space Station on December 19. "Good morning, everyone. Today I share some serious news. Since coming to space, I have grown 9 centimetres. This is the most I've grown in three weeks since junior high school," Kanai wrote Monday.

But just 24 hours later, Kanai has said that in fact, he grew by just two centimetres and that he was sorry for his initial tweet. Most astronauts do "grow" during protracted space missions because their spines extend in the absence of gravity, but it's usually just a couple of centimetres. Kanai tweeted that his Russian commander on the ISS, Anton Shkaplerov, was sceptical, "so I quickly measured myself and was roughly 182cm. 2 cm plus my height on earth," The BBC reports.

NASA has said about two inches of growth is typical and expected in space. While it is temporary, and astronauts return to their normal height when they slip the bonds of space and return home, the height difference has an immediate impact on the dimensions of space suits, stations and vehicles.