While the three inches he's gained have put him at around six feet tall, the Russian Soyuz TMA Descent Module is created to fit astronauts of up to six foot three inches, meaning that Kanai still has a little more growing room before he'd struggle to fit.
Aboard the Russian rocket are Russian cosmonaut Anton Shkaplerov, U.S. astronaut Scott Tingle, and Japanese astronaut Norishige Kanai. "Since coming to space, I have grown 9 centimeters".
He is a member of the International Space Station expedition 54/55 of the Japan Aerospace Exploration Agency (JAXA).
"Growing" in space is not an unusual phenomenon as most astronauts "grow" during protracted space missions because their spines extend in the absence of gravity. I grew like some plant in just three weeks, nothing like this since I was a junior high school student. "As a matter of fact, the tightness I had in my shoulders is gone so I'm pretty certain I did not grow 9 cm". Upon returning to earth and its gravitational pull, astronauts return to their usual height.
He joked: "This makes me a little anxious that I might not be able to fit in the Soyuz seats for our return".
What's rare is the rate and amount Lt Kanai has grown in three weeks of living on the space lab. He further expressed his concern about whether he'd be able to adjust back upon his return to Earth.
"There's a range of growth for different people, and everybody responds differently".
Thankfully, with a growth of only two centimetres, he would be well below the 191-centimetre limit.
Kanai will be landing back on Earth in a Soyuz spacecraft within the next six months.
After an influx of media interest-and questions from his captain-Kanai made a decision to remeasure himself to find out how tall he had actually become. Time in which he could grow even taller.