Why did Thomas Pesquet grow a few centimeters in space?

Our colleagues from the daily Le Progrès come back to a strange phenomenon that affects astronauts after their return to Earth. Thomas Pesquet has indeed gained a few centimeters after his last stay aboard the international space station. And he’s not the only one that happens to.

Humans have indeed evolved to adapt to the conditions of our planet. To function normally our body therefore needs to feel gravity. On board the station, the astronauts and cosmonauts are in microgravity – a kind of perpetual free fall, allowed by the speed of the station placed in low orbit around the Earth. They must constantly exercise their muscles or they risk atrophy.

Thomas Pesquet’s spine stretched aboard the ISS

But another phenomenon impacts the skeleton, and more specifically the spine. When it is no longer compressed by gravity, it stretches. This can “stretch” the size of an astronaut, according to a study cited by the daily, up to 3%. A person of 1.70 meters can thus gain a little more than 5 centimeters. As long as you stay weightless for a long time.

With regard to Thomas Pesquet, after 199 days of mission, Le Progrès speaks of “A few centimeters” without further details. Other sources like RTL nevertheless evoke between 4 and 5 centimeters more for the astronaut who is already 1.84 meters tall. This is not the first time that Thomas Pesquet has experienced this phenomenon. During his first mission aboard the ISS in 2017, the astronaut had already gained 4 centimeters.

Read also – What is Thomas Pesquet’s program after his return to Earth?

However, rest assured: in both cases, the astronaut quickly returned to his normal size. Usually, the vertebrae return to their normal position only a few hours after returning to Earth. This does not mean, however, that Thomas Pesquet was ready to chain his landing with a marathon. After such a long stay in space, you have to slowly get used to gravity, which can be quite painful for a few weeks – and even require rehabilitation.


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