Russia still custom-builds the Soyuz return seats for ISS crew members using plaster casts taken weeks before launch, because astronauts grow as much as five centimetres taller during a long-duration stay and a seat moulded to their Earth-shaped spine would no longer fit the body that comes home

Scott Kelly came back from the International Space Station in March 2016 measurably taller than the brother he had left behind on Earth. After 340 days in orbit, the NASA astronaut had grown in spinal length, a change his identical twin Mark — a former astronaut himself, staying Earth-side as a genetic control — had