What space does to the astronaut’s body

Scott Kelly became famous for spending a total of 340 days on the International Space Station (ISS), the longest time a US astronaut has spent in space. Its mission now provides researchers with fundamental information about what happens to a human body during such a long-term stay in orbit.

Since Kelly has an identical twin, Mark (also an astronaut and soon to become a United States Senator), the researchers had a rare opportunity: While studying what happened to Scott’s body during his year in space, they had the advantage of one with his brother Mark the genetic control subject left on earth. NASA’s twin study was able to provide more information than originally hoped.

Large-scale comparative study

What happens if a person is in a closed capsule in conditions of microgravity and prolonged exposure to radiation? The immune system suffers, the shape of the eyes deteriorates and there is a substantial loss of muscle and bone mass. This was known. But there were also some surprising consequences.

Scott Kelly experienced changes in his gut microbiome, his cognitive abilities slowed, some genes went from active to inactive, and his chromosomes underwent structural changes. “The twin study gave us a first glimpse of a human body’s molecular responses to space missions, but the missing data has now been entered,” says Christopher Mason, Associate Professor of Physiology and Biophysics at Weill Cornell Medical College. “The changes we saw had to be contextualized with parallel experiments. We needed more studies to classify the frequency of changes we saw in other astronauts and organisms that go into space. We also had to find out. If the magnitude of the changes were similar in the shorter missions “.

The twin study was followed by a wide range of research based on it, which re-analyzed existing original data with new techniques and comparisons available with other astronauts. A series of nineteen studies were published in a series of scientific journals in November, including ten preprinted papers awaiting peer review. Researchers such as Mason, one of the principal authors of fourteen articles, examined the physiological, biochemical and genetic changes observed in 56 astronauts who were in space (including Kelly). It is the largest study of its kind ever conducted. The new papers include results from cell profiling and gene sequencing techniques that have only recently become easier to perform. They show that there are “some changes in space travel that constantly occur in humans, mice and other animals,” says Mason. “It appears to be a series of fundamental mammalian adaptations and responses to the rigors of space travel.”