Long stay in space negatively affects human health. For example, American astronaut Scott Kelly, who was aboard the ISS for a whole year, changed the end sections of chromosomes - telomeres and intestinal microflora. His bones partially lost their density, as a result of which his legs ached three months after his return.
In outer space, conditions are absolutely incompatible with the life of terrestrial creatures due to hard ultraviolet radiation, vacuum, sudden changes in temperature and microgravity. However, such an obvious fact was denied by the bacteria Deinococcus radiodurans, which managed to survive after a year on a special platform outside the ISS.
Five years ago, an international team was formed as part of the Tanpopo mission to experiment with incredibly survivable bacteria outside the Japanese Kibo module.
In the beginning, microorganisms dehydrated on Earth were delivered to the ISS and placed on a special platform completely exposed to the influence of the space environment. True, the cells were behind a glass window that blocks ultraviolet radiation with a wavelength of less than 190 nanometers.
After such an extreme year-long experiment, the bacteria were returned to Earth, where the water level in them was completely restored and compared with control samples. The survival rate of bacteria from the ISS turned out to be significantly lower and the surviving bacteria were slightly different from their terrestrial relatives.
Another small detail discovered by scientists and which they cannot yet explain is that bacteria from space have appeared tiny bumps on the surface. In addition, they have increased the number of certain proteins and mRNA molecules.
The results of these studies will help to understand the possibility of beneficial bacteria to survive in the extraterrestrial environment and accompany humans on interplanetary missions.