Earth’s magnetosphere protects us from the most harmful cosmic rays that bombard our planet but beyond this natural shield, astronauts are subjected to radiation that is a hundred times more than at sea level.
![](https://scx1.b-cdn.net/csz/news/tmb/2020/growingstemc.jpg)
Source:
https://phys.org/news/2020-03-stem-cells-deep-space-exploration.html