How do space agencies keep astronauts safe from radiation?

Space radiation comes from solar particle events and from galactic cosmic rays, both of which can be dangerous outside low Earth orbit. Spacecraft use shielding materials, and habitats are designed with protected areas where astronauts can shelter during solar storms. Mission planners also try to limit time spent outside Earth’s magnetic field and monitor space weather continuously. NASA and other agencies track doses carefully because radiation risk is one of the main challenges for long-duration missions to the Moon and Mars.