Astronauts spend 6+ months at a time on the space station, without protection from the Earth's atmosphere. I'm told the magnetosphere is only helpful against so

Astronauts spend 6+ months at a time on the space station, without protection from the Earth's atmosphere. I'm told the magnetosphere is only helpful against solar flares, not cosmic rays, and you can shield against solar flares with a storm shelter on the vehicle. Also, you can do a one way trip in 6 months if you're willing to spend a bit more fuel. So 12 months total in space. A trip to Mars today, given our present state of knowledge, would be safer than Apollo was given our knowledge at the time.