The radiation hazards of deep space fight by humans is not publicized that much by NASA and space advocates. It is a real danger and will require mitigation measures before we can commit to sending people for extended periods beyond our magnetosphere. There are aready studies for solar flare alert instruments for when we return to the Moon. The instruments will alert astronauts in enough time for them to find shelter to avoid fatal exposure from the intense radiation from massive coronal mass ejections (CME) from the Sun.

For Mars-bound astronauts, perhaps they will store their water in a jacket around the crew compartment in order to provide protection. Or they could engineer a smaller "safe" compartment inside a large water tank.