How Safe is Travel to Mars? RedOrbit

As NASA lays plans for travel to the moon and Mars, the agency is exploring propulsion systems, crew modules, and habitat structures. It has looked at the psychology of being cooped up with fellow astronauts for a years-long Mars mission, and studied how to maintain bone structure and muscle strength in microgravity.
But a new study should force renewed attention on one of the most intractable dangers of space travel: radiation. The review, published Sept. 29 in Mars, the International Journal of Mars Science and Exploration, identified major radiation hazards that must be solved before the safe completion of a human Mars mission.