Will It Be Safe For Humans To Fly To Mars?

Sending human travelers to Mars would require scientists and engineers to overcome a range of technological and safety obstacles. One of them is the grave risk posed by particle radiation from the sun, distant stars, and galaxies.

Answering two key questions would go a long way toward overcoming that hurdle: Would particle radiation pose too grave a threat to human life throughout a round trip to the red planet? And, could the very timing of a mission to Mars help shield astronauts and the spacecraft from the radiation?