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?
«This study shows that while space radiation imposes strict limitations on how heavy the spacecraft can be and the time of launch, and it presents technological difficulties for human missions to Mars, such a mission is viable,» said Shprits, who also is head of space physics and space weather at GFZ Research Centre for Geosciences in Potsdam, Germany. The researchers recommend a mission not longer than four years because a longer journey would expose astronauts to a dangerously high amount of radiation during the round trip — even assuming they went when it was relatively safer than at other times. They also report that the main danger to such a flight would be particles from outside of our solar system. Shprits and colleagues from UCLA, MIT, Moscow’s Skolkovo Institute of Science and Technology and GFZ Potsdam combined geophysical models of particle radiation for a solar cycle with models for how radiation would affect both human passengers — including its varying effects on different bodily organs — and a spacecraft.
The modeling determined that having a spacecraft’s shell built out of a relatively thick material could help protect astronauts from radiation, but that if the shielding is too thick, it could actually increase the amount of secondary radiation to which they are exposed. Galactic cosmic ray activity is lowest within the six to 12 months after the peak of solar activity, while solar energetic particles’ intensity is greatest during solar maximum, Shprits said.