[ShadowAce]

Yeah. Sure. What you said.

[GingisK]

Some NASA documentation indicates that astronauts can survive a year between here and Mars without harmful affects given the current state of the art. Other documents indicate that colonists on Mars could handle 60 years in underground shelters with limited exposure on the surface.

It is all about shielding and exposure times. The shielding is based upon the mass of material that separates the person from exposure to space. The atmosphere provides about 10 tons per square meter of shielding for "earth normal" exposure. The magnetic field is also very helpful.