@mathowie ah, my favorite hill to die upon: assuming healthy colonists survive the trip and land on Mars, the first three or so generations of colonists are likely to have shortened lifespans and die horribly thanks to the lack of a magnetosphere protecting them from radiation; or live crouched in lead bunkers under the surface, which hardly seems ideal.
Mars should be only peopled by landings of ever-smarter robots until we figure out how to change the human body to survive space travel through engineering or cybernetics.