Radiation shielding is either heavy, or difficult. Heavy is too expensive, and the quietly cold calculus of many seems to have been, “well these early explorers

Radiation shielding is either heavy, or difficult. Heavy is too expensive, and the quietly cold calculus of many seems to have been, “well these early explorers won’t live as long as us.” This however injects the possibility of mission failure, not just a bad end for early Mars colonists on slow boats from Earth.