How do we cut the cost of sending astronauts to Mars? Lawrence Krauss dares to make this suggestion:

The most challenging impediment to human travel to Mars does not seem to involve the complicated launching, propulsion, guidance or landing technologies but something far more mundane: the radiation emanating from the Sun’s cosmic rays. The shielding necessary to ensure the astronauts do not get a lethal dose of solar radiation on a round trip to Mars may very well make the spacecraft so heavy that the amount of fuel needed becomes prohibitive. There is, however, a way to surmount this problem while reducing the cost and technical requirements, but it demands that we ask this vexing question: Why are we so interested in bringing the Mars astronauts home again?

Krauss suggests that we could get many volunteers for a one-way mission, but that we should choose older astronauts, who have already lived most of their lives. Many people would be aghast to read this. But consider that it's a matter of degree, in that we do tolerate consistently high death rates for some jobs, such as combat soldiers and, of all things, pizza delivery:

On-the-job accidents and homicides claimed the lives of 5,524 Americans last year . . . Of that 5,524, only 104 were timber-cutters, but those fatalities represent a death rate nearly 30 times that of a typical workplace. Loggers died at a rate of 117.8 per 100,000 workers, the BLS said, with most of them killed by falling trees. Fishing was the second most dangerous occupation, with 71.1 deaths for every 100,000 workers, followed by pilots and navigators, 69.8, structural metal workers, 58.2, and, perhaps surprisingly, drivers-sales workers, which include pizza delivery drivers at 37.9.