It's because of this I like the concept for a one-way mission crewed by volunteer elderly astronauts. Why worry about developing a cancer 20 years down the line due to cumulative space radiation exposure, if your remaining life expectancy is lower than that, and you fully expect dying of old age in Mars anyway: https://web.archive.org/web/20101023054414/http://journalofc...

With the current worldwide ageing demographics, it would have the added benefit of providing an awesome feat to inspire seniors across the world to not go gentle into that good night, showing old age should burn and rave at close of day.