The idea is that older astronauts would take this one-way trip and use their spacecraft as the first habitat. Supply ships and future colonists would then add to the development effort. Not having to send enough fuel and food to get back to Earth would supposedly reduce the projected cost of such a mission by "80%" and would get a human presence on the Red Planet much sooner.
This idea does seem crazy at first, but some good points are made – such as early settlers of the Americas, many of whome never had a solid plan, if any, to return to the home country. The paper also states how communications now, even at the extreme distance that Mars is from Earth, would be better than any postal system was when European settlers ventured farther and farther inland in the Americas.
The article proposes age 60 for these Mars candidates, as this would put the individuals past their pirme reproductive years. Being not a few years away from 60, it's easy for me to say that I would TOTALLY take a one-way trip to Mars – but I'll remain optimistic that by the time I'm 60 we (NASA, commercial industry, international partners) will have figured out how to get people to and from Mars safely with out too much radiation exposure. If not, then maybe Mars could be the ultimate retirement destination for the active 55+ community (no kids allowed)!