re: Terminal illness. - A good reason IF the one way plan would be it.
People that don't have long to live do tend to make everyday and every minute count.
I do hope that they plan for a round trip that involves three people as with Apollo. I know I would value such companionships on such a trip. It would also ensure scientific success should one perish. I'm sure every astronaut in the corp is well aware of such risks today.
Part, a LARGE part of such a trip would be to "safely return them to the Earth". It would make it truly successful, imho.
