I’m just wondering about the ethical issues and possible legal questions.
You wouldn’t let a person commit suicide. Why would you let someone get stranded on Mars when they can’t honestly say for sure they won’t have a nervous breakdown (or worse) when they get there? I mean nobody’s had the experience of being stranded on another planet (OK, nobody we know of) so how can somebody really give an honest answer to how they’d cope?
If they do have a severe mental breakdown after being stranded on Mars would public opinion force a country to send a rescue mission? If that happened who would pay for it? Would there be legal prosecution as a result of it and if so who would be liable?
We are already in a situation where, for example, men and women risk their own lives to rescue adventurers be in a wild part of a forest or in mountainous seas off some coast. If a country did feel compelled to send a rescue mission to Mars then I presume they too would be asking their people to risk their own lives in the attempt.