So what is the legality? AFAIK, euthanasia and assisted suicide are not legal in a lot of jurisdictions. An actual Mars mission may set a precedent, for, uhm, voluntary short-term underwater scientific missions for geriatrics and hospice patience with challenging pain management situations.
For the law, intent usually matters. If you help someone who has the intention to die, then that's assisted suicide. But people can accept any level of danger they please, as long as they intent to survive the ordeal. The actions might be the same, but the intent is different.
