I was recently asked to answer a rather interesting question on Quora. Here is my answer:
Q: How would you prepare mentally if you accepted a one way mission to Mars?
A: To be perfectly honest, the chances of such a mission occurring are extremely slim at best. No space agency will approve a suicide mission, where a loss of life will occur. Also individuals who would agree to such a mission will most probably not fit the desired psychological profile. A person who would emotionally desire a one-way journey to Mars, by sacrificing his life, is exactly the opposite of the calm, emotionally unaffected and modest astronaut (all the Apollo astronauts fit perfectly here, especially Neil Armstrong).
And if by a one way mission you imply colonization, where the risks are still high, but survival is anticipated, this turns into a completely different question. In my opinion psychological training does not represent a large part of astronaut training, as compared to physical and technical aspects of preparation. Most astronauts are in their thirties, where they have already developed their characters and showed their psychological endurance and vitality. Of course, a possible mission to Mars will most likely have more than one crew member (the ideal number is speculated to be between 4 and 6), hence team building is an essential part of training (there is also always a backup team, of course). Astronauts are isolated on many occasions during training (for example when they are dropped into a remote from civilization area, where their survival skills and psychological qualities are trained, and also later assessed by specialists).
To sum up – if you are offered such a mission, you are most probably already prepared. For more information on the topic of spaceflight psychology I recommend the following book: Space Psychology and Psychiatry (Space Technology Library) by Nick Kanas and Dietrich Manzey.
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