Suicide ideation and someone willing to take massive risks for something awesome are very different things
> The trip is far more awesome than anything I have planned for the rest of my life.
If you would give your live for a single awsome trip (and you would still have multiple years to live), then you are likely suicidal.
Even if it is rational because your live sucks so hard, I would still have to classify you as suicidal.
I'm sure the other astronauts are really looking forward to fly with a person showing signs of tolerating massive risks.