Earlier quoted context omitted.
I'd be surprised if there's a single person alive who would volunteer for a suicide mission to a miserable cold dark planet and could travel there for nine months in a tin can through a harsh radiation/muscle atrophy/psychological environment and arrive in any condition to conduct useful scientific work.
Suppose one had a diagnosis of 1 year to live. Why not expend it doing something great?
Like enjoying earthly pleasures? The terminally ill do not make good astronauts.