The truth that dare not speak its name is that personed space travel can not be justified what so ever.
The shuttle and the international space station is a colossal waste of money. Putting a person into space is too expensive.
Better results can be obtained from smaller cheaper robots, with out the cost in human life.
It is time that personed space travel was consigned to the dustbin of history as an expensive folly that was the last relic of the cold war
Besides why do we need to know about the outer planets or Mars, when the money could be better spent on more deserving causes.