I look back to the history I know coming from a western perspective. Columbus faced immense danger when he set sail for India across the Atlantic. Edmund Hillary faced a strong possibility of death for himself and his entire team when they scaled Mt. Everest. What of Magellan when he sailed around the world, or Franklin as he lead an expedition into the Arctic. Not to mention the people who explored the Amazon, or the Nile, or the Antarctic, or even those who risked everything on those first trips to India around Africa.
All these people faced enormous risks to achieve their goals while many others succumbed to those same risks.
As alluded to above, this short list of risk takers come from my western perspective. I can guarantee that people familiar with cultures I know too little about can produce a similar list.
I will go so far as to state that there are many lay-persons who follow space exploration who know more about the risks astronauts will face on a Mars journey than most of those early explorers did regarding their own travels.
Relatively speaking, and in my opinion, a manned trip to Mars isn’t any more dangerous than any previous voyage of discovery we now celebrate as heroic.
Someone is sure to question the cost. What did it cost ancient mariners to outfit a ship? How much did it cost Marco Polo to reach China? How much did Edmond Hillary pay to scale Everest? As for NASA itself, I believe I adequately addressed that question here.