Over the past 50 years, we've seen men first orbit the globe and then walk on the moon. We were gripped b the fictional journeys of the Starship Enterprise, which explored the galaxy, encountering new life and new civilizations. Popcorn in hand, we watched Matt Damon struggle to survive in "The Martian."
We have dreamed of a time when humans can travel through space as readily as when early mariners unfurled their sails and headed west in search of new lands. But we might not have stopped and asked an important question.
Should we be doing that?