The news on TV today has been all about the shuttle launch (now delayed), so the old Is-it-worth-it-to-go-into-space story that gets recycled every space launch is ubiquitous again.
Here's the problem -- of course it is worth it, but we don't know why. Let me explain:
In the late 15th century, Columbus set sail in an attempt to find a shorter trade route to the Indies, and bumped into the New World instead. He was looking for spices, and instead found a continent. Even when he arrived at the New World, it never occurred to him that he had found new land. He had found something of value beyond his comprehension. Imagination failed.
Conquistadors came to the New World seeking gold, particularly the fabled El Dorado. The marched all up and down the Americas looking for the fabled gold, but it never occurred to them that they were seeking a lesser treasure. Even at that time, the greatest wealth was not in currency, but in land. They walked and rode over a fantastic treasure -- two continents worth of land -- yet they were so focused on the gold that they could not perceive the great treasure beneath their feet. Even if they had found El Dorado, of what value could a single city of gold be against two continents of land with new, undiscovered resources like rubber and chocolate. Imagination failed.
Arctic explorers travelled through and died in a land apparently devoid of value. The native peoples who dwelt closest lived a Stone Age existence -- not because they were fools, but because in such a hard land survival itself was at this primal level. There was no tillable land, and not even a legendary El Dorado to seek. Beyond the challenge, little motivation existed. Yet, they did it, and below them were vast oil reserves of which they did not even dream. Imagination failed.
Of course, these are merely explorations of physical space, ignoring the more valuable explorations of the mind. When Newton "discovered" gravity, of what value was it? I suspect more then one person said to him, "Pfft. Stuff falls down. I coulda told you that." Da Vinci explored areas through art that were centuries ahead of use. Akhenaten's ideas suggesting monotheism flew in the face of three millennia of Egyptian thought, and met with a backlash upon his death, with the attempted destruction of record of him -- yet monotheism eventually won out.
So, can I articulate a justification for risking blood and treasure to venture out into a cold, dark void? No, I cannot. Imagination fails.