Answer: Could change/save the world as we know it.
Short-sighted discreditors of space exploration often question what good it is to have a man on the moon. What good can come of sending probes to Mars for so many millions of dollars? Leaving aside mankind’s natural impulse to learn and understand everything around us (not to mention how well it has served us), practical reasons for exploring something as barren as our moon do run thin to the average citizen. While I do so value the science that happens at such remote locations, it is the getting there that challenges us to push the boundaries of known science. Coming up with a better and safer means of space travel can wind up producing something like this; a potentially abundant green source of energy that could transform the world and be the answer to many of the problems facing the us today.
What is often hard to explain to people who negate the need for space exploration are the side benefits of such programs for the whole world. Just like wars, performing something as technically challenging as space exploration results in pushing the boundaries of science in directions it might not have otherwise gone. When Sputnik was launched, most believed that space would go the way of a militarized zone and become a new battleground for superiority. Instead, all these years later we enjoy a vast communication network that has helped topple entire governments without a single bullet being fired. If it is a choice, I would choose space exploration over another world war to press mankind further along the path of progress any day.
So to those who think the best that going to the moon has produced is velcro — consider the possibility that by NASA may be on the way to providing the world with abundant clean energy as the result of trying to find a cheaper safer way to the stars. Not a bad fringe benefit.