The Ethics of Space Travel

I wondered today, as I read the recent news on the Indian Mars Mission, whether there are ethical problems that we, as humans, need to resolve regarding our space travel. The principal question in my mind was this: should we be exploring space at all? I hope this doesn't come off as sounding disinterested or critical of space programs - I've been fascinated with space and space travel my entire life, and would still trade just about anything for the opportunity to get up there. However, I wonder if this exploration is justified when we consider the human condition here on earth. I am not well-versed in current world issues, but I know for a fact that there is great need in almost any part of the world for better living conditions, more food, better healthcare, and access to many other basic necessities. It seems to be an almost sardonic display of disregard for us to spend billions upon billions to send one or two privileged individuals (or bits of metal and glass, as the case may be) into space, while leaving millions of starving people behind. I recognize the need for human ambition and inspiration for future generations, but is it worth the cost?