I think what NASA does, with ESA, JAXA, Roscosmos and other space agencies, are a wonderful thing. Thaks to their experiments in space, we know more things, and we must not forget that these experiments also bring prosperity in our everyday life. And even if as you say, there are many other problems in our world, why must we stop our impulse: the searching for a more conscious knowledge.
It's as you say: why do we buy cosmetics eat on fastfoods and junk food despite of spend that money to give to poor!
Unfortunately, the mankind is not perfect and like other living kind, there is something animal in each of us and as I just said this animal part of us is the knowledge, our well-being! Yes we are selfish, and yes we must try to change and certainly we need people like you +Tim Ballard
who make us think, but at the same time we must recognize how we are so selfish! ;-)
(I'm italian, excuse me for english errors....)