It's simple, really: I'm not in it for the science, I'm in it for getting our eggs out of this fragile and rapidly deteriorating basket they're in. The more decentralized humanity becomes, the better its chances for continuing to be around. I say, let robots do the science if you want, but still send people up there and get experienced at it so that others can follow and found a multitude of branches of civilization. If we say, "Robots are cheaper," and never send people up, then eventually those probes are all that will remain.
And for my progressive comrades who may argue that the money is better spent down here, I would remind them that:
- NASA gets a truly miniscule fraction of the budget and far less than social programs.
- The money doesn't disappear into orbit, it pays the salaries to thousands of workers and gets taxed and redistributed.
- The long-term survival of humanity is just as noble a goal as the short-term survival of individuals.
UPDATE: So it won't happen today, but still.