I haven't posted here very much, but space exploration is a topic I feel strongly about, so I thought I'd jump in.
First, I have to say that I have a number of significant disagreements with the way NASA spends its money and what priorities it chooses. I think manned space flight is highly overrated, or at least the sort of manned missions that NASA focuses on. This has been true ever since the Apollo missions, when the purpose was not to establish any sort of foothold in space, but simply to beat the Russians to the moon. Similarly, the Space Shuttle program has been an expensive boondoggle that has produced very little of any permanent value. The original vision was for a cheap, safe, reusable vessel that could take off weekly or daily, shuttling people and equipment up to orbit. Instead, we get a hugely expensive and apparently quite dangerous vehicle that has retarded the development of genuinely useful spaceplanes.
That said, I think NASA also does a lot of good. Planetary exploration missions like Mariner and Voyager and Galileo have produced a lot of excellent scientific data for a relatively low cost. The Hubble telescope has done as much for cosmology in ten years as was done in decades before its launch. The International Space Station may be hugely expensive, relatively useless, and decades behind schedule, but at least it represents some attempt at a human presence in space.
I also don't understand the attitude that we should not fund pure research when there are practical problems to be solved. I don't think the two are mutually exclusive, and pure research often leads to completely unexpected ways of solving problems. The view that only the practical is important is, of course, a long-standing American view with a proud history, but I think anti-intellectualism is an ultimately unproductive way of thinking. Also, while it is obviously important to address immediate needs and problems, it also seems wise to me to invest in the future.
Also, the total NASA budget for 2003 is $15 billion dollars. A lot of money to you and me (though not to Bill Gates) but only about 2% of the total discretionary spending of $755 billion, and about .7% of the total outlays of $2.1 TRILLION. I am all for reallocating our spending priorities, but NASA is far from the first place I would look for such things. Consider that we spend more than ten times the NASA budget just on interest on the national debt. But since Mars is far away and pure research rarely yields immediate practical results, it's an easy, though in my opinion unjustified target for outrage.