I too hate to see a mission fail (such as screwing up English/Metric units and burning up a spacecraft in the Martian atmosphere - a true waste) - but I'm not sure "exploration" in itself is a "dead-end."
This is not a new subject as there have always been folks who have said we should "boot" the space program and spend money on "local" societal issues/problems - e.g. job creation, welfare, the homeless, hunger, etc.
But, I guess there are 2 points I'd like to make here. (1) Humans, in general, are curious creatures - we simply want to "know stuff". Whether it be space exploration or things more terrestrial- and (2) There are benefits that aren't always apparent at first that do wind up giving us back <font color=blue>"a real value"</font color=blue>.
(1) Curiosity: What about Einstein & others who "explored" the power of the atom? What about Archaeologists who "explore" the fossil record? What about those "explored" new lands (e.g. North America, etc)? Regardless of the motivation (e.g. money, power, prestige) or funding (private or governmental) I'd venture to say that curiosity was also a driving force to these individuals actions. I.E. Knowledge is a good thing. Does that mean any crazy "exploration" activity should be pursued? Heck no! Should we go broke doing it? Heck no! But I believe that we should not only "focus" on things that bring "real value" - I would rather learn and expand my education/understanding (that's why I paid my way through school after all).
(2) Paybacks: There are always spinoffs of exploration that give "real value." No, not everything, and no, not always right away, but due to the nature of exploration missions (often hard to do, complex, distant activities), they in themselves force us to solve problems that we never would have tried to solve. Then, somewhere down the road, we find where that solution can offer "real value" to something "closer to home". For example, the Apollo missions led directly to CT & MRI scans and kidney dialysis to the medical community. Even though they were never intended to lead to these capabilities, millions upon millions of patients have benefitted due to this "explorative technology". In my book, I think that fits the term "real value".
Look, I'm not trying to be snide or a "smarty pants" about any of this. And I agree, the government spends WAY too much money on bogus things, (and there are LOTS of govt. programs I'd like to see 'cut'!). But, that being said, I believe the view to <font color=blue>"stop exploration for explorations sake" </font color=blue> is a bad idea.
PS: This is where you can look up what the US space program (including missions to Mars) has contributed regarding the "real value" world.
<A target="_blank" HREF=http://www.sti.nasa.gov/tto/>http://www.sti.nasa.gov/tto/</A>