I'm all for increasing NASA's funding. Not so long ago, its budget was $20 billion annually, whereas Americans blew about $ 80 billion on tobacco alone.
Particularly in the long run, NASA's achievements are far more than academic. Increased investment in space need not compete with saving the environment; it may actually be the key to it. Years ago, Princeton professor G. K. O'Neal proposed relocating industries to space. The moon for example, has no ecosphere to mess up, and besides mineral wealth its lower gravity makes easier to get things done. In addition abundant lunar (and mercurian) He-3 may someday enable us to produce energy elsewhere and beam what we need here.
Regarding the search for alien life, I do however, have a slight criticism of NASA priorities. IMO they've invested to much on Mars too little on the search for exoplanets. For all its mystique, Mars is hopelessly small--only about a tenth of terrestrial mass, and almost airless. If missions like Kepler had been emphasized by now they probably would've found a truly Earthlike planet out there (kepler 452b is probably more venusian than earthlike).