And the stars will grant each man new home ..." I defended space exploration from the perspective of a Catholic/"Distributist"/"Back to the Land" economic perspective. And I think the key to this is private individuals rather than the tax payer funding such enterprises. Interestingly, this seems to be the way things are naturally progressing ...
I think the Russians, in practical non-hyper-safety-sensitive Slavic style, were the first to start with a sort of space tourism to help fund their space programme in a faltering economy. Starting in the 2001 they have sent seven fee-paying individuals into space. For $20-35 million USD a number of wealthy adventurers have been able to spend 1-2 weeks aboard the International Space Station (see: http://en.wikipedia.org/wiki/Space_tourism)
A company called "SpaceX" is scheduled to conduct a flyby and docking with its unmanned "Dragon" capsule to the International Space Station on 7 February 2012 (cf. http://news.nationalpost.com/2011/12/09/spacex-will-be-first-private-company-to-embark-on-mission-to-international-space-station/).
More ambitiously, Virgin Galactic (owned by Sir Richard Branson), has been preparing for years to take the first tourists into space. For $200,000 USD, 430 very wealthy people will be able to fly on a suborbital flight into space. There's no firm timeline on when this will actually happen, but in May of 2011 a significant (successful) unmanned test flight was flown of their craft, so it may not be too many more years. They are also not the only ones doing this.
Amazingly (to me), there is also space travel as a form of advertisement as exemplified by the energy drink company Red Bull which plans to have their salaried stuntman Felix Baumgartner ascend to 120,000 feet in a stratospheric balloon and make a freefall
jump that rushes toward Earth at supersonic speed before he parachutes
to the ground. All to get the Red Bull logo a whole pile of exposure (Esquire Magazine has a fascinating article on this mission here: http://www.esquire.com/features/impossible/felix-baumgartner-skydive-0810).
So for now, it is the ultra-rich entertaining themselves, but it is a start. The earliest explorers in the Age of Discovery started out not too much differently -- they certainly relied on very wealthy benefactors to fund privately their projects. Certainly many turned their noses up at Columbus and the Italian investors and the Spanish crown but we all know the results. I believe that in like manner these early excursions into space may appear frivolous but will bear long-term exploratory fruit.