How do you define "expensive" when the borders of true exploration and the outcome are unknown?
For example, a big national job program which intends nothing more than to do a big media show of casting a few more footprints on the surface of the Moon under the fig-leaf "science". 50 billion USD for designing and building a system that carries 50% less payload into LEO than the Shuttle and causes higher operating costs just for the sake of pushing G.W. Bush's post-STS-107 consolation agenda through. Yes, it has been said before many times, but you asked 
The cancellation of Constellation doesn't have to be excused. It was the right decision at the proper time, analysed by people who really have a clue (and foreseen for years by many people inside and outside the business who also have a clue).
Exploration costs money indeed. But there is an "at any price" mentality which, again, failed on Constellation this time. The correct sentence should be that NASA's manned space exploration is expensive due to the fact that NASA is a very big bureaucracy and a big national job machine. It can be done by less costs and more innovation but NASA needs to be restructured. NASA is not doing fine just because everything NASA does is so amazing. Less than ever by the excuse that exploration just is expensive.
A potential manned use of Orion already is part of the Commercial Crew Initiative by the way. And it won't be the end of exploration and NASA
Moonwalker, I don't believe you know so little about the Back to the Moon phase of Constellation. I'll assume that you described it as an expensive show just to support your claims. For the benefit of everybody here, I'll make a point explaining that without actually building a base on the moon and continuously living there for 10-20 years, you will never be ready for sending a human expedition to Mars. The Moon is an essential stepping stone to a "beyond" manned mission, and not an expensive photo opportunity.
The only fault of Constellation IMHO was that it was too ambitious in the sense that it wanted to cover everything in one go: transportation to the ISS, Moon AND beyond.
If Constellation would have been a Moonbase Program only, it would have had more chances to survive. The current signs are that this is exactly what is happening: Constellation will be a Moon program only and the US will be back on the Moon around 2020. The main part of the Constellation program will be building a Moon habitat where human will explore the limits of life-support and self-support, living off the "land" and learning what it means to maintain an active, long-term outpost far from Earth. NASA will explore new types of planetary transportation, building materials and building methods, the life-support needs for a sustainable human colony, and understand the supply logistics involved in such an operation. During this critical and unavoidable stage, it will also be developing the necessary platform and propulsion technologies for reaching beyond. Constellation is being resuscitated, but with a different set of goals.
Just as before, NASA will rely on thousands of contractors for supplying critical components, but "routine" LEO transportation will most likely be passed to private companies.
Budget was never the main issue - currently NASA has more budget than before - it was mainly a political issue. Budget was the convenient excuse, riding the real-estate and credit crisis and the unpopularity of the big corporation bailouts designed to save the jobs of thousands of car industry workers which were part of the current Administration constituency. AIG - the biggest non-car-industry bailout receiver has already begun the payback. Not so with the car industry. NASA was yet another sacrificial lamb on the altar of political correctness and populist (yet misguided) decisions. The NASA mandate itself was hit by clueless and radical politicians who tried to rape its science and exploration mandate, with irrelevant racial, ethnical and political manifests designed to serve its ulterior political motives. Everything changed however with the mid-term elections, when the current Administration got a painful reminder that hungry and jobless voters are not a good idea, and that "yes we can" has to be backed by The People and not dictated arrogantly by a bolshevik-style governing, where the government "knows better what's good for the masses". Its reckless political spending is now being scrutinized and it seems that many if its political decisions devised to changing the political fabric of the US will be stopped and hopefully reversed.
I only hope it's not too late, as NASA has already suffered incalculable damage by the on-going layoffs, losing thousands of man-years of knowledge and experience.
/Admin
