Today may mark the imminent end of US ambitions to lead space exploration. The "Vision for Space Exploration" (VSE) that former president Bush initiatied (however, neglecting to provide appropriate funding) may be axed.
If this proposal goes through, it may limit the US human space exploration to low Earth orbit for a long time. Not a very attractive option, especially in view of the more than $9 bn that already have been invested into the development of the Ares I and Ares V heavy launchers and the Altair moon landing craft, which may now well be eliminated from the Constellation project.
Here is an interview with spaceflightnow's Miles O'Brien with Lockheed Martin's John Karas on the future of the VSE. LockMart is prime contractor for the Crew Exploration Vehicle Orion that, if also axed, will not leave much of Constellation, nor of American manned spaceflight leadership.
spaceflightnow.com web site
"This Week in Space" on youtube with this and other interviews und information
Article "White House Confirms Course Change for NASA" on space.com