"Over the next 10 years, NASA is scheduled to devote $99 billion to the nation's human spaceflight program. In recognition of the magnitude of these planned expenditures, coupled with questions about the status of the current human spaceflight program, the White House Office of Science and Technology Policy, as part of the due diligence of a new administration, called for an independent review of the present and planned effort. Two conditions framed this request: all ongoing human spaceflight work by NASA and its contractors was to continue uninterrupted during the review process; and the review team's findings were to be available 90 days from the Committee's formal establishment and a formal report be published thereafter, in recognition of the demands of the federal budget preparation cycle. The Committee established to conduct the review comprised 10 members with diverse professional backgrounds, including scientists, engineers, astronauts, educators, executives of established and new aerospace firms, former presidential appointees, and a retired Air Force General. The Committee was charged with conducting an independent review of the current program of record and providing alternatives to that program (as opposed to making a specific recommendation) that would ensure that 'the nation is pursuing the best trajectory for the future of human spaceflight--one that is safe, innovative, affordable and sustainable.' Initially, the directive to the Committee was that it conduct its inquiry with the assumption that operation of the Space Shuttle would terminate in 2010 and that the 10-year funding profile in the FY 2010 President's budget would not be exceeded. In subsequent discussions between the Committee chairman and members of the White House staff, it was agreed that at least two program options would be presented that comply with the above constraints; however, if those options failed to fully satisfy the stated study objectives, additional options could be identified by the Committee. No other bounds were placed on the Committee's work."
White House: http://www.whitehouse.gov/s