Other aspects of the February plan, though, remain unchanged, including a reliance on commercial operators to transport astronauts to low-Earth orbit. As if to emphasize this, prior to his speech, Obama visited the Cape Canaveral launch pad used by SpaceX, speaking with company founder Elon Musk by the company's Falcon 9 launch vehicle, which is slated for its first launch next month.

If the speech was intended to win over skeptics and opponents of the agency's new direction, it was not an immediate success. Many members of Congress who spoke out against the budget proposal in February were not mollified by the president's words. "The president's announcement, unfortunately, still will do nothing to ensure America's superiority in human space exploration or to decrease our reliance on Russia in the interim," said Rep. Ralph Hall (R-Texas), the ranking member of the House Science and Technology Committee.

Others, though, softened their views. "The changes that the president has outlined to his NASA proposal are steps in the right direction and a sign that he is listening to my concerns, but there is still room for improvement," said Rep. Suzanne Kosmas (D-Florida), whose district includes Kennedy Space Center. Kosmas was pleased by a $40 million plan announced in the speech to support the region's economy, which is facing the loss of thousands of jobs when the shuttle is retired later this year.

The first test of the president's updated vision for NASA will come this Thursday, when a subcommittee of the Senate Appropriations Committee holds a hearing on the budget proposal. Sen. Barbara Mikulski (D-Maryland), chair of the subcommittee, has said little publicly about the agency's new direction since February, but she has expressed concern about a lack of specific destinations, something last week's speech addressed. However, the committee's top Republican, Sen. Richard Shelby of Alabama, has been a harsh critic, and said after the speech the plan "continues the destruction of 40 years of U.S. space supremacy by pinning our hopes for success on unproven commercial companies."

The president, though, hopes the plan is seen as an enhancement of such supremacy, despite the disruption it causes in the near term. "That is exactly why it's so essential that we pursue a new course and that we revitalize NASA and its mission--not just with dollars, but with clear aims and a larger purpose," Obama said.