President Bush ordered a sharp change of course for NASA today, directing the agency to complete the space station and retire the shuttle by 2010 and to begin development of a new spacecraft to carry astronauts back to the moon by the middle of the next decade.

The plan calls for NASA to begin launching unmanned probes to the moon within just four years to begin mapping resources and refining knowledge about the harsh lunar environment that will face astronauts making long-duration stays.

Space station research will be re-focused almost exclusively on life sciences as part of what amounts to a crash course on learning how to counteract the harmful physiological effects of weightlessness.

Knowledge gained from station research, development of a new Crew Exploration Vehicle and the infrastructure needed to support long-duration moon missions, the president said, will pave the way for eventual flights to Mars and beyond.

"Today we set a new course for America's space program," Bush said in a speech at NASA Headquarters. "We will give NASA a new focus and vision for future exploration. We will build new ships to carry man forward into the universe, to gain a new foothold on the moon, and to prepare for new journeys to worlds beyond our own."

The president plans to ask Congress to boost NASA's budget by an additional $1 billion over the next five years - an average of $200 million per year - to help kick-start the new initiative. Another $11 billion will come from reallocating money already in NASA's projected budgets by restructuring or eliminating programs and initiatives that aren't consistent with deep space exploration.

The president's plan would increase NASA's budget by 5 percent per year over the next three years and then at a modest 1 percent or less per year for the following two years.

"This increase, along with the refocusing of our space agency, is a solid beginning to meet the challenges and the goals we set today," Bush said. "It's only a beginning. Future funding decisions will be guided by the progress we make in achieving our goals."

House Majority Leader Tom DeLay (R-Texas) said the new focus for NASA "is the next giant leap for mankind."

"The president's vision is exactly what NASA needs: a bold, unifying mission that honors America's forty-year legacy of triumph and sacrifice in human space flight," DeLay said in a statement. "I couldn't be happier with the president's vision, nor prouder of the brave and brilliant people of NASA who will make this dream come true."

But Sen. Bill Nelson (D-Fla.), who flew on the space shuttle in January 1986, said the budget numbers tossed out by Bush today would not come close to funding new vehicles and manned missions to the planets.

"It will be cheap talk unless the president starts putting some real money behind it, immediately," Nelson told CBS News. "And then, everybody will know it's serious."

Rep. Bart Gordon (D-Tenn.) said he welcomed a a new focus on exploration, but said "clearly, we are going to need more information on the proposed timetable for achieving the goals, the costs, how the administration proposes to pay for the initiative, and what the impact will be on the rest of NASA's programs."

He said he was concerned other NASA programs will be "cannibalized" to pay for the new initiatives.

"We now have a half-trillion dollar deficit," he said in a statement. "The president is going to have to make the case for why his proposals should be supported in the face of that deficit. His ambitious space agenda has to be seen to be more than simply a re-election sound bite, or it will be dismissed out of hand by both Congress and the American public.

"Having said all that, I think that the president has kicked off a long overdue discussion on the future of NASA, and I look forward to working with him to craft a productive way forward."

To the enthusiastic audience in a packed auditorium at NASA headquarters, Bush's exploration initiative was music to the ears.

"Today I announce a new plan to explore space and extend a human presence across our solar system," Bush said. "We will begin the effort quickly, using existing programs and personnel. We'll make steady progress, one mission, one voyage, one landing at a time."

The first goal, he said, was to complete assembly of the international space station by 2010.

"We will focus our future research aboard the station on the long-term effects of space travel on human biology," the president said. "Research on board the station and here on Earth will help us better understand and overcome the obstacles that limit exploration. Through these efforts we will develop the skills and techniques necessary to sustain further space exploration.

"To meet this goal, we will return the space shuttle to flight as soon as possible, consistent with safety concerns and the recommendations of the Columbia Accident Investigation Board. The shuttle's chief purpose over the next several years will be to help finish assembly of the International Space Station. In 2010, the space shuttle, after nearly 30 years of duty, will be retired from service."

The second goal of the Bush initiative is to develop a new spacecraft, the Crew Exploration Vehicle, by 2008 with the first manned missions beginning no later than 2014. The new spacecraft will be able to ferry astronauts to and from the space station as well as "beyond our orbit to other worlds. This will be the first spacecraft of its kind since the Apollo command module. "

"Our third goal is to return to the moon by 2020, as the launching point for missions beyond," he said. "Beginning no later than 2008, we will send a series of robotic missions to the lunar surface to research and prepare for future human exploration. Using the Crew Exploration Vehicle, we will undertake extended human missions to the moon as early as 2015, with the goal of living and working there for increasingly extended periods."

Exploring and utilizing the moon makes sense, the president said, because it could "vastly reduce the costs of further space exploration, making possible ever more ambitious missions."

"Lifting heavy spacecraft and fuel out of the Earth's gravity is expensive," Bush said. "Spacecraft assembled and provisioned on the moon could escape its far lower gravity using far less energy, and thus, far less cost. Also, the moon is home to abundant resources.

"Its soil contains raw materials that might be harvested and processed into rocket fuel or breathable air. We can use our time on the moon to develop and test new approaches and technologies and systems that will allow us to function in other, more challenging environments. The moon is a logical step toward further progress and achievement.

Costs aside, some questioned the wisdom of returning to the moon if the real goal is Mars. Louis Friedman, executive director of the Planetary Society, described using the moon as a staging base for flights to Mars as "patently ridiculous." It doesn't make sense, he said in an interview, to first launch humans, their supplies and equipment from Earth to the moon and then to launch other flights from the moon to Mars.

And Friedman dismissed talk about using lunar resources for on-site manufacturing given the relatively short timetables outlined by the president.

"The lunar resources and lunar launch facilities thing just defies credibility," he said. "The other aspects of the moon, being able to set up a base there and practice excursions like you'd do on Mars, maybe that would make some sense. But the moon is very different. ... You could do a lunar base (as practice for Mars), but I've always thought you could do that in Chicago, too."

Even so, he said, "I think the overall redirection of the program is welcome."

"We applaud the administration for providing a vision for where we are going in human space exploration and for providing clear goals to re-energize an enterprise that has been stuck in Earth orbit for more than 30 years," Planetary Society President Wesley Huntress said in a statement.

During a news conference after Bush's speech, NASA Administrator Sean O'Keefe said the president gave the space agency a clear mandate. "We got support for a set of specific objectives that very clearly identifies exploration and discovery as the central objectives of what this agency is all about."

No details about the nature of the proposed Crew Exploration Vehicle are yet available, including how many astronauts it might seat, how it will fly through an atmosphere or even what sort of launcher might be needed to boost it into orbit. It could be a modular system, adaptable to different sorts of missions, or a more monolithic design. O'Keefe stressed that nothing has been ruled out and that multiple systems are on the table.

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