The Obama administration's proposed fiscal 2010 NASA budget includes $630 million in additional near-term funding for development of follow-on rockets and spacecraft needed for the agency's post-Columbia moon program, officials said Thursday. But most of the increase is from the administration's economic stimulus package and projections through 2013 show a $3.1 billion reduction in overall funding for the program when compared with 2009 projections.

Unveiling NASA's $18.7 billion fiscal 2010 budget today, acting Administrator Chris Scolese said the Obama administration had ordered an independent review of NASA's plans to replace the space shuttle with a combination of manned and unmanned Ares rockets, Apollo-style Orion capsules and lunar landers needed to establish research stations on the moon by the early 2020s. The new rockets are the central elements of what NASA calls the Constellation program.

"You can expect a new administration coming in wants to understand where we're at and is this the best way to go forward," Scolese said. "That's the purpose of the review, to understand that. Clearly if we're on the wrong path we should change. If you're asking me do I think we're on the wrong path, no, I don't. We need to go off and demonstrate that. The review team needs to look at it and understand what we're doing and offer suggestions on how we could do it better."

The review is expected to be completed by August. In the meantime, NASA will continue work on the Ares 1 rocket and Orion capsules the agency hopes to begin flying in March 2015. But contracts needed for initial development of the unmanned Ares 5 heavy lift booster needed for NASA's planned return to the moon are on hold pending the results of the review.

NASA's $18.7 billion budget request includes $1 billion in Recovery Act money and funds the addition of one shuttle flight to deliver an already-built physics experiment to the International Space Station.

Including next week's launch of the shuttle Atlantis on a fifth and final mission to service the Hubble Space Telescope, NASA plans nine more shuttle fights through Sept. 30, 2010, the end of the fiscal year. If one or two flights slip beyond that target, NASA will need additional funding but the Obama administration has indicated it would support such a request if needed.

"What does this budget represent? I was surprised, in the last month I've seen the president three times," Scolese told reporters Thursday. "And I think that's an indication that NASA is something that this administration really cares about. The fact that we were highlighted in the budget discussions today with the (president's) science advisor is another indication of that. And I think you see it in this first bullet here, a $630 million increase to exploration, a $456 million increase to science and a $264 million increase to aeronautics. Those are significant increases."

Even so, the picture is much less rosy in the out years. Projections through 2013 in the fiscal 2010 budget package feature an asterisk after totals for the Exploration System Missions Directorate responsible for space station operations and development of the Constellation program.

The asterisks mean those numbers may change based on the results of the upcoming manned spaceflight review. But as of this writing, exploration faces $3.1 billion in cuts through 2013.

"We're up this year and next by about $630 million," said Douglas Cooke, associate administrator for the Exploration Systems Mission Directorate at NASA headquarters. "Over that time period, it's down about $3.1 (billion)."

Former NASA Administrator Mike Griffin said in a recent speech the projected funding shortfalls threaten America's leadership in manned space flight.

"In the last five years two presidents and two Congresses have provided the top-level direction necessary to ensure that the root cause of Columbia's loss - the lack of a guiding strategic vision for NASA - never happens again," Griffin said. "But apparently something more is needed. We're not matching the words with the necessary actions at the staff level. How soon we forget.

"Let me be clear. In a democracy, the proper purpose of the OMB (Office of Management and Budget) is not to find a way to create a Potemkin Village at NASA. It is not to create the appearance of having a real space program without having to pay for it. It is not to specify to NASA how much money shall be allocated for human lunar return by 2020. The proper purpose of the OMB is to work with NASA, as a partner in good government, to craft carefully vetted estimates of what is required to achieve national policy goals. The judgment as to whether the stated goals are too costly, or not, is one to be made by the nation's elected leadership, not career civil service staff."

Griffin said "no one can wrest leadership in space from the United States. We're that good. But we can certainly cede it, and that is the path we are on."

Sen. Bill Nelson, D-FL, said he believes Obama understands the value of space exploration and "I believe that's why the president has committed to finishing all nine space shuttle missions, regardless of how long it takes; and, to make full use of the International Space Station."

"This is a step in the right direction," he said. "But down the road the administration's budget does not match what candidate Obama said about the future of our space program. Still, he's assured me these numbers are subject to change, pending a review he has ordered of NASA."

The Constellation program was born in the wake of the 2003 Columbia disaster. The Bush administration decided in January 2004 to finish the international space station and to retire the shuttle in 2010. At the same time, NASA was told to begin development of a replacement system that could ferry astronauts to and from the space station and eventually, on to the moon, a system that would be safer and less expensive to operate than the shuttle. The long-range goal was establishment of Antarctica-type lunar research stations where astronauts can live and work for months at a time.

The Constellation program marked a radical departure from the world of shuttle operations. Instead of one rocket designed to carry astronauts and heavy payloads, two rockets were envisioned: the manned Ares 1, designed to boost Orion crew capsules to low-Earth orbit; and the unmanned Ares 5, a huge heavy lift rocket that would carry a four-person lunar lander into space.

For a moon shot, the Ares 5 would be launched from pad 39A at the Kennedy Space Center, followed a few hours later by launch of the crew in an Orion capsule atop an Ares 1.

After linking up in Earth orbit, the Ares 5 upper stage would propel the Altair lunar lander and astronauts in the attached Orion capsule to the moon. The entire crew then would descend to the lunar surface in the lander and, when its mission was complete, blast off, rendezvous with the orbiting Orion capsule and return to Earth for an ocean splashdown.

The Bush administration did not give NASA much in the way of additional funding to pay for initial Constellation development and the agency has been forced to cut back in other areas to kick start the new program. After station assembly is complete and the shuttle is retired in 2010, NASA plans to divert more than $4 billion a year into Constellation that currently goes into shuttle and station operations.

But given the lack of funding up front, technical problems and changing requirements, NASA will not be ready to begin initial operations with Ares 1 until March 2015. During the five-year gap between the end of shuttle operations and the debut of Ares 1/Orion, NASA will be forced to buy seats on Russian Soyuz spacecraft to ferry U.S. and international astronauts to and from the space station.

Almost from the beginning, critics have complained about the Constellation architecture. Some believe NASA should look into modifying heavy lift Atlas or Delta rockets - evolved expendable launch vehicles, or EELVs - for manned flights. Others believe it makes more sense to eliminate the Ares 1, which requires development of a new five-segment solid-fuel booster, and instead rely on a modified version of the Ares 5, using four-segment boosters, to launch crew and cargo.

The independent review announced Thursday will look into all aspects of the Constellation architecture.

"We were requested to conduct a more detailed study of human spaceflight capabilities," Scolese said. "We want to fully utilize the international space station, that's a decision that needs to be factored into this review, we need to consider the workforce and the transition requirements as we retire the shuttle and move on to the next system and we need to look at what the gap means and how to best utilize the commercial and international capabilities that are out there.

"So the president's science advisor has asked us, and we're forming a review team, a blue ribbon team, that will be headed by Norm Augustine, which we anticipate being done in the next 60 to 90 days. So by August we're prepared to make any budget adjustments that may need to be made."

Cooke said he does not believe a switch to another rocket system would narrow the gap between the end of the shuttle program and the debut of a new system.

"I don't personally see one," he told CBS News. "We have looked at other possibilities in anticipation of questions. I think we've got a plan that gets there as quickly as we know how. If we could come up with one that's better, we'd do it."

He said the biggest single reason he has favored Ares 1 over competing designs is crew safety.

"The biggest difference is in the risk," he said. "We can argue numbers all day long in terms of cost and schedule and that sort of thing and they have different levels of maturity so you're never actually comparing equivalent numbers. But in terms of the risk numbers we've seen and calculated - and I usually look closest at loss of crew numbers - the Ares 1 approach has always been at least two times better than these other approaches comparing EELVs and the Direct 2.0."

That's in part due to the Ares 1 first stage, an extended five-segment shuttle booster. Two four-segment boosters are used for every shuttle flight and in 125 missions to date - 250 booster flights - only one booster has ever failed, the one that doomed Challenger.

"I personally believe the risk is lower for the crew on this vehicle and that to me is the bigger of the discriminators," Cooke said.

While NASA will proceed with work on the Ares 1 program while the external review is underway - an unmanned test flight is planned for later this year - contracts for initial work on the heavy lift Ares 5 have been put on hold.

"I've been inclined to hold off on them because I don't want to presume an answer out of this review," Cooke said. "I think we really need to see where we end up in terms of recommendations there before we start new contracted activity. We're going to continue on our current contracted activities, but to start a new one right now, I'm not sure we've fully developed that thought process. I'm inclined to hold off."

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