In his first appearance before Congress since the public release of a budget request that quickly stirred controversy inside and outside his agency, NASA Administrator Mike Griffin told lawmakers he had no choice but to dramatically slow the forecasted growth rate for science spending and cut aeronautics in order to free up money needed for the space shuttle and international space station programs.

NASA is seeking a total of $16.792 billion in its 2007 budget. While that represents an increase of about 1 percent over the previous year’s budget, many science programs are getting less of an increase than NASA had forecast a year ago.

While NASA is seeking a 30-percent increase for its Exploration Systems programs for 2007, Griffin said the agency’s five-year budget forecast actually takes $1.5 billion away from the future exploration efforts to help cover a shortage in the space shuttle and space station budgets. NASA has estimated that shortages in the shuttle and station accounts will total $2.3 billion though the end of the decade.

At present, NASA plans to fly 16 shuttle missions to the international space station before retiring the shuttle fleet in late 2010. Agency officials have said those 16 missions will be sufficient to honor U.S. commitments to Europe, Japan and other nations that are depending on NASA to launch their modules and hardware to the station.

At the same time, NASA is beginning development of the spacecraft and rockets that will replace the shuttle.

“We are trying to retire an old system and finish up a legacy program where we have international commitments and at the same time we are trying to bring about a new capability — a new system in such a way that we don’t lose all the experience base and all the industrial base that has been created to do these sorts of things,” Griffin said. “It is a difficult and delicate juggling act and it does create some broken china.”

Some of that “broken china” includes delaying several major new science missions, grounding most aeronautics flight demonstration projects and cutting basic and applied research spending in every part of NASA’s portfolio.

Griffin was unapologetic about having to go back on a pledge he made last year to “not cut one thin dime” from science to bolster the agency’s human spaceflight programs.

“I believe that the human spaceflight portion of our portfolio is the one in the most need of nurturing and care right now and that is what I am trying to do,” Griffin said.

House Science Committee Chairman Sherwood Boehlert (R-N.Y.) said he understood NASA’s predicament but was undecided about what to make of a budget request he deemed troubling.

“I am extremely uneasy about this budget, and I am in a quandary at this point about what to do about it,” Boehlert told Griffin. “This budget is bad for space science, worse for Earth science, perhaps worse still for aeronautics. It basically cuts or de-emphasizes every forward-looking, truly futuristic program of the agency to fund operational and development programs to enable us to do what we are already doing or have done before.”

Boehlert said that he supports the Vision for Space Exploration but does not “see any reason to accelerate it beyond the president’s original plans,” which called for fielding the Crew Exploration Vehicle (CEV) by 2014 and landing astronauts on the Moon by 2020.

Boehlert also said he would be willing to support giving NASA more money than the White House requested as long as the money goes to the unmanned side of the program and did not come from other science agencies. “But money is not exactly growing on trees around here so what to do is not clear,” he said.

Rep. Bart Gordon (Tenn.), the committee’s ranking Democrat, said he too was undecided about what should be done about NASA’s budget, but raised the possibility of delaying the CEV beyond 2014 and postponing the first lunar landing beyond 2020 if that would free up money for science and aeronautics.

“Why is 2018 a magic date instead of 2020 or later?” Gordon asked.

Before explaining that NASA already has had to adjust its expectations about closing the gap between shuttle’s retirement and CEV availability, Griffin first took issue with Gordon’s suggestion that NASA was “cannibalizing” science and aeronautics to pay for the shuttle and station programs.

“Why was it not considered cannibalizing when the science budget within NASA grew from 24 percent to 32 percent of the agency’s top line? When that was happening no one complained and yet human spaceflight was suffering,” Griffin said. “But our constituency groups didn’t find a problem with that.”

Gordon, who like other committee members has heard plenty in recent weeks from people unhappy with NASA’s budget request, had a ready reply for Griffin: “That may tell you something,” Gordon said. “No one complained and they are complaining now.”

“Touche,” replied Griffin. “But I am complaining. The human spaceflight portion of our portfolio, as fully revealed in the wake of the loss of Columbia, has been damaged and has been damaged for three decades.”

Griffin then returned to a discussion of what NASA’s 2007 request means for CEV and the rest of the exploration program .

“Before we started slowing down any science missions, we had already slowed down the development of the CEV, that’s the shuttle replacement vehicle, to the 2013-2014 time frame,” Griffin said. “That’s where we are sitting. We already have a lunar return program which, sitting here today, will return humans to the Moon by 2018 without allowing for any possible program slips in the future. To slip out beyond that I think is to court lack of credibility. We took our slips up front.”

Although 2014 was the original target for fielding the CEV, Griffin made clear before taking his oath of office last April that he intended to accelerate CEV development in order to close the gap between the shuttle’s 2010 retirement and the first crewed flight of the new system. The Exploration Systems Architecture Team that Griffin chartered last spring to plot NASA’s path back to the Moon laid out a plan for fielding the CEV in 2011. But by the time Griffin finally unveiled the exploration architecture last September, CEV was on the calendar for 2012. When NASA’s 2007 budget request was unveiled Feb. 6, Griffin said NASA still intended to field the CEV “as close to 2010 as possible and no later than 2014.”

Rep. Ken Calvert (R-Calif.), the chairman of the House Science space and aeronautics subcommittee, voiced support for the way Griffin has played the budget hand he was dealt.

“I think you are on the right track, Mike. I think you do have to have priorities. I think if you ask most people in America what NASA represents I suspect most people would say human spaceflight,” Calvert said. “Science is certainly important. I don’t discount that a bit. But you are faced with a difficult budget and you have to prioritize … and I think you are doing a good job.”

Griffin also testified during the hearing that the $3 billion NASA is requesting for CEV and related systems is more than the agency expects to spend next year. Because NASA has not yet received bids from the two industry teams competing to build the CEV, he declined to reveal during the open forum how much of the requested CEV money would be set aside for later use. He did, however, tell lawmakers that “banking” extra money for CEV now was necessary to level out the funding “peaks and valleys” that lie ahead for the multi billion dollar-development effort.