Let's put the bottom line right at the top. The Bush administration is unwilling to provide the funds necessary to fulfill its Vision for Space Exploration.

The reasons--whether Iraq, Katrina, or the president didn't really mean it--don't matter. The White House wants U.S. obligations to the international space station partners to be honored, the space shuttle flown as many times as necessary to complete the station's construction, and a replacement for the shuttle (the Crew Exploration Vehicle, or CEV) flying by 2014. All very laudable goals in principle, but not so if the funds are not provided.

The administration has handed these goals to NASA without the funds necessary to accomplish them. NASA's human spaceflight program was left $3 billion to $5 billion short for flying the desired number of shuttle flights and completing space station construction. This dilemma has forced the NASA administrator to cannibalize the rest of the agency for the money. Last year he tapped aeronautics and technology. This year all that is left to pay the bill is science.

The administration's 2007 budget proposal removes $3.07 billion from the previously planned five-year run out of the Earth and space science budget. Of this, $2.99 billion is to come from solar system exploration alone -- only one of the several science disciplines in NASA and ironically one of the most relevant to human exploration.

This cannot be done without causing serious harm both to robotic exploration and to a space science community that should, and needs to be, a partner with human exploration. As a NASA official once said: "Exploration without science is just tourism."

In the press conference explaining the budget, officials cited the growth of space science in NASA from about 21 percent of the budget in 1992, to 32 percent today. But, during that same time period, space science has been carrying the agency exploration flag, and the agency has been rightly proud of the productivity of the Earth and space sciences. Missions such as Hubble, Mars Exploration Rovers and Cassini/Huygens are indeed, as NASA Administrator Mike Griffin himself said, the "crown jewels" of NASA.

Griffin vowed never to transfer "one thin dime" from scientific exploration into human spaceflight. He has been forced to renege on that promise. Now, in the administration's fiscal year 2007 budget request, we have a sudden, wrenching decision to flat-line science, and no soft landing has been provided.

There are to be many delays in science flight programs and many "deferrals beyond the budget horizon" (read cancellation) in others. It's a long list and you will hear about them all soon enough. There is even to be more "rebalancing" of the Mars program, most of whose growth was removed last year. Missions, technology development and research aimed at Mars exploration have been reduced and eliminated, proving that the agency has all but abandoned the vision's Mars goal for human spaceflight.

NASA needs reminding that the vision is not just about human spaceflight. The very first goal stated in the vision is to "implement a sustained and affordable human and robotic program to explore the solar system and beyond." The vision further advocates that we "conduct robotic exploration across the solar system for scientific purposes and to support human exploration."

But as bad the mission delays and deletions are, this budget proposal makes a full frontal attack on basic science. It proposes to cut NASA's Earth and space science research grant programs by 15 percent across the board. Astrobiology, NASA's newest and most innovative research program, is targeted for a 50-percent cut. And all cuts are immediate--today, in the 2006 budget year. Grants are to be reduced immediately, dimming the prospects of many young, motivated students. What kind of message is that to the best and brightest of America's hopes for a rich technological future? Ironically, this comes days after the president called for increased spending on the physical sciences.

These research programs make NASA's flight missions possible and turn raw data into discoveries. Without them, the missions are just engineering exercises. The excuse for this unprecedented cut is that since the flight programs are being delayed and deferred, we don't need the research. Would it have made sense in 1905 to tell Einstein to stop his research and go flip burgers just because we don't need relativity right now?

A mission loss affects a few institutions, a few scientists and a few congressional districts. But an across-the-board reduction in research grants hurts every Earth and space scientist in the country. These stakeholders reside mostly in universities in a large percentage of congressional districts in the nation. Mission losses aside, this is an assured way to alienate the science community just when its support is so urgently needed.

NASA appears desperate to preserve the illusion of the vision. The administrator's budget message said about the vision, "we will go as we can afford to pay." But the administration won't pay, and NASA is going forward anyway even when they can't afford to pay for it--by gutting science and robotic exploration. Who will be led to the budget guillotine next year when development costs rise in human spaceflight or if the shuttle suffers more problems?

Wesley T. Huntress, Jr. is president of The Planetary Society and director of the Geophysical Laboratory at Carnegie Institution of Washington; he is the former NASA associate administrator for Space Science. Louis Friedman is executive director of The Planetary Society. He was former congressional science fellow of the Senate Committee on Commerce, Science and Transportation. If you agree with this article, join the Planetary Society's NASA 2007 Budget Letter Writing Campaign.