As NASA sets its sights on returning to the Moon, the U.S. space agency wants to make sure the scientific research done there is no mere afterthought, but a well-conceived program developed in close consultation with the scientific community.

To make sure that happens NASA has asked the National Academy of Sciences to develop a prioritized list of science goals for the lunar orbiters and landers that the agency intends to send to the Moon starting in 2008, as well as the initial human sorties slated to begin 10 years later. Draft recommendations are due to NASA later this summer with a final report expected to be published in early 2007.

The ad hoc committee of 15 scientists in charge of producing the forthcoming report, "The Scientific Context for the Exploration of the Moon," met here June 20-22 to get that work started. Paul Hertz, chief scientist for NASA's Science Mission Directorate, instructed the committee to focus on science objectives that could not be done anywhere else.

"I'm sure there is a lot of great science that can be done on the Moon that can also be done elsewhere," Hertz said. "We'd like to pay particular attention to the science that can best or only be done on the Moon. It's a unique and expensive opportunity, and we want to make sure we are concentrating our limited resources on the highest priorities that can be enabled by this program."

For example, Hertz said that when people suggest putting a telescope on the Moon, he tells them "the real question is 'would you rather have that telescope at the Moon or this telescope in orbit?' because those are the choices we will be making."

"We don't have extra money for an extra telescope," Hertz said. "So the question isn't what telescopes can you do from the Moon, it's which astrophysics is best done from the Moon as opposed to orbit, the surface of the Earth or other venues. And that's true for all of the science."

Hertz, who was filling in for Mary Cleave, NASA's associate administrator for science, said any science objectives the committee proposes would have to compete for funding against already-established science priorities.

"The exploration program is not science driven but we want to do as much great science as we possibly can within the resources that are available to us," Hertz said, later adding: "There is no augmentation to the science budget to execute any science opportunities that are enabled by exploration no matter how important they are."

NASA's $5.3 billion-a-year science budget is projected to grow at less than the rate of inflation through at least the end of the decade, even as marquee programs such as the $4.5 billion James Webb Space Telescope require more funding.

As recently as last year, NASA had told scientists that their share of the agency's budget would continue to grow by 5 percent to 7 percent annually. NASA's abrupt reversal, although primarily driven by the space shuttle program's greater-than-expected funding needs, has prompted broad segments of the scientific community to blame the agency's space exploration goals for their diminished budgetary prospects.

Hertz acknowledged the scientific community's skepticism about the scientific importance of U.S. President George W. Bush's Vision for Space Exploration when he stressed to the National Academy committee the importance NASA places on engaging the community in formulating sound science goals for the Moon program.

"We want to always be doing outreach to the communities so they recognize that this isn't just some little tidewater activity that we are spinning off because the president decided that the nation is going back to the Moon, but in fact this is part of our integrated science program," Hertz said. "Outreach is important or else I think we are going to end up with a situation like much of the history of the space station was where the science community was against it, OK, because they didn't see the value of the science because the science wasn't established with bona fides that they recognized."

Hertz also said the way NASA plans to go about formulating its lunar science program is at least as important as the content itself.

"It is important that as the agency starts to put together the science program that will accompany and is enabled by exploration, it have a firm foundation on what the community recognizes as well-posed, well-founded, high-priority science and that the priorities were arrived at through the kind of processes that they recognize and put great faith in," Hertz said. "We don't want to do a top-down science program because we don't believe that even if it was the same program, that the science communities would recognize it as a quality science program."

In parallel to the National Academy effort, the NASA Advisory Council also will be taking a close look at lunar science objectives, Hertz said. And in the months ahead, NASA plans to solicit proposals from the scientific community for concept studies focused on research payloads -- so-called surface science packages -- that could be sent along with the astronauts conducting the initial lunar sorties expected to commence around 2018.

Hertz said NASA hopes to award a half-dozen or more yearlong study contracts. "We would like to engage the science community now in thinking about what kind of good science can be done on the Moon and create a little buzz hopefully about some funded opportunities in the near term."

"We recognize that articulating a compelling and important science program is critical to the success of bringing the science community on as partners as we take advantage of the opportunities that are enabled through the exploration program," Hertz added.

A chart Hertz used in his presentation to the group made the point even more strongly, saying "weak science would be questioned and could jeopardize the entire program."

When the committee's co-chair, Brown University planetary scientist Carle Pieters, asked Hertz about the "inconsistencies" of a space exploration initiative that is not science driven, yet dependent on a strong science program for its continued existence, Hertz backpedaled a bit.

"Maybe 'entire lunar program' is too strong," Hertz said. "But as I said before, I don't want to be in the position of having the science community antagonistic to the lunar program. I want them to be enthusiastic because the science that's being done is important science. I want us to establish the science component of the lunar exploration activities in the right way, to do the best science so that [those in] the science community are willing and enthusiastic partners for this."

That may take some doing given how reluctant some scientists are to get behind what many derisively refer to as "another space station" -- a big, expensive undertaking that demands near-term sacrifices in exchange for eventual scientific riches slow to materialize.

A particularly skeptical note was sound by committee member Anthony England, a former NASA astronaut who helped develop radars used to probe the Moon on Apollo 17.

"This sounds like the discussion from early space station where you are trying to satisfy everybody's goals and then eventually you don't satisfy anybody's," England said.