A new mission to the lunar surface -- possibly establishing a permanent base there -- is the focus of high-level White House discussions on how to reinvigorate the space program following the space shuttle Columbia accident earlier this year, said the officials, who spoke on condition of anonymity.

"NASA, along with other agencies, has been providing the administraion with information about these long-term objectives," Robert Jacobs, a NASA spokesman, said. NASA officials are meeting in Washington this week as part of a national space policy review prompted by the Columbia disaster, which killed all seven astronauts aboard.

While officials stressed that the White House has yet to sign off on a specific plan, they said President Bush is expected to soon unveil a new strategy that would include manned missions to the moon and Mars. The idea is to motivate NASA engineers and researchers by aiming to explore deeper reaches of space than the current shuttle fleet is capable of visiting. Vice President Dick Cheney recently met with members of Congress to discuss the proposals, the officials said.

NASA officials and space specialists increasingly believe that recent American human space flight activities -- particularly the delayed and costly construction of the International Space Station -- do not push the envelope enough to continue motivating researchers and engineers or spark the kind of public fascination with space that was generated by the first missions to the moon. The agency, they fear, risks a continued erosion of public and financial support unless a new objective is established -- one that could take decades to meet.

"I think the idea is fine," James Lovell, whose 1970 Apollo mission to the moon encountered mechanical problems and nearly ended in catastrophe, said in a telephone interview.

"A challenge to go back to the moon and reinvigorate the space flight program would be welcomed by the public," he said. "But the technology that we had in the 1960s and 1970s, such as the Saturn V heavy booster rocket, is no longer available. The actual people, the planning, the tooling, are gone. It would cost us. We'd be starting from scratch."

A return to the moon -- then possibly moving on to a nearby asteroid and, in the longer term, Mars -- would bring with it significant technical risks and tremendous costs, officials said. It remains unclear whether there would be sufficient political and public support to energize such an effort in an era of federal budget deficits. There is also disagreement over the scientific value of sending humans outside Earth's orbit.

"The federal government has too few resources and too many obligations to give NASA a blank check," Representative Sherwood Boehlert, Republican of New York and chairman of the House Science Committee, recently said, giving voice to doubts in Congress about the value of dramatically increasing the space program. "Human exploration is not necessarily the best way to advance science or technology, and it certainly is the most expensive and riskiest way to do so."

Not that there isn't some support on Capitol Hill.

"We urge you to elevate the priority of the space program and develop a bold and coherent national mission for NASA," nearly two dozen senators urged Bush in a letter last month. "We are prepared to support you in the pursuit of a realistic and achievable vision for space flight."

Some specialists say the new vision would require a relatively modest increase in NASA's estimated $15 billion annual budget, perhaps a boost of $5 billion -- particularly if the costly space shuttle program is scrapped in lieu of a new vehicle that can travel farther distances.

Another incentive to head back to the moon is the nascent manned space program of China, which put their first man in space earlier this fall and plans its own lunar mission.

"It's not on the same level of intensity as our program was, but it is certainly serving notice that the nations that dare to build the technology will be able to say what goes on up there," said Paul Cloutier, professor of physics and astronomy at Rice University.

In the scientific community, the discussion revolves around the value of the current manned flight program.

The space station was established to conduct scientific research in space and was expected by some to serve as a way station for missions to deep space. Its expansion is behind schedule and many nations have not fulfilled pledges to support it. Aiming for Mars, advocates of interplanetary travel say, would inspire technological advances and allow research into one of man's most enduring questions: Has life ever thrived on another planet?

"The [International Space Station] is not the expected transportation node for missions beyond Earth orbit that it was supposed to be," Wesley T. Huntress Jr. of the Geophysical Laboratory at the Carnegie Institution of Washington, told the House Science Committee in October. "It has become an Earth-orbital end unto itself. And the space shuttle is not the low-cost, low-risk operational space transportation system that it was supposed to be. The whole point of leaving home is to go somewhere, not to endlessly circle the block."

Cloutier said: "We are in the doldrums, so to speak, and the one thing that the public gets tired of is seeing money spent without a clear indication of whether we are making progress."

Some scientists and officials were skeptical about the plans yesterday, noting that President George H. W. Bush laid out similar goals for the space program in 1991 -- goals that were never backed by a specific plan or funded.

If the current President Bush does call for a return to the moon, the real reason would not be lunar science, scientists said yesterday. Enormous gaps in knowledge about the moon's interior structure, its origin, and geology remain. But the real benefit of returning to the moon, they said, would be as a first step to manned space exploration to Mars.

A mission to the moon would help NASA to make the technological advances needed if humans are to ever embark on interplanetary travel, such as developing nonchemical propulsion systems and systems that would enable human survival in deep space for months or years at a time, specialists said.

It would take at least six months to travel to Mars, specialists said, and astronauts might have to wait more than a year before returning to Earth, depending on Mars's orbit.

"Development of lunar bases on the moon, only three days away, will teach us much of what we need to know to press on to Mars," according to Michael D. Griffin, the former associate administrator of NASA for exploration and a fellow at the American Institute of Aeronautics and Astronautics.

There has long been a debate among space scientists whether or not manned space travel is needed at all. Robotic missions can often accomplish as much scientifically than manned flights can, and at much lower costs. Some academics interviewed yesterday said Mars should be a goal of the space program, but it should be conducted with a robotic instrument and bypass the moon altogether. "Anything that we want to do in space today we can do more cheaply, more safely, and much more effectively with automated spacecraft than sending people, because we turn a research instrument into a life support instrument," said Alex Roland, professor of history at Duke University who studies the space program.

Beth Daley of the Globe staff contributed to this report.