"President Bush vowed yesterday to "extend a human presence across our solar system," starting with a return to the moon within 16 years to build a permanent staging ground for manned missions to Mars and planets beyond.

The election-year plan calls for retiring the three remaining space shuttles by 2010, after the international space station is complete. Bush wants to develop a manned exploration vehicle to travel to the moon and farther, and he made a commitment that Americans would return to the moon between 2015 and 2020.

In a concession to objections in Congress and elsewhere that such an audacious goal is out of place in an era of deep deficits, Bush said the research and development for the exploration venture can be done for relatively little over the course of this presidential term and the next one -- $12 billion over five years, just $1 billion of which would be new money for NASA. Bush's plan would gradually shift more and more of the space agency's budget and resources to the lunar and Mars missions and away from the space shuttle and space station.

The Pentagon and private companies will collaborate with NASA on the venture. Bush invited other countries to join, and officials said Russia has already expressed interest.

"We may discover resources on the moon or Mars that will boggle the imagination, that will test our limits to dream," Bush said. "We do not know where this journey will end, yet we know this: Human beings are headed into the cosmos."

Administration officials said they hope the astronauts will find traces of water on the moon that could be converted to hydrogen fuel and oxygen to propel spacecraft through the solar system.

The president's speech was a major morale boost for an agency still struggling to recover from disintegration of the space shuttle Columbia on Feb. 1, and seeking to resume flights of the three remaining shuttles. The Columbia Accident Review Board concluded last summer that serious problems in NASA's management culture were as much to blame for the loss of the seven astronauts as a foam strike that left a gaping hole in the shuttle's left wing.

"This resolves the question of what is the vision," NASA Administrator Sean O'Keefe said at a briefing after Bush spoke. "This is what it is."

Officials acknowledged that the project carries great risk and said they have not determined how to shield astronauts from the high radiation levels in outer space and how to counter the physiological effects of prolonged weightlessness.

The White House plan calls for the use of robots for preliminary forays to the moon, which could begin by 2008. The long-term goal would be to establish a permanent colony and scientific laboratory on the moon, where astronauts would live and work for extended periods, then push on to Mars.

Bush, who called for "a new course for America's space program," plans to seek an average increase of 5 percent a year for the next three years in NASA's current $15.4 billion budget.

Bush's new space policy had a partly political genesis, with presidential advisers saying that it emerged from a White House search for a bold goal that would help unify the nation before Bush's reelection race and portray him as visionary. Officials said that Bush had always planned to reexamine NASA's mission, but the disintegration of Columbia was the immediate catalyst.

The president's promised "new era of discovery" was developed by a multi-agency group, coordinated at the National Security Council. Officials said the lunar and Mars program will have a military component, noting that the Pentagon will be consulted and may help with launches.

Republican officials said conservative lawmakers who might balk at the cost are likely to be lured by the chance to extend the U.S. military supremacy in space when China is pursuing lunar probes and Russia is considering a Mars mission.

The president spoke at NASA headquarters after meeting 18 current and former astronauts, some of them in flight suits. Before Bush spoke, he was greeted on an overhead screen by Michael Foale, commander of the international space station, which is 240 miles above Earth. "It's difficult to drop in for a quick visit," Foale quipped.

Bush spoke in front of screens that gave viewers the impression of mission control, with one of the images showing workers applauding his speech as they watched on giant screens at the Jet Propulsion Laboratory, the NASA branch in Pasadena, Calif., where scientists are managing the Mars rover that landed safely two weeks ago.

"We will build new ships to carry man forward into the universe, to gain a new foothold on the moon and to prepare for new journeys to worlds beyond our own," Bush said. "With the experience and knowledge gained on the moon, we will then be ready to take the next steps of space exploration: human missions to Mars and to worlds beyond."

The administration outlined a piecemeal program that had no overall price, although a chart released by NASA suggested it could add up to as much as $170 billion by 2020. Bush's aides were eager to avoid the mistake made by his father, who in 1989 proposed establishing a base on the moon, sending an expedition to Mars and beginning what he described as the permanent settlement of space. NASA responded with a plan estimated to cost as much as $500 billion over decades, and Capitol Hill rejected the plan.

The president's strategy appeared to be working yesterday, as several key lawmakers said Bush's plan seemed affordable.

"Sure, the money is a big question," said House Science Committee Chairman Sherwood L. Boehlert (R-N.Y.). "But I think the president was realistic."

Bush's speech was a president's most ambitious articulation of a space vision since 1961, when John F. Kennedy called the nation to send a man to the moon by the end of the decade. That was the height of the Cold War, and the United States was bent on beating Russia.

Eugene A. Cernan -- commander of the crew members of Apollo 17, who in 1972 were the last humans to set foot on the moon -- said in an interview that NASA has lacked a long-range, reachable goal. "We haven't had a space program," said Cernan. "We've had a series of space events."

While the public and Congress continue to support manned space flight in the wake of the Columbia space shuttle disaster, polls suggest there is widespread skepticism about the president's plans for an aggressive and costly new program.

In an effort to overcome congressional doubts about NASA, Bush appointed Edward C. "Pete" Aldridge Jr., former secretary of the Air Force, to head a commission of private- and public-sector experts to offer advice on the implementation of his vision.

O'Keefe said officials are still determining how much of the project would be done "in-house" by NASA and how much would be done by partners, including universities, and whether there would be "an industry-driven approach." (Mike Allen and Eric Pianin, The Washington Post, January 15, 2004)