WASHINGTON -- President Bush proposed Wednesday to develop a new spacecraft to carry Americans back to the moon by 2015, and to establish a long-term base there as an eventual springboard to Mars and beyond.
Bush would withdraw the United States from the International Space Station by 2010 and retire the space shuttle fleet at about the same time. Details of his proposal were released by the White House in advance of a speech by the president at NASA headquarters.
Bush wants to use the moon as a base for more ambitious missions to Mars and into the deeper reaches of the solar system, the White House said.
An extended human presence on the moon "will enable astronauts to develop new technologies and harness the moon's abundant resources to allow manned exploration of more challenging environments," the White House said in a prepared statement.
"The experience and knowledge gained on the moon will serve as a foundation for human missions beyond the moon, beginning with Mars," the statement said.
The moon has one-sixth the gravitational field of Earth, so moon-based aircraft could launch from there more cheaply.
"The president's vision affirms our nation's commitment to manned space exploration," the White House statement said. "It gives NASA a new focus and clear objectives. It will be affordable and sustainable while maintaining the highest levels of safety."
Bush proposed a modest increase in spending for the new venture -- $1 billion in new spending over five years. Bush also would shift $11 billion in federal money from other NASA programs to make way for the program.
Probes, landers and other unmanned spacecraft would explore the lunar surface beginning no later than 2008 to research and prepare for future human exploration.
NASA also would develop and build a new Crew Exploration Vehicle to ferry people first to the International Space Station after the shuttles are retired, and then to the moon, no later than 2015. The goal, the White House said, would be humans "living and working there for increasingly extended periods."
White House officials said the human "presence" would not necessarily be a permanent base.
At the start of an election year, the White House cast the next envisioned generation of space travel as affordable and useful to average Americans who might be skeptical about such a mission at a time of record budget deficits.
The administration's fact sheet offered a list of benefits from previous space missions: "Space exploration has yielded advances in communications, weather forecasting, electronics and countless other fields," the White House said. Examples included CAT scanners, MRIs, kidney dialysis machines, programmable heart pacemakers and satellite communications advances.
Bush is asking for a $1 billion boost to NASA's budget over five years to fund the start of a new American campaign in space. White House spokesman Scott McClellan said NASA spending, in the short term, would constitute less than 1 percent of the federal budget, but he would not provide a total price tag for the venture.
McClellan suggested that other countries, perhaps including Russia, would share in the project and help bear the costs. "Russia would have some important contributions," McClellan said.
Bush also formed a new panel, the Commission on the Implementation of U.S. Space Exploration Policy, to advise NASA on the implementation of his ideas.
