NASA unveiled a 13-year, $104-billion blueprint Monday for sending humans back to the moon as early as 2018, using a modified space shuttle rocket to propel an Apollo-like capsule into space.
Analysts said the design was decidedly retro, harking back more than three decades to the Cold War's moon race.
But they said the new design was safer and more realistic than the current space shuttle, which is scheduled to be retired in 2010 after nearly 25 years of service and two disastrous shuttle losses.
"Think Apollo on steroids," NASA Administrator Michael D. Griffin said during a news conference at the agency headquarters in Washington.
The blueprint unveiled Monday is part of a broader initiative launched by President Bush 18 months ago, in which he called for returning humans to the moon as a steppingstone to a manned mission to Mars, perhaps as early as 2020.
The new capsule, known as the crew exploration vehicle, would be significantly larger than the cramped Apollo capsule, with seating for up to six astronauts instead of three.
Due to launch in 2012, it would initially be used to resupply and transfer International Space Station crews after the shuttle is retired, NASA officials said.
Unlike the winged shuttle that is mounted on the side of a fuel tank attached to two rockets, the capsule would sit atop a rocket, away from falling debris and potential rocket explosions that doomed the shuttles Columbia in 2003 and Challenger in 1986.
NASA officials estimated that the new craft would be 10 times safer than the space shuttle. The agency estimated that a space shuttle would be lost about every 220 missions. The new vehicle will be designed to be used in more than 2,000 missions without a serious calamity.
In 2018, NASA would launch the first back-to-the-moon mission with a new lunar lander and other components that would allow for up to four astronauts to stay on the surface for up to seven days.
The Apollo missions, which cost $150 billion, focused primarily on landing astronauts on the moon for a day or two and then returning them to Earth.
Elliot G. Pulham, president of the nonprofit Space Foundation, a space exploration advocacy group, called the blueprint a "challenging yet realistic plan" that doesn't "break the bank."
But questions about how NASA would sustain public interest and win funding from Congress for more than a decade dogged the unveiling Monday.
Some observers worried that huge federal spending on such items as rebuilding New Orleans, which could cost up to $200 billion, could undermine funding for any major space initiatives.
"If you're not going to have a lunar landing until 2018, how are you going to keep people and Congress interested?" said John Pike, a space policy analyst for GlobalSecurity.org.
But Griffin said the nation could afford the price tag because he would not seek any new money for the agency's annual $16-billion budget.
Instead, spending within NASA's human spaceflight program would be redirected to pay for the endeavor, he said. About $4 billion to $5 billion a year is now allocated for manned spaceflight.
Measured in constant dollars, the $104-billion price tag, spread over 13 years, represents 55% of what the eight-year Apollo program cost, Griffin said. The objective, he said, was to "pay as you go and what you can afford."
"There will be a lot more hurricanes and a lot more other natural disasters to befall the United States," Griffin said. "We must deal with our short-term problems while not sacrificing our long-term investments in our future."
NASA's announcement created a buzz among enthusiasts at the International Lunar Conference in Toronto on Monday.
"We've got to go" back to the moon, said Buzz Aldrin, a former Apollo astronaut who made the first manned moon landing with Neil Armstrong in 1969. "But we don't want to stay too long....The ultimate goal is Mars."
Although the design for the new crew exploration vehicle would resemble the Apollo capsule, the spacecraft would be three times as big, NASA officials said.
On its return to Earth, it would be able to make a soft terrestrial landing by parachute, perhaps at Edwards Air Force Base in the Mojave Desert, instead of splashing down at sea. It would be reused several times.
"Much of it looks the same," Griffin said, but added, "It's a significant advancement over Apollo."
The return mission to the moon would also differ from the Apollo missions in several ways.
Unlike the Apollo program, which relied on the massive Saturn V rocket to loft both the capsule and the lunar lander, NASA plans to send up two rockets, one carrying the crew capsule and the second the lunar lander and other components.
The crew capsule rocket would be a modified solid rocket booster used on the space shuttle, while the cargo rocket carrying the lunar lander would be consist of a modified shuttle engine, external fuel tank and solid rocket boosters.