WASHINGTON -- NASA made official on Wednesday its next vision for space travel by unveiling plans for a massive rocket it hopes can blast astronauts to an asteroid by 2025 while laying the foundation for a future trip to Mars.
The new rocket, a hybrid of the space shuttle, would cost at least $30 billion through 2021 and was billed by NASA as the most powerful in its history, more robust than even the Saturn V rocket that carried Apollo astronauts to the moon.
The agency has targeted an unmanned test flight for 2017 with a second, crewed flight in 2021, though no destination has been selected for either flight.
"The next chapter of America's space-exploration story is being written today," said NASA Administrator Charlie Bolden. "Today I am pleased to announce that NASA has selected the design of its new deep-space system that will take American astronauts further into space than any nation has gone before."
What remains to be seen, however, is whether NASA can keep the new project on budget and maintain public support for a mission that won't launch a crew for a decade.
Another question is how NASA will pay for additional exploration tools, such as landers, which astronauts would need once the new "Space Launch System" gets them off Earth.
"Rockets are tools. Asking whether it's a good or bad tool is beside the point. The question is -- what is the job? What's it for? What are we doing? I haven't seen a budget scenario in which there is funding for SLS (Space Launch System) and also funding for missions for us to do with it," said Jeff Greason, a member of a 2009 presidential panel that examined NASA's future.
The new rocket's design includes an external fuel tank and twin boosters, similar to the space shuttle, with the plane-like orbiter replaced by an Apollo-like capsule atop the tank and a new second stage.
Previously, administration sources had hinted its initial flights would loop around the moon -- but not land. The only definite is that NASA still intends to send astronauts to an as-yet undesignated asteroid by 2025, a goal set by President Barack Obama last year.
"We got to do some searches for asteroids to identify targets. As we look more, we find more and more potential candidates. We need to do some more discovery to see where those targets are," said Bill Gerstenmaier, associate administrator for NASA's Human Exploration and Operations Mission Directorate.
The announcement comes at a time of new constraints on the federal budget. Obama has asked agencies to submit 2013 budget requests that are 10 percent below their 2011 levels -- essentially a $1.85 billion cut to NASA.
At $3 billion a year, the new spaceship would fit within a reduced NASA budget, but future cost overruns could mean NASA having to cannibalize other programs to pay for it -- not a rarity for the agency. The Congressional Budget Office has found that NASA cost overruns of 50 percent or more are commonplace.
NASA's last attempt to replace the shuttle with a government-built spacecraft, a moon program called Constellation, was canceled after five years and more than $13 billion was spent on it -- although pieces of Constellation, such as the capsule, remain in the current program.
"The days of unaccountable calendar and cost overruns are over, and I look forward to working with my colleagues in the House to hold NASA accountable for the future of human spaceflight and job creation on Florida's Space Coast," U.S. Rep. Sandy Adams, R-Fla., said in a statement.
Much of the new spacecraft won't be up for competition, either.
The agency has settled on a crew capsule built by Lockheed Martin. And the new rocket's twin boosters, at least initially, would be the same shuttle boosters built by Alliant Techsystems of Minnesota.
New ones -- perhaps liquid-fueled -- would be selected in a competition, the agency said.
The plans also allow the rocket to grow, from a vehicle capable of lifting 70 to 100 metric tons -- as much as four times the shuttle's capacity -- before evolving to a lift capacity of 130 metric tons, according to NASA.
It's a plan championed by U.S. Sen. Bill Nelson, D-Fla., who said the benefits were more than what could fit on a budget ledger.
"In the bosom of every American, there is a yearning for us to explore the heavens."