WASHINGTON—The federal budget squeeze has forced NASA to abandon hope of launching a successor to its three aging space shuttles by 2014, the target that President Bush set in his "Vision for Space Exploration" plan three years ago.
Instead, the United States will have to rely on Russia or commercial aerospace companies to ferry cargo and crews to the International Space Station for five years after the last shuttle is retired in 2010.
The shuttles' replacements—the new Orion spaceship and Ares I rocket launcher—won't be ready until 2015 at the earliest, NASA Administrator Michael Griffin told the House Science and Technology committee Thursday.
"America may have a prolonged gap between the end of the shuttle program and the beginning of Orion and Ares I operational capability," he said.
"I cannot sugarcoat the issue," Griffin told a House Appropriations subcommittee Tuesday. "I am deeply concerned that the gap between the retirement of the space shuttle in 2010 and the new U.S. human spaceflight systems does not grow longer."
The lengthening time that the United States won't have the means to put humans into space is an embarrassment for the world's leading space-faring nation, especially when other countries are stepping up their extraterrestrial ambitions.
"If the new spacecraft are delayed even further," Griffin said, "the nation will cede leadership in human spaceflight at a time when Russia and China have such capabilities, and India is developing them."
The setback comes as budget reductions force NASA to delay or cut back some of its popular science goals, including climate-change research and the hunt for habitable planets around other stars.
"I'm afraid NASA is heading for a train wreck if things don't change," Rep. Bart Gordon, D-Tenn., the chairman of the science committee, told Griffin on Thursday. The space agency's new budget, he said, "bears little resemblance to the rosy projections offered by the administration three years ago."
NASA has spent about $9 billion for space exploration since Bush announced his "Vision" in January 2004. The agency is running almost $1 billion short of the amount it originally projected to spend through 2014.
The space exploration budget for the coming year, fiscal 2008, is $3.9 billion, $229 million less than the White House had sought for 2007. That comes on top of a $751 million shortfall this fiscal year because Congress failed to agree on a spending plan for 2007.
NASA is committed to a pay-as-you-go process. "If we receive less funding than requested, we will adjust our pace," Griffin said.
During the two and a half years that the space shuttles were grounded after the Columbia disaster in 2003, NASA relied on Russia's small Soyuz vehicle to carry astronauts to and from the space station. Another Russian craft, Progress, handled cargo loads.
NASA has contracted with two American aerospace companies to develop a commercial spaceflight system for humans and cargo. The partners, Space Exploration Technologies of El Segundo, Calif., and Rocketplane-Kistler of Oklahoma City, together will get about $500 million to develop a low-cost replacement for the shuttles.
The first commercial test flight is scheduled for the fall of 2008, with a three-day unmanned mission to mate with the space station a year later.