Bob Werb, chairman of the Space Frontier Foundation, was blunt in his assessment of the House bill. “I think it’s awful,” he said. “It’s leaving NASA with way more pork than program. I see that as a disaster for the agency.” Mr. Werb’s group is urging its supporters to register disapproval with their Congressional representatives.

By contrast, the president’s budget proposed $6 billion over five years for the commercial crew program.

At Wednesday’s news conference, Boeing officials said that the federal government would have to pay much of the development costs in order for the effort to succeed. “This is an uncertain market,” said John Elbon, program manager for Boeing’s commercial crew effort. “If we had to do this with Boeing investment only and the risk factors were in there, we wouldn’t be able to close the business case.”

The tight constraint, of course, is money.

Last year, a panel led by Norman R. Augustine, a former chief executive of Lockheed Martin, concluded that the ambitious program started under President George W. Bush to establish a permanent moon base was “not executable” because of inadequate financing. In fact, the panel could not devise any program that could send astronauts beyond low-Earth orbit and still fit within the $100 billion allocated to the human spaceflight program in the fiscal years of 2010 through 2020. It offered several alternatives that would require an extra $30 billion over the next decade.

Mr. Obama’s budget request for 2011 sought a modest increase in NASA over all, to $19 billion, but kept the budget projections for the human spaceflight program almost unchanged from the levels that the Augustine panel found inadequate. The panel said that without an increase, the United States should scale back its space ambitions.

“With that budget,” Mr. Augustine said in an interview this summer, “I still think there is no really meaningful space exploration program that involves humans.”

The administration worked around the budget shortfall by proposing the cancellation of the entire moon program, known as Constellation, including the Ares I rocket and the Orion crew capsule. Instead, NASA would essentially take a five-year hiatus from large-scale development initiatives and instead work on new technologies that could make the task of space exploration easier and cheaper.