WASHINGTON — U.S. President Barack Obama’s plan to scrap NASA’s Moon-bound Constellation program and turn to private companies for launching astronauts into space provoked a strong bipartisan rebuke from the Alabama, Florida and Texas congressional delegations several days before the president was slated to deliver his annual budget request to Congress.

House and Senate lawmakers from the three states home to NASA’s lead human spaceflight centers unleashed a barrage of criticism in advance of the Feb. 1 release of Obama’s 2011 budget request, which an administration official said would increase NASA spending by $6 billion over the next five years, keep the international space station in service through at least 2020, cancel the agency’s 5-year-old Constellation program to build new rockets and spacecraft optimized for the Moon and fund a $6 billion effort to foster development of commercial systems for ferrying astronauts to the international space station.

Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce Committee panel that oversees NASA, said in a Jan. 29 statement that if reports of the White House plan are accurate, “then the president’s green-eyeshade-wearing advisors are dead wrong.”

Nelson, whose state is home to Kennedy Space Center, said he would “fight for NASA, and for the thousands of people who stand to lose their jobs.”

Rep. Bill Posey (R-Fla.) called Obama’s plan “a giant leap backwards” and Rep. Suzanne Kosmas (D-Fla.) said it was “simply unacceptable” and vowed to “fight back” to preserve Kennedy contractor jobs that stand to be lost when shuttle flights end.

Texas lawmakers were similarly disgruntled about the plan and what it might mean for NASA’s Johnson Space Center, which has been in charge of the Constellation program since its 2005 inception. Republican Reps. Ralph Hall, Pete Olson, and Michael McCaul and Democratic Rep. Sheila Jackson Lee all issued testy press releases in the wake of media reports about the president’s NASA plans.

Sen. Mary Landrieu (D-La.) said she would try to shield work at NASA’s Michoud Assembly Facility in New Orleans from any job losses associated with the Constellation program’s cancellation. Michoud workers have been counting on Ares and Orion to make up for the loss of the space shuttle external tank work done there.

Sen. Richard Shelby (Ala.), the ranking Republican on the Senate Appropriations commerce, justice, science subcommittee, said canceling Constellation and turning over crew transportation to the private sector threatens to make the astronauts launched on NASA’s final shuttle mission in September the last Americans sent into space from U.S. soil until well after 2020.

“China, India, and Russia will be putting humans in space while we wait on commercial hobbyists to actually back up their grand promises,” Shelby said in a Jan. 29 statement to Space News, referring to companies banking on NASA to guarantee a market for the  space transportation systems they seek to develop. Shelby, whose state is home to NASA’s Marshall Space Flight Center in Huntsville, where the Constellation program’s Ares 1 and Ares 5 rockets are currently in development, dismissed the proposed $6 billion commercial crew initiative as  “a welfare program for amateur rocket companies with little or nothing to show for the taxpayer dollars they have already squandered.”

Brett Alexander, president of the Commercial Spaceflight Federation here, said Obama’s proposed $6 billion investment would not only get astronauts back to launching on U.S. vehicles faster than Constellation, but would also “create more jobs per dollar” by leveraging private investment.

Alexander said Constellation has failed to live up to the Vision for Space Exploration he helped craft as a White House policy analyst under former President George W. Bush.

“I was a primary author of the Vision for Space Exploration, and I really wanted it to succeed. I am not happy that five years later it has to be retooled completely,”  Alexander said. “But they chose the most expensive architecture and they had cost and technical issues with it. The cost overruns are astonishing.”

A White House panel appointed last year to review NASA’s human spaceflight plans said Constellation was well-managed and technically feasible but likely to cost more than the nation would be willing to spend. The panel suggested the White House consider canceling Ares 1 and foster development of commercial crew systems instead.

John Logsdon, a space policy expert here familiar with Obama’s plan, said the emphasis on commercial crew does not mean that NASA will neglect development of the type of heavy-lift rocket it will need to conduct manned missions beyond low Earth orbit by the early 2020s. In the near term, he expects to see NASA invest in heavy-lift technology and do more to engage its international partners.

“It’s a fairly sophisticated strategy, in saying let’s spend technology money for the next few years, let’s see what our partners might be willing to contribute, and then, let’s choose a design for the heavy-lift vehicle,” he said.