WASHINGTON — Adding to the uncertainty surrounding NASA’s human spaceflight program, a House appropriations panel on June 29 voted to fully fund the U.S. space agency’s $19 billion budget request for 2011 but then fenced off most of the $4.2 billion included for manned space exploration, making the money off limits until a new NASA authorization bill is enacted.

“Any major change to the direction of the nation’s space program should come through an authorization passed by Congress,” Rep. Alan Mollohan (D-W.Va.), chairman of the House Appropriations commerce, justice, science subcommittee, said in opening remarks at the legislative mark-up session. Mollohan said it was unfortunate that NASA’s manned spaceflight plans have been “effectively on hold for over a year.”

U.S. President Barack Obama last year ordered a review of the agency’s Constellation program, a 5-year-old effort to replace the retiring space shuttle with new rockets and spacecraft optimized for returning astronauts to the Moon. Obama then proposed canceling Constellation in his 2011 budget request to Congress in February, but revived the program’s Orion Crew Exploration Vehicle in April to serve as a lifeboat aboard the international space station.

Spending legislation enacted last year bars NASA from canceling Constellation or standing up new programs in its place until Congress passes new legislation approving the change of plans.

NASA authorizing committees in both the House and Senate have pledged to pass NASA legislation this year. Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce science and space subcommittee, is expected to introduce a NASA authorization bill in mid-July. House Science and Technology Committee Chairman Rep. Bart Gordon (D-Tenn.) has said his committee would pass a NASA authorization bill this year, although the timing is unclear.

In the absence of authorization legislation, “this subcommittee has no business in appropriating even more funding for uncertain program outcomes,” Mollohan said. “Accordingly, this bill makes the funding for human space exploration available only after the enactment of such authorization legislation.”

Following the mark-up, a subcommittee staff member explained that despite the restriction on NASA’s human spaceflight funds, roughly $300 million would be available for the Commercial Orbital Transportation Services (COTS) program. NASA requested $312 million in 2011 to provide incentives to the agency’s two COTS providers and reduce risk in the 4-year-old program.

Rep. Robert Aderholt (R-Ala.) said in a statement following the mark-up that other than the money for COTS, “Congress is still not comfortable moving forward with the president’s plan.” Aderholt is one of a number of U.S. lawmakers who represent states that stand to lose thousands of jobs when the space shuttle is retired next year.

Constellation was meant to absorb a sizeable fraction of those workers, but NASA has already slowed spending on the program and compelled contractors to reserve remaining funds to cover closeout costs. In response, Aderholt and more than a dozen other lawmakers, including Rep. Ralph Hall (R-Texas), ranking member of the House Science and Technology Committee, introduced a bill that would force NASA to continue spending 2010 funds appropriated for Constellation contracts rather than setting the money aside to cover contract termination costs.

NASA Administrator Charles Bolden wrote U.S. lawmakers June 9 that the agency planned to slow work on its Ares 1 rocket and other parts of Constellation to address a nearly $1 billion shortfall the program is facing as a result of contractors failing to fully account for costs they could incur as a result of having to lay off employees and shutter facilities if the program is shut down. Bolden estimated that 2,500 to 5,000 contractors could have to be reassigned or laid off as a result.

NASA averted some Constellation layoffs with fresh funds released to select contractors in June, according to agency officials. On June 1, NASA’s Johnson Space Center made an $18.1 million “progress payment” to Houston-based Oceaneering International Inc. to continue work on the Constellation Space Suit System. Johnson also paid $83 million to Denver-based Lockheed Martin Space Systems June 15 for work on the Orion Crew Exploration Vehicle, which Obama envisions using as a crew lifeboat aboard the international space station and as the technological foundation for a deep space capsule.

On June 16, NASA’s Marshall Space Flight Center in Huntsville, Ala., paid Minneapolis-based Alliant TechSystems $161 million in progress payments to continue work on the Ares 1 first-stage contract that Obama plans to abandon in the fiscal year that begins Oct. 1.

Aderholt said that as lawmakers continue to debate Constellation’s future, program contractors are pink-slipping workers and canceling orders under “intense pressure from NASA regarding contract termination liability.” If Congress ultimately rejects the Obama proposal and directs NASA to continue Constellation, “it will be very difficult to reassemble the lost jobs and scaled down contract work.”

In March, Aderholt and other lawmakers called for an investigation by the U.S. Government Accountability Office (GAO) into the legality of NASA’s actions toward the Constellation program. GAO’s first of a two-part response confirmed that while NASA had not violated the law in planning for post-Constellation activities, agency personnel had devoted “a significant amount of time, roughly 13,000 staff hours of high-level employees, on a plan which Congress has not approved yet,” Aderholt asserted in his news release.

GAO is continuing to investigate whether NASA is improperly withholding funds for the program by applying the Anti-Deficiency Act as a means of slowing progress on Constellation work. GAO’s findings are expected in the coming weeks, according to Aderholt’s statement.