Lawmakers took more shots Wednesday at NASA's plans to turn over human spaceflight to commercial operators, and some members of Congress questioned whether the agency broke the law by deferring some work on the scrapped Constellation program.

"We are here today because the president's budget has been found deficient by this Congress and by the American people," said Rep. Gabrielle Giffords, D-Ariz., chairwoman of the House Science and Technology Committee's subcommittee overseeing NASA.

The subcommittee's hearing Wednesday discussed Congress's roles in crafting NASA's human spaceflight policy.

Thomas Young, a respected former aerospace executive, said commercial companies will not be ready to take over human space transportation in the near future.

"I believe we are a long way from having a commercial industry capable of satisfying human space transportation needs," Young said in prepared testimony. "In my view, this is a risk too high and not a responsible course. The commercial crew option should not be approved."

NASA officials previously stated they expected private firms to be ready for duty by 2016. Some companies, including SpaceX, claim they can field a human-rated spacecraft within about three years.

Pete Olson, a Texas Republican and ranking minority member of the House Subcommittee on Space and Aeronautics, said he believes commercial space travel providers should enter the business incrementally. The companies should first demonstrate their ability to deliver cargo to the International Space Station before being entrusted for piloted missions, according to Olson.

Rep. Dana Rohrabacher, R-Calif., was the lone voice on the House panel supporting the transition of human spaceflight to commercial firms.

"If we are going to be in space, we had better do it cost-effectively," Rohrabacher said. "And cost-effectively is not relying on the government. It's better to go with commercial and private people rather than a federal bureaucracy."

Lawmakers also questioned whether NASA has followed a law requiring Congressional approval of changes in the Constellation program.

NASA has held off on procuring early contracts for the Ares 5 rocket and the Altair lunar lander, delayed an engineering and ground services contract at the Kennedy Space Center, and directed Ares 1 contractors not to award subcontracts to other companies, according to Giffords.

Giffords cited language in NASA's fiscal year 2010 appropriations bill asserting Congressional control over the Constellation program.

"The bill requires that any program termination or elimination or the creation of any new program, project or activity not contemplated in the budget request must be approved in subsequent appropriations acts," legislators wrote in the budget bill's summary report last year.

Olson said the contract actions go against the spirit of the law, but Doug Cooke, a senior NASA manager, told the House subcommittee the agency is acting within the law.

"We are not directing the contractors to take actions [that are not in the contracts]," Cooke said.

NASA Administrator Charles Bolden told a House appropriations subcommittee Tuesday that his legal advisors agree the agency is complying with the legislation. Bolden also said he welcomed a pending Government Accountability Office investigation into whether NASA is violating law by formulating new plans and deferring some Constellation activities.

Cooke said a number of the contract delays were ordered last year as the Augustine commission began its independent review of the human space program.

"The marching orders now are [for] Constellation," Olson said. "That's what the appropriations bill language says. Until that changes, that's it."

A Senate appropriations subcommittee hearing on NASA was to be held Thursday morning, but lawmakers have rescheduled the event until April.