WASHINGTON — The Senate Commerce Committee approved legislation July 15 that would slow a White House plan to utilize privately developed vehicles to ferry astronauts to and from low Earth orbit while accelerating work on a heavy-lift launcher and crew capsule to support manned missions to deep space.

The bill, which authorizes NASA funding levels through 2013, also would add one more mission to the space shuttle manifest and support the international space station through at least 2020.

“NASA is an agency in transition. We’ve had to take a clear, hard look at what we want from our space agency in the years and decades to come,” Sen. Jay Rockefeller (D-W.Va.), who chairs the committee, said in a statement. “I’ve made my views on this matter very clear: NASA’s role cannot stay static. It must innovate and move in a new direction.”

An official with the administration of U.S. President Barack Obama said the bill backs key aspects of the $19 billion NASA spending plan Obama sent to Congress in February, including a top-line funding increase of $6 billion over five years, extending the space station through 2020 and terminating the Constellation program, under which the agency is developing the Ares rockets and Orion crew capsule to replace the space shuttle and take astronauts to the Moon.

“While we are still in the process of reviewing the details of the draft, the bill appears to contain the critical elements necessary for achieving the President’s vision for NASA and represents an important first step towards helping us achieve the key goals the President has laid out,” the administration official said in a July 15 statement. “We look forward to continuing to work with Congress to help advance an ambitious and achievable space program — one that helps us blaze a new trail of innovation and discovery.”

Sen. Bill Nelson (D-Fla.), who chairs the Senate Commerce science and space subcommittee and is largely responsible for shaping the bill, said it leverages the roughly $10 billion NASA has spent on Constellation along with decades of investment in the space shuttle program.

In remarks following the July 15 markup of the bill, Nelson said Obama’s budget rollout in February “gave the perception that he was killing the manned spaceflight program by the use of the word ‘canceling’ [with respect to] the Constellation program.” Nelson said if the administration had instead proposed restructuring the program, “it would have had a whole different atmosphere, but what was done was done.”

The bill would preclude any NASA procurement of commercial astronaut taxi services until 2012, and calls for studies to ensure “effective oversight” of the initiative, according to a bill summary issued by Nelson. Reliance on commercial crew taxi services to ferry crews to and from the space station is a key element of the White House plan.

The legislation also puts a heavy-lift rocket on a more aggressive schedule than Obama’s plan, initiating work in 2011 on a vehicle based on space shuttle and Constellation technologies that would be capable of delivering at least 130 metric tons to orbit, Nelson said.

“The committee cannot tell NASA how to design a rocket, but we can give policy direction to the executive branch of government and we’ve done that in the bill,” he said.

Obama in April directed NASA to settle on a heavy-lift rocket design no later than 2015.

“On a heavy lift rocket, this bill moves even farther from the Constellation program to accelerate heavy-lift development further (originally not set to begin until 2018),” the administration official said in the statement. “The President had already proposed building the heavy lift rocket sooner than under Constellation, this will further accelerate it so that we could begin manned flights in the early 2020s.”

The bill also calls for a deep space exploration crew capsule based on the work done to date on Orion to be ready for operations by the end of 2016.

During the markup, Nelson’s bill drew praise from both sides of the aisle, though a few members said more work lies ahead. Sen. Barbara Boxer (D-Calif.) said she was pleased to see the committee adopt an amendment she introduced during the hearing to increase funding for exploration technology development and robotic precursor missions, but added that more could be done to foster development of commercial cargo and crew capabilities.

“As we move to the floor I’m going to be teaming up with some colleagues who would like to see a little more depth in the commercial side,” she said during the markup. “We think this is a great area and we know the committee worked hard to find that balance, but we’d like to work a little more.”

In a statement following the hearing, Sen. Barbara Mikulski (D-Md.), who chairs the Senate Appropriations subcommittee responsible for NASA spending, characterized the authorization bill as “a solid compromise” and commended Nelson for “busting us out of the ‘stagnant quo’ for the space program.”

Mikulski’s subcommittee plans to mark up NASA appropriations legislation the week of July 19.