The Senate Commerce Committee approved legislation June 23 prohibiting NASA from retiring the space shuttle orbiter until a new crew transport vehicle has flown.

The proposed restriction was included in a NASA authorization bill co-sponsored by senators from Florida and Texas, two states that stand to lose thousands of jobs — at least temporarily — if the U.S. space agency retires the shuttle before a replacement vehicle is ready to go into service.

Speaking in support of the bill, Sen. Kay Bailey Hutchison (R-Texas), the chairwoman of the Senate Commerce science and space subcommittee, said “the possibility of a gap in spaceflight must be eliminated if the U.S. wants to be a leader in space exploration.”

NASA Administrator Mike Griffin is adamant about retiring the shuttle in 2010 and has said he intends to accelerate development of the proposed Crew Exploration Vehicle (CEV) in order to minimize any gap in U.S. ability to put humans in space. NASA previously had planned to field the CEV in 2014. Although Griffin has said he wants the CEV to be ready before then, he has not made its availability a precondition for retiring the shuttle.

The Senate’s version of the NASA authorization bill, if signed into law as is, would change that.

Specifically the bill says, “In order to ensure continuous human access to space, the Administrator may not retire the Space Shuttle orbiter until a replacement human-rated spacecraft system has demonstrated that it can take humans into Earth orbit and return them safely.”

Hutchison’s co-sponsor on the legislation and her Democratic counterpart on the subcommittee, Sen. Bill Nelson ( Fla.), also spoke about the importance of avoiding a hiatus in NASA’s ability to put astronauts in space. But neither Hutchison nor Nelson highlighted during the Commerce Committee’s June 23 meeting the restrictions the bill would impose on shuttle retirement.

NASA declined to comment on the language. “We are closely watching the NASA authorization bill and we are looking forward to working with Congress,” said NASA spokesman Dean Acosta. “It would be inappropriate to talk about it until the process is complete.”

Lawmakers in the House of Representatives intend to introduce their own NASA authorization bill June 27. The House version of the bill, according to sources familiar with it, would not require NASA to keep flying the shuttle until the CEV is ready. The House and Senate must sort out any differences between their respective versions of a bill before it can become law.

Congressional sources said Hutchison and Nelson do not appear to be dead set on keeping the restrictions on shuttle retirement in the final bill. After the June 23 markup, Nelson told Space News he was open to negotiations. “Sure, we can massage it a bit,” he said.

Congress has sent NASA authorization bills to the White House for the president’s signature only twice since 1992. The last time was in 2000. But the House and Senate are moving with relative speed this year to pass a NASA authorization. Lawmakers pushing the legislation note that the U.S. Congress has yet to formally endorse the Vision for Space Exploration proposed by President George W. Bush in January 2004, although Congress has given the vision tacit endorsement by approving the space agency’s budget request last year.

The Senate bill, S.1281, strongly endorses NASA’s new exploration goal, which include returning astronauts to the Moon by 2020 in preparation for eventual trips to Mars and beyond, and authorizes moderate spending increases for NASA for each of the next five years. But the bill parts with NASA’s public positions on both shuttle retirement and on plans to eliminate international space station-based research that does not directly support the agency’s exploration goals.

The Senate bill would “restore and protect” such long proposed space station research activities such as molecular crystal growth, animal research, basic fluid physics and combustion research.

The bill also would designate the U.S. portion of the space station a national laboratory facility, a designation, Hutchison said, that would open up new funding possibilities for the station and take some pressure off the NASA budget.

The bill also nudges NASA to design a new crew transport system and heavy-lift launcher that makes use of existing space shuttle components such as the solid rocket boosters, external tank and main engines, as well as the shuttle program’s workforce, manufacturing facilities and launch infrastructure.

The so-called shuttle-derived approach has an ardent champion in Griffin, who has said on numerous occasions that route is the way to go for meeting U.S. heavy-lift launch needs for human expeditions to the Moon and beyond.

Other highlights of the bill include:

– Provisions requiring NASA to invest in in-situ resource utilization technologies and to establish simulated lunar outposts in remote U.S. locations to test out these technologies and train for Moon missions.

– Language directing NASA to “pursue aggressively” automated rendezvous and docking technologies needed for delivering cargo to the space station.

– Authorization for NASA to award cash prizes of up to $50 million to stimulate technical innovations.

– A section requiring the president to establish national aeronautics policy to guide U.S. aeronautics research programs through 2020.

The committee rejected an amendment offered by Sen. George Allen (R-Va.) to set minimum funding levels for aeronautics. Allen’s amendment would have required NASA to spend at least $919 million on aeronautics research in 2006 and $946 million in 2007.

The committee also voted down an amendment offered by Sen. John Sununu (R-N.H.) that would have set minimum funding levels for Earth-Sun s ystems projects and the Space Interferometry Mission, a proposed planet-finding spacecraft.

Brian Berger is editor in chief of and the SpaceNews magazine. He joined in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...