"There have been fits and starts of a national debate," said Senator Ernest F. Hollings of South Carolina, the ranking Democrat on the Commerce Committee, which has jurisdiction over NASA.

Mr. Hollings plans to introduce a bill on Wednesday to create a national space commission to oversee NASA's progress in fixing the hardware and the "broken safety culture" identified in the Columbia investigation, and to help set goals.

Senator Hollings's bill, which has six sponsors, all Democrats, joins a varied flock of measures on the House side, none likely to see major action this year.

"It's not commanding anywhere near the level of attention that the Challenger did," said a House staff aide who was on Capitol Hill at the time of that accident, in 1986.

The war in Iraq helps explain the difference, the aide added, but beyond that, "space is more humdrum now," even when astronauts die.

Sean O'Keefe, the NASA administrator, said in testimony last week that the Bush administration would produce a new plan for space, including a replacement vehicle for the shuttle, now more than 20 years old. He said Congress should wait until that plan is released, but he refused to predict how long that would take.

The leisurely pace contrasts with the push by the Columbia Accident Investigation Board to complete its work over the summer so members of Congress could digest the report during their recess and be ready for a vigorous debate when they returned.

The most prominent feature of the debate so far has been a skirmish between NASA and the chairman of the House Science Committee and the ranking Democrat on the panel. The two lawmakers, Representatives Sherwood Boehlert, Republican of New York, and Ralph M. Hall, Democrat of Texas, suggested that NASA hold off on development of an orbital space plane, a crew-transport vehicle that could replace the shuttle, until an "overall vision for the human spaceflight program" emerges.

Mr. Boehlert said at a hearing on Oct. 16 that NASA would be successful "only if it's pursuing a clear and broad national consensus with sustained and adequate funding," and he added, "That hasn't been the case in three decades."

Mr. O'Keefe, responding to the letter on the orbital space plane, argued that the project was still at a conceptual stage and should proceed.

Beyond establishing a commission to oversee NASA's progress, the Senate bill to be introduced on Wednesday seeks "to address broader questions about the goals and methods we use," with specific concern for public and private investment in spaceflight and use of it. In remarks prepared for delivery on the Senate floor on Wednesday, Mr. Hollings argues that while economics of spaceflight should not take precedence over safety, "we also know that, in the past, its cost has driven us down pathways that have not resulted in success."

On the House side, Representative Bart Gordon, Democrat of Tennessee, introduced a bill that would have future accidents investigated by a presidential commission independent of NASA. The Columbia Accident Investigation Board began under a charter written after the Challenger accident, with members selected according to positions they held in the Air Force, Federal Aviation Administration and other agencies.

Mr. Gordon's bill was approved by a subcommittee but has gone no further.

Mr. Hall, the ranking Democrat on the House Science Committee, introduced a bill on Oct. 1, with 24 sponsors, including 3 Republicans, that would have the National Academy of Sciences and the National Academy of Engineering assemble an oversight committee, as was done after the Challenger accident. NASA has generally opposed outside oversight.

Mr. Hall also introduced an amendment to an appropriations bill that would mandate a $15 million study of shuttle crew escape, to be performed by NASA. The House passed the bill, and it is now in a conference committee.

Representative Nick Lampson, Democrat of Texas, has introduced a measure that would require NASA to develop reusable spaceships that could sit for long periods balanced between the gravitational pull of Earth and the Sun or the Moon; ships that could reach an asteroid; and, ultimately, ones that could reach Mars. The bill has 24 sponsors but has not yet been taken up in committee.

Mr. Lampson said in a telephone interview that he was glad that Senator Hollings was focused on the problem, but he added, "We don't need a commission, we need a commitment for NASA."

"If the goals get set, we will re-energize the academic community, and the space industrial community," he said, predicting that missions to Mars would "do a great deal to move this country forward."

Mr. Hollings, in a separate interview, said, "I want to go to Mars, too, but unless you get the culture changed and fixed, we're not going anywhere."