In the aftermath of the Columbia shuttle disaster, lawmakers from both parties said yesterday the country must still pursue space exploration. But they suggested Congress would play a more aggressive oversight role in the months to come, as it assesses whether NASA shortchanged the shuttle's safety program.

Rep. Dana Rohrabacher (R-Calif.), who chairs the House Science subcommittee on space and aeronautics, said he and others have warned for more than a year that the shuttle system was aging but that the National Aeronautics and Space Administration had not developed a replacement.

"In the months ahead, we've got to make sure to hold hearings to get to the heart of the issue, to determine the fundamentals that are in play that caused this catastrophe to happen," Rohrabacher said. "Space has been on the back burner for the past 10 years."

Nearly a year ago, Richard Blomberg, the outgoing chairman of the Aerospace Safety Advisory Panel, testified before Rohrabacher's panel that in all his years of involvement, he had "never been as concerned for space shuttle safety as . . . right now."

In that hearing, both Rohrabacher and his Democratic counterpart, Rep. Bart Gordon (Tenn.), sounded an alarm about the shuttle program. They questioned why NASA was pouring money into other research programs when the space shuttles were being put under more strain.

Gordon said yesterday that Congress should follow the model for the Challenger investigation, in which NASA conducted an internal and external review and staffers had simultaneous access to the findings. On a broader level, he added, policymakers must look at other issues such as how to replace an aging NASA workforce and maintain the international space station.

"We have to determine: What do we have, and is it doing the job?" Gordon said.

With the demise of Columbia on Saturday, lawmakers are preparing to probe what went wrong. Sen. John McCain (R-Ariz.) said he would hold hearings with NASA Administrator Sean O'Keefe to glean more information about the doomed flight.

"Obviously, we have to get the facts and we have to make policy decisions," McCain said. "I'm not ready to make any recommendations yet."

Although lawmakers noted it was too early to draw conclusions -- Rep. David Joseph Weldon (R-Fla.) said the explosion "looks more like a freak accident rather than the ramification of policy decisions of the past 10 years" -- they said the incident may force the administration and Congress to reassess how money is being spent on space exploration.

"One clear way to honor the dead is to develop a straightforward strategy at NASA so every single dollar goes to safety and scientific exploration," said Sen. Ron Wyden (D-Ore.). "The bottom line is you've had one blue-ribbon committee after another address various kinds of problems."

Wyden, who chaired the Commerce subcommittee on science, technology and space last Congress, said NASA had looked at the issues of debris breaking off during a launch and damage to the heat-deflecting tiles, but "at this point, nobody's certain about any of these issues."

Jim Muncey, a former House Science Committee staffer who now works as a consultant for government contractors and private space companies, said that after the Challenger disaster, politicians focused on management problems at NASA. This time, he noted, it was the more complicated question of how to allocate resources.

"They would rob the shuttle program to pay for the space station," Muncey said.

While space station costs were rising, projects aimed at replacing the shuttles, such as X-33/VentureStar, never flew despite a $1 billion investment between 1996 and 2000.

Rohrabacher said that the United States had remained "dependent on the shuttle system for far too long" and that the Bush administration was right to pursue a smaller vehicle, known as the orbital space plane, that uses conventional rockets.

Despite the Columbia disaster, lawmakers from both parties said they were committed to funding future space travel. The program remains politically popular; Wyden noted that schoolchildren ask him about it wherever he goes.

"Space exploration is a mission the U.S. will not abandon," McCain said. "The question is, how do we do it more efficiently and safely?"

Sen. John McCain said the country will not abandon space exploration.Sen. Ron Wyden said NASA needs a strategy to ensure safety funding.