While Saturday's crash of the Columbia space shuttle was undoubtedly a tragedy, U.S. leaders said it in no way will slow the advancements being made in space exploration and science.

However, questions are swirling over how NASA is going to get over the latest disaster in its shuttle program.

In his address to the nation Saturday, President Bush said the space shuttle program will continue despite Saturday's catastrophe, in which seven astronauts perished after the shuttle split into pieces only 16 minutes before landing.

"Mankind is led into the darkness beyond our world by the inspiration of discovery and the longing to understand. Our journey into space will go on," Bush said.

"Space exploration is a dangerous endeavor, and each space flight is fraught with risk," said House Speaker Dennis Hastert, R-Ill. "But the knowledge that we gain from these missions is invaluable."

"As the most fitting tribute to their courageous service and sacrifice, let us recommit ourselves to the defining dream that dominated their lives: a bold vision for America in space," House Majority Leader Tom DeLay of Texas said.

NASA officials agree that they will continue their mission.

"As difficult as this situation is, we are moving forward," Ron Dittemore, the shuttle program manager at NASA, said Saturday. "We're going to fix this problem. We're going to get back on the launch pad. We're going to launch shuttles again once we can."

Much like what happened after the Challenger exploded 73 seconds after lift off in 1986, NASA pledged to get a firmer grip on its program's vulnerabilities.

But what needs to be done is subject to differing opinions. First of all, Congress will have to review NASA's funding needs and prove it has the political will to meet them.

"NASA, the administration and Congress have faced tough choices in regard to funding," said Sen. Mike DeWine, R-Ohio, who is on the Senate Appropriations Committee. "There has never been enough money to do all the things we want to do in space. But that was true before this disaster and will be true after this disaster."

Sen. Kay Bailey Hutchison, R-Texas, chairwoman of the Science, Technology and Space Subcommittee of the Senate Commerce Committee, said she will hold hearings to discuss what's in store for NASA and its budget. Prior to Saturday's tragedy, Hutchison's panel already had scheduled a hearing Tuesday to examine recommendations for increased government funding for aerospace research.

Since the Challenger explosion in 1986, NASA has been rife with budget cuts, the loss of skilled personnel and pressure to perform more missions in shorter periods of time.

After Challenger exploded, NASA's shuttle program came to a screeching halt while the Rogers Commission, appointed to investigate the Challenger accident, reviewed the agency's structure. Nearly two years later, NASA got off the ground once more when it completed technical changes and implemented stricter quality control and safety regulations recommended by the commission.

The agency also adopted a more relaxed shuttle launch schedule, settling on an average of eight launches per year.

But NASA officials continued to be confronted by safety and mission concerns. In 1995, a NASA-sponsored study urged the agency to consolidate contracts. Maintenance requirements were relaxed to lessen the time between flights and the 2,800-member workforce was to be cut in half by the year 2000, leading many to worry that safety would suffer. Attrition and lay-offs soon followed.

Sen. Kit Bond, R-Mo., told Fox News on Saturday that NASA's aerospace safety team asked Congress to add an additional $207 million to last year's $15 billion budget for safety upgrades, which Congress agreed to appropriate.

"Shuttle safety is a vitally important part of their mission," Bond said. "It has to be at the top of their list."

But Sen. Bill Nelson, D-Fla., said safety upgrades have been delayed.

"Safety has got to be the number one concern," Nelson said, declining to suggest that delays contributed to Saturday's accident.

Aerospace experts say money and staffing are not the sole problems NASA faces. The agency also needs to change its philosophical underpinnings.

The United States should "take a hard look at NASA's future, in regards to new technologies and more modern systems," said Alan Ladwig, a former NASA administrator of policy and planning.

In the 1990s, NASA turned over day-to-day management of shuttle operations to a private contractor, Houston-based United Space Alliance, a joint venture of Rockwell International and Lockheed Martin. The move prompted many complaints from NASA employees who asked for more government oversight of the agency.

But others say funding and oversight will not fix NASA's problems. Rather, a more effective strategy would be to create a smaller research lab to test various technologies, then to send the research out to the private sector to expand upon.

"Unless a new policy is put in place that encourages that creativity rather than, by implication, discourages it by saying NASA is the only entity empowered to do these sorts of things with competence, then we will never have practical access to orbit," said aerospace engineer and policy consultant Charles Lurio.

"What we need is the Model-T for space. We don't know who's going to invent that. What we need is research to enable that not to be stuck on a single track," he said.