CAPE CANAVERAL, Fla. -- There's a slim chance no one will ever be able to determine the root cause of Columbia's break up over Texas, but the nation's top investigators into aviation mishaps and other disasters are hopeful that won't be the case.

Gathered Tuesday at the Johnson Space Center in Houston, the Columbia Accident Investigation Board (CAIB) appeared together before the news media to set the stage for their work over the next few months and to assure the nation they will remain free from any outside influence.

Appointed by NASA Administrator Sean O'Keefe in the hours following the Feb. 1 tragedy, the board's independence is expected to be a topic of some discussion Wednesday during a joint hearing on Capitol Hill.

"There is only one investigation going on and it is our investigation," said CAIB chairman Hal Gehman, a retired Navy admiral, who led the investigation into the 2000 terrorist bombing of the USS Cole.

Gehman introduced the distinguished panel of experts that will study NASA's worst space accident in 17 years, described the board's organization and operational philosophy and answered questions about the status of the investigation and his plans for releasing new information to the public.

"We are driven by two imperatives," Gehman said, promising to "get it right" by taking their time and being very meticulous, while at the same time ensuring the board's work moves along "as rapidly as we possibly can."

With that in mind, the board plans to travel to the Kennedy Space Center in Florida on Wednesday to tour the hangars and launch pads. Then on Thursday they'll move to the Marshal Space Flight Center in Alabama.

On their way back Texas this weekend, they'll stop at NASAs Michoud Assembly Facility near New Orleans, where the shuttle's external tanks are manufactured and shipped via barge to Florida.

Returning to Houston on Saturday, the board plans to set up shop with staff and offices located near the Johnson Space Center but not on space center property -- another nod to the board's desire to remain independent.

At that point the investigative work will continue in earnest, with the goal to determine the root cause of the loss of Columbia and crew, determine the best fix and recommend a course of action that will return NASA to flight.

The board plans to interview anyone within the space community they think can help with the investigation.

"We aren't out to find any guilty people or find any negligence or culpability," Gehman said. "But if you have a secretary in a potted plant outside your office, then you're fair game."

The original plan was for the work to take about 60 days, but Gehman said it could take a little longer. The presidential commission that looked into the 1986 Challenger disaster took about four months.

Board members said Tuesday they were confident enough data would be available from which to draw a fair and accurate conclusion.

"Our charter is to try to find the cause and to the extent we can drill down and ask enough questions of why, we're going to attempt to do that," Maj. Gen. Ken Hess, the Air Force's chief of safety and commander of the Air Force Safety Center at Kirtland Air Force Base, N.M., told the assembled media.

"But it is a probable outcome that we may not find the exact cause of this mishap," Hess warned. "But we will have to let the information speak for itself on the course of the investigation."

Based on past investigations of aircraft accidents, Hess said there are times when a report will say only "what we most likely think may have happened, but you can never prove it with all certainty."

Another board member, Rear Admiral Stephen Turcotte -- commander of the Naval Safety Center in Norfolk, Va. -- expressed confidence a probably cause would be found, but left the door open for the possibility that the exact cause of Columbia's loss wouldn't be identified.

"In any investigation you go in and the very first thing you do is make no assumptions, you make no judgments, and you suspect everything," Turcotte said.

"Looking at the complexity of this, it is huge. It is one of the biggest debris fields that I think any of us have ever seen. The complexity of the science and technology that goes into it, is huge. We're going to look at everything and we're going to narrow it down to the most probable cause, if not the cause," Turcotte said.

To that end, the board has divided itself into three "sub-boards," each dedicated to a certain area of NASA's shuttle program, Gehman said.

Material and Management will look at the work that goes on to prepare shuttles between flights, the manufacturing of flight hardware, quality control issues related to the equipment and the way the different management boards and committees work with each other and share information.

Operations will look at the way astronauts are trained for and conduct their missions, as well as the way missions are planned, people are certified for their work in space or on the flight control teams and other tasks related actually carrying out human spaceflight.

Technical and Engineering will look at the telemetry sent down from Columbia, the shuttle's debris, the types of tests that should be done with any debris all that will be required to do the full technical analysis of the accident.

"There's a ton of work to be done," Gehman said, noting that he is interested in expanding the board's membership to include experts in fields of science, engineering and physics. At the very least, some specialists may be hired by the board to assist in these areas, he said.

Gehman also described the formation of an Independent Analysis Team that would further establish distance between the board and the space agency, helping the board analyze engineering data or conduct tests to confirm any NASA work.

"It's not that we don't believe the NASA data," Gehman said. "It's just that in order that the report be truly independent, and that the conclusions be based on good solid analytical work, both inside NASA and outside NASA, this team will advise us on when we come across one of those junctures in the road."