The Columbia Accident Investigation Board, in a wide-ranging analysis of decades of NASA history, said the space agency's attitude toward safety is little improved since the 1986 Challenger disaster.
"The physical cause of the loss of Columbia and its crew was a breach in the Thermal Protection System on the leading edge of the left wing, caused by a piece of insulating foam," the report read. "The organizational causes of this accident are rooted in the space shuttle program's history and culture."
The report includes a list of challenges NASA must meet before the shuttle can fly again, reports CBS News Correspondent Bob Orr. "The board strongly believes that if these persistent, systemic flaws are not resolved, the scene is set for another accident," the report said.
At an afternoon news conference, NASA administrator Sean O'Keefe accepted the report's tough verdict.
"Our first step must be to accept the findings and comply with the recommendations," he said, acknowledging that the agency needs "to change in order to mitigate against succumbing to these failures."
Retired Navy Adm. Harold Gehman, Jr., chairman of the Columbia Accident Investigation Board, told CBS News Space Consultant William Harwood NASA has little choice but to comply.
"We think there's no room for any doubt whatsoever, the management system they have right now is not capable of safely operating the shuttle over
the long term. That's the bottom line," Gehman said.
Gehman told Harwood the space agency's management system is so dysfunctional it hardly mattered who was in charge.
"We believe very, very strongly that you could substitute almost
anybody in those positions and operate under the guidelines and rules
and precedents that were being used in NASA and they would make the
same errors," he said.
In a statement, President Bush thanked the board for a thorough review and recognized the courage of the seven astronauts who were lost.
"The next steps for NASA under Sean O'Keefe's leadership must be determined after a thorough review of the entire report, including its recommendations," the president said. "Our journey into space will go on. The work of the crew of the Columbia and the heroic explorers who traveled before them will continue."
In events leading up to the loss of Columbia, the report said, NASA mission managers fell into the habit of accepting as normal some flaws in the shuttle system and tended to ignore or not recognize that these problems could foreshadow catastrophe. This is an "echo" of some root causes of the Challenger accident, the board said.
During Columbia's last mission, NASA managers missed opportunities to evaluate possible damage to the craft's heat shield from a strike on the left wing by flying foam insulation.
When Columbia re-entered the atmosphere on Feb. 1, superheated air penetrated the wing and melted it from the inside, causing the spacecraft to break apart and scattering debris over parts of the states of Texas and Louisiana. Columbia's crew died within seconds after Mission Control lost signals from the shuttle.
"In four simple words, the foam did it," said G. Scott Hubbard, head of NASA's Ames Research Center.
Such insulation strikes had occurred on previous missions and the report said NASA managers had come to view them as an acceptable abnormality that posed no safety risk.
This attitude also contributed to the lack of interest in getting spy satellite photos of Columbia, images that might have identified the extent of damage on the shuttle, and led to incorrect conclusions.
But most of all, the report noted, there was "ineffective leadership" that "failed to fulfill the implicit contract to do whatever is possible to ensure the safety of the crew."
Management techniques in NASA, the report said, discouraged dissenting views on safety issues and ultimately created "blind spots" about the risk to the space shuttle of the foam insulation impact.
Throughout its history, the report found, "NASA has consistently struggled to achieve viable safety programs" but the agency effort "has fallen short of its mark."
Some blame in the report was shifted to Congress and the White House because for almost a decade NASA lived on a lean budget that actually lost 13 percent of its purchasing power from 1993 to 2002.
At the same time, NASA was under pressure to build the International Space Station. To cut costs, the agency reduced its staff and contractor work force from about 32,000 in 1991 to just over 19,000 in 1997.
As a result, "safety and support upgrades were delayed or deferred, and Shuttle infrastructure was allowed to deteriorate."
The board made 29 recommendations, including changes it said NASA must make to start flying again and long-range changes that will alter the space agency culture.
The directives include steps to prevent the insulation from shedding debris, and making the shuttle better able to withstand debris strikes and survive reentry if damage occurs.
Asked if the board recommended discipline of any NASA manager Gehman said, "The role of establishing judgments on personal performance is not one that we set out to do."
Gehman said he was sure NASA would pay close attention to the immediate fixes required for return to flight. "The board, however, is concerned that over a period of a year or two the natural tendency of all bureaucracies to morph and migrate away from that diligent attitude is a concern, because NASA has done it before," Gehman said.