From: U.S. Senate Committee on Commerce, Science, and Transportation
Posted: Wednesday, September 3, 2003
Given at a Full Committee Hearing:
Columbia Accident Investigation Board (CAIB) Report on Shuttle Tragedy -- LIVE on C-SPAN 3
Wednesday, September 3 2003 - 9:30 AM - SR- 253
The Testimony of Admiral Harold Gehman, USN (Retired) Chairman, Columbia Accident Investigation Board
Good Morning Mr. Chairman, Senator Hollings, distinguished Members of the Committee.
I know members of this Committee feel as we on the Board do: that the price this Nation paid on February 1, 2003 was so dear, it demands we do our part to ensure an accident like this never happens again.
It is an honor to appear today before the Committee on Commerce, Science and Transportation. I thank you for inviting me to pay tribute to the legacy of Rick Husband, Willy McCool, Mike Anderson, Dave Brown, K.C. Chawla, Laurel Clark, and Ilan Ramon in presenting the findings of the investigation into the tragic loss of the Space Shuttle Columbia.
Before I begin, I would like to commend the efforts of my 12 fellow board members, 120 investigation staff members, 400 NASA engineers, and more than 25,000 debris searchers who have contributed immensely to the investigation.
Today I will provide the Committee with the final conclusions of the board with respect to the following three areas: · The physical cause of the accident · The organizational characteristics of NASA that contributed to the accident · Recommendations the Board has made in regards to the Space Shuttle Program
I. Physical Cause
The Board has determined that 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. The breach was initiated by a piece of insulating foam that separated from the left bipod ramp of the External Tank and struck the wing in the vicinity of the lower half of Reinforced Carbon-Carbon (RCC) panel 8 at 81.9 seconds after launch. During entry, this breach in the Thermal Protection System allowed superheated air to penetrate through the leading-edge insulation and progressively melt the aluminum structure of the left wing, resulting in a weakening of the structure until increasing aerodynamic forces caused loss of control, failure of the wing, and breakup of the orbiter.
Entry data demonstrated that the flaw in the left wing was extant prior to entry. The flight events are well documented, and establish that progressive destruction occurred as the orbiter entered the atmosphere. Superheated air damaged the structure of the wing first, leading to the abnormal aerodynamic forces that caused the eventual breakup. Once the orbiter began entry, there was no possibility of recovery. The Board reached this conclusion after extensive analysis of five lines of evidence: · The aerodynamic scenario · The thermodynamic scenario · The detailed system timeline from telemetry and recovered on-board recorder · The videographic and photographic scenario · Debris reconstruction and forensics
Additionally, the Board conducted foam impact tests in order to determine that this potential cause was indeed plausible. The tests proved this, and much more. The tests demonstrated that External Tank foam shed during launch could create considerable damage to the RCC panels and the tests also added to the body of knowledge regarding RCC strength. The foam impact testing ends for all time the common belief within NASA that foam strikes are just a flight turnaround issue, and also serves as a dramatic stimulus to change some people's attitudes about what we really “know.” Furthermore, it demonstrates the Board's finding that the characterization of the Space Shuttle as operational rather than experimental was flawed. The direct result of this mindset was the lack of testing on such matters as the cause of foam shedding, the force of foam projectiles, and the strength of the RCC panels to withstand such debris strikes.
II. Organizational Causes Mr. Chairman, the Board believes very strongly that complex systems almost always fail in complex ways. Most accident investigations fail to dig deeply enough into the causes beyond identifying the actual physical cause of the accident; for example, the part that failed and the person in the chain of command responsible for that failure. While this ensures that the failed part receives due attention and most likely will not fail again, such a narrow definition of causation usually does not lead to the fixes that prevent future accidents. Our investigation into the loss of the Columbia was designed to get to the heart of the accident, and reveal the characteristics of NASA that allowed the accident to occur. As everyone knows, NASA is an outstanding organization, with highly skilled and motivated people and a long history of amazing accomplishments. However, there are long-standing management issues that led to the Columbia disaster.
The organizational causes of this accident are rooted in the Space Shuttle Program's history and culture, including the original compromises that were required to gain approval for the Shuttle Program, subsequent years of resource constraints, fluctuating priorities, schedule pressures, mischaracterization of the Shuttle as operational rather than developmental, and lack of an agreed upon national vision for human spaceflight.
Cultural traits and organizational practices detrimental to safety were allowed to develop, including: · Reliance on past success as a substitute for sound engineering practices (such as testing to understand why systems were not performing in accordance with requirements) · Organizational barriers that prevented effective communication of critical safety information and stifled professional differences of opinion · Lack of integrated management across program elements · The evolution of an informal chain of command and decision-making processes that operated outside the organization's rules
The Board believes that these factors are just as much to blame as the foam. We began an analysis of how high reliability organizations handle risky enterprises, creating a template for us to use to examine management and culture at the Space Shuttle Program. The Board has concluded that the Space Shuttle Program does not have the characteristics of a high reliability organization. Furthermore, history and previous studies demonstrate that NASA, as a whole, does not “learn” well.
The results of our very intrusive investigation into the Space Shuttle Program demonstrate clearly that gradually and over a period of many years, the original system of checks and balances has atrophied. Instead of using a system of checks and balances provided by independent engineering and safety organizations, the Shuttle Program placed all responsibility and authority for schedule, manifest, cost, budgeting, personnel assignments, technical specifications and the waivers to those specifications and safety in one office. That action created an office that could make programmatic trades to achieve whatever goals were set for it by a higher authority. For example, if meeting the schedule were priority number one, the program could trade safety upgrades against schedule. We find this to be an excellent system if one's goal is to know whom to blame if something goes wrong, but NOT an excellent system if one's goal is to maximize safety.
The Board does not believe that the Space Shuttle is inherently unsafe, and we were under no pressure to say that it was safe. However, there are things that must be done to make it more safe than it is and many of these things must be accomplished before return to flight. Furthermore, if the Shuttle is to continue flying past the next few years, there are even more safety requirements necessary. Our recommendations and observations also constitute an attempt to find items that might be dangers in the future.
There are three types of recommendations in the report. The 15 Short-Term recommendations outline the fixes needed for return to flight. The 14 Mid-Term recommendations refer to the needs for continuing to fly for the next three to 12 years. The Long-Term recommendations discuss the considerations that must be made for continuing to fly the Space Shuttle beyond 12 years, including recommendations for replacing the Shuttle.
In addition to the cultural and organizational considerations that NASA must address, there are several recommendations that stand out. One of these is the call for NASA to take an integrated approach to the issue of the danger posed by debris by combining steps to reduce debris creation in the first place, an overall toughening of the orbiter, both in the RCC components and the other parts of the Thermal Protection System, including the tiles, and developing a capability for on-orbit inspection and repair. The Board studied scores of other findings of significance with respect to how exactly to prevent the next accident. Among the numerous recommendations is the need for better engineering drawings, better safety and quality assurance programs, and improved documentation. Additionally, there are specific ways to improve the orbiter maintenance down period without sacrificing safety, as well as recommendations on what to look for on bolt fractures, holdpost anomalies, Solid Rocket Booster attach rings, test equipment and training needs.
Mr. Chairman, during my last testimony before this committee, I promised a final report that places this accident in context, rendering the complete picture of how the loss of the Columbia fits into the complicated mosaic of budget trends, the myriad previous external reviews of NASA and the Shuttle Program, the implementation of Rogers Commission recommendations, changing Administrations and changing priorities, previous declarations of estimates of risk, work force trends, management issues and several other factors. We have done this to the best of our ability and I believe we have succeeded.
It is our intent that this report be the basis for an important public policy debate that needs to follow. We must establish the Nation's vision for human space flight, and determine how willing we are to resource that vision. From these decisions will flow the debate on how urgent it is to replace the Shuttle and what the balance should be between robotic and human space flight, as well as many other pressing questions on the future of human space flight. Let the debate begin.
Thank you Mr. Chairman. This concludes my prepared remarks and I look forward to your questions.
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