CONCLUSIONS

CONCLUSIONS

¶In execution of its oversight responsibilities, the Committee on Science and Technology has conducted a thorough investigation of the Challenger accident. Although the Committee's concern and evaluation in this report are related specifically to the safe and ef- fective functioning of NASA's Space Shuttle program, it should be understood that our larger objective and greater responsibility are to insure that NASA, as the Nation's civilian space agency, main- tains organizational and programmatic excellence across the board.

¶What we as a Committee, NASA as an agency, and the Nation as a whole, also must realize is that the lessons learned by the Chal- lenger accident are universally applicable, not just for NASA but for governments, and for society. We hope that this report will serve this much larger purpose.

¶The Committee's investigation included: ten formal hearings in- volving 60 witnesses; an extensive review of the report of the Rogers Commission along with its voluminous supporting appendi- ces and related reports by the investigation panels at NASA, as well as numerous briefings and interviews with NASA officials, contractor personnel, outside experts, and other interested parties.

¶From the outset, the focus of the Committee's investigation has been on understanding each of the following:

What was the cause, or causes, of the Challenger acci- dent? Are there other inherent hardware or management-re- lated deficiencies that could cause additional accidents in the future? What must be done to correct all of these problems so that the Space Shuttle can be safely returned to flight status?

¶The Committee found that NASA's drive to achieve a launch schedule of 24 flights per year created pressure throughout the agency that directly contributed to unsafe launch operations. The Committee believes that the pressure to push for an unrealistic number of flights continues to exist in some sectors of NASA and jeopardizes the promotion of a "safety first" attitude throughout the Shuttle program.

¶The Committee, the Congress, and the Administration have played a contributing role in creating this pressure. Congressional and Administration policy and posture indicated that a reliable flight schedule with internationally competitive flight costs was a near-term objective.

¶Pressures within NASA to attempt to evolve from an R&D agency into a quasicompetitive business operation caused a realign- ment of priorities in the direction of productivity at the cost of safety.

¶(3)

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¶NASA management and the Congress must remember the les- sons learned from the Challenger accident and never again set un- reasonable goals which stress the system beyond its safe function- ing.

¶The Committee commends the work of the Rogers Commission and its supporting panels at NASA. Their investigation and the re- ports that document their efforts are very broad in scope and ex- ceptionally detailed considering the time that was available to ac- complish their task.

¶As a rule, the Committee agrees with the findings reached by the Rogers Commission. However, there are areas where the Commit- tee either disagrees with a Rogers Commission finding or with the relative importance that the Rogers Commission attached to that finding.

¶Like the Rogers Commission, the Committee concluded that the Challenger accident was caused by a failure in the aft field joint on the right-hand Solid Rocket Motor. Additionally, we agree with the Rogers Commission that this tragic accident was not caused by the Orbiter, the Space Shuttle Main Engines, the External Tank, the onboard payloads, the ground support equipment, or the other ele- ments of the Solid Rocket Boosters. We also agree that the failure of the joint was due to a faulty design, and that neither NASA nor Thiokol fully understood the operation of the joint prior to the acci- dent. Further, the joint test and certification programs were inad- equate, and neither NASA nor Thiokol responded adequately to available warning signs that the joint design was defective.

¶In concurrence with the Rogers Commission, the Committee con- firms that the safety, reliability, and quality assurance programs within NASA were grossly inadequate, but in addition recommends that NASA review its risk management activities to define a com- plete risk management program. The Committee also agrees that a thorough review must be conducted on all Criticality 1 and 1R items and hazard analyses; a study should be conducted on how to provide Space Shuttle crews with a means of escape during con- trolled gliding flight; and NASA's Shuttle management structure, safety organization, communications procedures, and maintenance policies should be carefully scrutinized and improved.

¶In other areas, the Committee reached somewhat different con- clusions than the Rogers Commission:

The Rogers Commission concluded that NASA's decision- making process was flawed. The Committee does agree that the Marshall Space Flight Center should have passed along to higher management levels the temperature con- cerns that Thiokol engineers raised the night before the launch of Mission 51-L. However, the Committee feels that the underlying problem which led to the Challenger acci- dent was not poor communication or inadequate proce- dures as implied by the Rogers Commission conclusion.' Rather, the fundamental problem was poor technical deci- sion-making over a period of several years by top NASA

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and contractor personnel, who failed to act decisively to solve the increasingly serious anomalies in the Solid Rocket Booster joints. Information on the flaws in the joint design and on the problems encountered in missions prior to 51-L was widely available and had been presented to all levels of Shuttle management. Despite the presence of significant amounts of information and the occurrence of at least one detailed briefing at Headquarters on the difficulties with the 0- rings, the NASA and Thiokol technical managers failed to understand or fully accept the seriousness of the problem. There was no sense of urgency on their part to correct the design flaws in the SRB. No one suggested grounding the fleet, nor did NASA embark on a concerted effort to remedy the deficiencies in O-ring performance. Rather, NASA chose to continue to fly with a flawed design and to follow a measured, 27-month, corrective program. The Committee has more concerns than those expressed by the Rogers Commission about the relative safety of the Space Shuttle Main Engine. We are impressed by the so- phistication and performance of the Main Engine, but are concerned that it may have inadequate safety margins to ensure continued safe operation. The Committee is also concerned by the presence of persistent operating prob- lems with the engine (e.g., cracked turbine blades and de- fective hydraulic actuators and temperature sensors), and believes that NASA should give serious consideration to not allowing the Main Engine to be operated (except in emergency situations) at a thrust level greater than the standard 104 percent. On the other hand, should NASA de- termine that a higher engine thrust setting is needed for programmatic reasons, the Committee believes that the space agency should take whatever actions are required to ensure that adequate operating margins are present to maintain safety. The Committee has gone beyond the Rogers Commission in recommending a new system specification to overcome the inadequacies of the landing gear, tire, wheel, brake and nose wheel steering systems. The Committee also con- cluded that orbiter landings appear to be high risk even under ideal conditions, which seldom occur. The Rogers Commission stated that "there appears to be a departure from the philosophy of the 1960s and 1970s re- lating to the use of astronauts in management positions."2 In contrast, after taking testimony from several former and current astronauts, the Committee could find no evi- dence that astronauts are denied the opportunity to enter management if they so choose. On the other hand, prior to the STS 51-L accident, astronauts were not encouraged to enter management.

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¶In still other areas, the Committee has raised concerns that do not appear to have been addressed sufficiently by the Rogers Com- mission. We are concerned that:

There are numerous other recurrent hardware problems that are either not fully understood by NASA or have not been corrected. The existing internal communication system is dissemi- nating too much information, often with little or no dis- crimination in its importance. Accordingly, recipients have difficulty "separating the wheat from the chaff." Existing contract incentives used by NASA do not ade- quately address or promote safety and quality concerns- most emphasis is placed on meeting cost and schedule re- quirements. NASA does not yet understand how or why the deficien- cies in Solid Rocket Motor testing and certification went undetected in spite of the very comprehensive processes and procedures used by the agency to conduct and oversee these activities. The Committee is concerned that without such an understanding, NASA will not be able to protect against a similar breakdown in its system of checks and balances in the future. The Committee has concerns regarding the safety of the Filament Wound Case Solid Rocket Booster now under de- velopment by NASA, and recommends that the agency consider moving the heaviest Space Shuttle payloads to ex- pendable launch vehicles so that there will be no need to use Filament Wound Case Boosters. The Committee is not assured that NASA has adequate technical and scientific expertise to conduct the Space Shuttle program properly. NASA has suffered staffing re- ductions in key areas over several years. Moreover, it loses a significant number of technical/scientific personnel due to an imbalance between the government salary schedule and that of the private sector. The salary structure also in- hibits NASA's ability to recruit top technical talent to re- place its losses. The record is not sufficient to warrant a formal finding on this matter. However, the Committee in- tends to conduct an in-depth review of NASA technical ability in the next Congress.

¶On July 14, 1986, NASA submitted to the President a report on what actions the space agency plans to take in response to the rec- ommendations of the Rogers Commission. The Committee believes that the plans contained in this report are a step in the right direc- tion. When fully implemented, these plans should substantially im- prove the safety of Space Shuttle flight operations. The Committee also endorses NASAs decision to move the proposed date for the next Space Shuttle launch beyond June 1987. This is a realistic and responsible decision that has removed some unnecessary pressure from the government and contractor personnel who must ensure that all hardware will be in readiness to reinstitute safe flight op- erations.

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¶Throughout the remainder of this report, the Committee address- es dozens of specific issues that relate to the Challenger accident. The Committee makes many recommendations for actions to be taken on the part of NASA to correct the problems that we have identified. The Committee directs NASA to report back to us by February 15, 1987, on how it is responding to each recommendation contained in this report.

¶In closing, the Committee would like to state that it continues to believe in and remains committed to a vigorous civilian space pro- gram. The Committee also continues to believe that the Space Shuttle is a critically important element of that program. The Committee's purpose, as NASA's primary overseer in the House, must be to monitor, understand, and help correct where necessary the patterns in NASA which lead to weakened and ineffective oper- ation.

¶We are at a watershed in NASA's history and the Nation's space program. NASA's 28-year existence represents its infancy. We must use the knowledge and experience from this time to insure a strong future for NASA and the US. space program throughout the 21st century.

¶This Committee has long been proud of the many awe-inspiring achievements of NASA and understands the importance of NASA's programs to the future well-being of this country. We as a Commit- tee have perhaps exhibited the human inclination to accept the successful completion of a flight or event as an indication of the overall strength of all aspects of its planning and execution. Per- haps it is arrogant to dissect and interrogate relentlessly projects and programs that bring home repeated A's €or achievement and accomplishment. However, all of us-NASA, the Committee, the Congress and the Nation-have learned from the Challenger trage- dy that it is wisdom to do so, and it is a reflection of respect for the human fallibility that we all possess.

¶We have no doubt that through the hard work and dedication of the men and women at NASA and its supporting contractors, the Space Shuttle will be safely returned to flight status-and will once again continue to impress people around the world with its many important accomplishments.

¶As has been said many times since the January 28th tragedy, space flight is a high risk undertaking. The Cwnmittee accepts this fact and applauds those men and women who, in spite of this risk, have chosen manned space flight as a career. Though we grieve at the loss of the Challenger crew, we do not believe that their sacri- fice was in vain. They would not want us to stop reaching into the unknown. Instead, they would want us to learn from our mistakes, correct any problems that have been identified, and then once again reach out to expand the boundaries of our experience in living and working in outer space.

111. COMPILATION OF ISSUES, FINDINGS, AND

RECOMMENDATIONS

¶This compilation is taken from the body of the report. In order to facilitate the reader's ability to refer to specific sections within the report, the outline in the following compilation corresponds to the Table of Contents and the body of this report:

THEACCIDENT

INTRODUCTION

¶Discussion Only

SOLID ROCKET MOTORS

History Issue

¶Was there sufficient time to correct the problems with the Solid Rocket Motor? Findings

1. Problems with the joints which connect the Solid Rocket Motor casings were recognized for many years. While attempts were made to correct these problems, the measures taken were in- sufficient to provide a reliable joint.

2. The joint seal problem was recognized by engineers in both NASA and Morton Thiokol in sufficient time to have been correct- ed by redesigning and manufacturing new joints before the acci- dent on January 28, 1986. Meeting flight schedules and cutting cost were given a higher priority than flight safety.

Summary of Casing Joint Design

¶Issue

¶Why did the aft field joint between the steel containers that hold the Solid Rocket Motor propellant fail to contain the burning gases of the propellant during lift-off and flight operations? Findings

1. The design of the field joint was unsatisfactory and could not reliably contain the burning propellant gases under the range of operating conditions to be expected during the lift-off and flight phases.

2. The O-ring materials and putty used in the design of the joint were unsatisfactory as used on the Shuttle, particularly during the winter months. Furthermore, neither NASA nor its contractor, Morton Thiokol, can adequately control the quality or consistency of these kinds of materials, which are made from recipes known

¶(9)

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¶only by the manufacturer and which can be changed without certi- fication and approval. Recommendations

1. NASA should write and issue a new and more accurate per- formance specification which would cover the full range of thermal and structural requirements for the Solid Rocket Motors, with an adequate factor of safety for unusually low temperatures.

The Committee concurs with the Rogers Commission Report

¶Recommendations on new joint design, but believes it is more ap- propriate to be more explicit in identifying the weaknesses in the joint design that need correction.

3. The field joints of the Solid Rocket Motors should be rede- signed to account for the following features while providing a sig- nificant factor of safety:

a. Movement in the joint, b. Proper spacing between tang and clevis, c. Seals made to withstand high and low temperatures under all dynamic thermal and structural loadings, d. Adequate sealing without the use of putty, e. Protection against insulation debonding and propellant cracking.

Testing and Certification

¶Discussion Only

Manufacturing Discussion Only

Stacking Operations

¶Issue

¶Was there any damage to the casing joints or contamination that occurred during the stacking operations when the Shuttle was as- sembled in the Vehicle Assembly Building (VAB) that could have contributed to the failure? Finding

¶There was no evidence of joint contamination, fracture or other damage from foreign objects or due to casing ovality that contribut- ed to the joint failure. Although certain problems occurred during stacking and the procedures were violated once, there was no evi- dence that these events contributed to the Flight 51-L accident.

Summary of Launch Operations

¶Issue 1

¶How was the decision to launch STS 51-L arrived at and why was it wrong? Findings

1. The Flight Readiness Review for STS 51-L was conducted in accordance with established procedure.

2. The decision to launch STS 51-L was based on a faulty engi- neering analysis of the SRM field joint seal behavior.

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3. Compounding this erroneous analysis were serious ongoing weaknesses in the Shuttle Safety, Reliability and Quality Assur- ance Program which had failed to exercise control over the prob- lem tracking systems, had not critiqued the engineering analysis advanced as an explanation of the SRM seal problem, and did not provide the independent perspective required by senior NASA managers at Flight Readiness Reviews.

4. The initial response of Marshall managers to the attempts of Thiokol engineers to raise the issue of temperature effects on the SRM seals caused Thiokol management to discount proper techni- cal concerns and engineering judgment in their recommendation to launch.

The Director of Marshall's Shuttle Projects Office may have

¶violated NASA's Flight Readiness Review policy directive by failing to report the results of the January 27th teleconference to the As- sociate Administrator for Space Flight.

6. The decision of the STS Program Manager to launch despite the uncertainty represented by ice on the Fixed Service Structure was not a prudent effort to mitigate avoidable risks to the Shuttle.

7. The Launch Director failed to place safety paramount in eval- uating the launch readiness of STS 51-L. 8. No launch should have been permitted until ice was cleared from the platform leading to the pad escape system.

8. Ice Team personnel and Rockwell contractors properly con- veyed their inability to predict the post-ignition behavior of ice.

9. Post-flight analysis indicates that ice did not exhibit the be- havior predicted by analysis, and that ice traversed a distance suf- ficient to strike the Shuttle during liftoff.

10. Failure to enforce a clear requirement for definite readiness statements contributed to failures in communication between NASA and its contractors during launch preparations. Issue 2

¶Should firing room personnel be allowed to waive launch commit criteria or equipment redlines during a launch countdown without a well-developed technical reason for doing so? Finding

¶NASA's management waived its own launch commit criteria on January 28, 1986, without a valid technical reason for doing so.

Retrieval, Transportation and Refurbishment

¶Issue

¶Were the motor casings used on STS 51-L damaged as a result of the retrieval, transportation and refurbishment operations follow- ing previous launches? Finding

¶There was no evidence of damage to the casings or joint due to prior use or preparation for reuse.

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EXTERNAL TANK

¶Issue

¶The External Tank was obviously involved in the accident. Was that involvement a cause or an effect? Findings

1. The Committee adopts the "Finding" of the Rogers Commis- sion that: "A review of the External Tank's construction records, acceptance testing, prelaunch and flight data and recovered hard- ware, does not support anything relating to the External Tank which caused or contributed to the cause of the accident."

2. The External Tank ruptured under the forces of a failed Solid Rocket Booster motor. These forces were far outside of any possible design considerations that could have been applied to the External Tank.

CREW SURVIVAL

¶Issue

¶Was the accident of STS 51-L on January 28, 1986, survivable? Finding

¶In the case of the tragic loss of the Space Shuttle Challenger and her crew on January 28, 1986, the Committee is convinced that the accident was not survivable.

SABOTAGE

¶Issue

¶Could the accident have been caused by sabotage, terrorism, or foreign covert action? Finding

¶The Committee is convinced that there is no evidence to support sabotage, terrorism or foreign covert action in the loss of the Chal- lenger.

ADDITIONAL AVENUES OF INVESTIGATION

¶Issue

¶Could the accident have been caused by some failure other than failure of the joint between the casings? Finding

¶As of September 15, 1986, the Committee has not found any cred- ible evidence to support any caiise of the Challenger accident, other than the failure of the aft casings joint in the right-hand Solid Rocket Booster. Nor has there been any substantial evidence of a secondary or parallel failure on Flight 51-L.

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DISCUSSION ISSUES OF CRITICAL

TECHNICAL ISSUES