None of the above, however, was known at the time and, after extensive con. sideration was given to the possibilities of damage from a loose fill tube, it was decided to leave the oxygen shelf and oxygen tank #2 in the SM and to proceed with preparations for the launch of Apollo 13. In fact, following the special detanking, the oxygen tank #2 was in a hazardous condition whenever it contained oxygen and was electrically energized. This condition caused the Apollo 13 accident, which was nearly catastrophic. Only the outstanding performance on the part of the crew, Mission Control, and other members of the team which supported the operations, successfully returned the crew to earth.

In investigating the Apollo 13 accident, the Board attempted to identify those additional technical and management lessons which can be applied to help assure the success of future spaceflight missions. Several recommendations of this nature are included.

RECOMMENDATIONS

Before reading the Board's recommendations, I would like to point out that each Member of the Board concurs in each finding, determination, and recommendation.

The Board's recommendations are as follows:

1. The cryogenic oxygen storage system in the service module should be modified to:

a. Remove from contact with the oxygen all wiring, and the unsealed motors, which can potentially short circuit and ignite adjacent materials; or otherwise insure against a catastrophic electrically induced fire in the tank.

b. Minimize the use of Teflon, aluminum, and other relatively combustible materials in the presence of the oxygen and potential ignition

sources.

2. The modified cryogenic oxygen storage system should be subjected to a rigorous requalification program, including careful attention to potential operational problems.

3. The warning systems onboard the Apollo spacecraft and in the Mission Control Center should be carefully reviewed and modified where appropriate, with specific attention to the following:

a. Increasing the differential between master alarm trip levels and expected normal operating ranges to avoid unnecessary alarms.

b. Changing the caution and warning system logic to prevent an outof-limits alarm from blocking another alarm when a second quantity in the same subsystem goes out of limits.

c. Establishing a second level of limit sensing in Mission Control on critical quantities with a visual or audible alarm which cannot be easily overlooked.

d. Providing independent talkback indicators for each of the six fuel cell reactant valves plus a master alarm when any valve closes.

4. Consumables and emergency equipment in the LM and the CM should be reviewed to determine whether steps should be taken to enhance their potential for use in a "lifeboat" mode.

5. The Manned Spacecraft Center should complete the special tests and analyses now underway in order to understand more completely the details of the Apollo 13 accident. In addition, the lunar module power system anomalies should receive careful attention. Other NASA Centers should continue their support to MSC in the areas of analysis and test.

6. Whenever significant anomalies occur in critical subsystems during final preparation for launch, standard procedures should require a presentation of all prior anomalies on that particular piece of equipment, including those which have previously been corrected or explained. Furthermore, critical decisions involving the flightworthiness of subsystems should require the presence and full participation of an expert who is intimately familiar with the details of that subsystem.

7. NASA should conduct a thorough reexamination of all of its spacecraft, launch vehicle, and ground systems which contain high-density oxygen, or other strong oxidizers, to identify and evaluate potential combustion hazards in the light of information developed in this investigation.

8. NASA should conduct additional research on materials compatibility. ignition, and combustion in strong oxidizers at various g levels; and on the characteristics of supercritical fluids. Where appropriate, new NASA design standards should be developed.

9. The Manned Spacecraft Center should reassess all Apollo spacecraft subsystems, and the engineering organizations responsible for them at MSC and at its prime contractors, to insure adequate understanding and control of the engineering and manufacturing details of these subsystems at the subcontractor and vendor level. Where necessary, organizational elements should be strengthened and in-depth reviews conducted on selected subsystems with emphasis on soundness of design, quality of manufacturing, adequacy of test, and operational experience.

CONCLUSION

In concluding. I would stress two points.

The first is that in this statement I have attempted to summarize the Board's Report. This Report and its appendices are the result of more than seven weeks of intensive work by the Board, its Panels, and staff, supported by the NASA and contractor organizations. In the interest of time. I have not included many supporting findings and determinations which are set forth in the Report. The second point I wish to make is this:

The Apollo 13 accident, which aborted man's third mission to explore the surface of the moon, is a harsh reminder of the immense difficulty of this undertaking.

The total Apollo system of ground complexes, launch vehicle, and spacecraft constitutes the most ambitious and demanding engineering development ever undertaken by man. For these missions to succeed, both men and equipment must perform to near perfection. That this system has already resulted in two successful lunar surface explorations is a tribute to those men and women who conceived, designed, built, and flew it.

Perfection is not only difficult to achieve, but difficult to maintain. The imperfection in Apollo 13 constituted a near disaster, averted only by outstanding performance on the part of the crew and the ground control team which supported them.

The Board feels that the Apollo 13 accident holds important lessons which, when applied to future missions, will contribute to the safety and effectiveness of manned space flight.

Mr. Chairman, this concludes my prepared statement.

STATEMENT BY DR. PAINE

The CHAIRMAN. Dr. Paine, go ahead.

Dr. PAINE. Mr. Chairman, members of the committee, in our appearance before the committee on April 24, 1970, Apollo Program Director Dr. Rocco Petrone, Flight Director Glynn Lunney, and astronauts Jim Lovell and Jack Swigert reported to you our understanding as of that time of the events leading to the accident and the subsequent operations which brought the astronauts safely back to earth. At the same hearing, I reported to you the actions Dr. Low and I had taken to assure a prompt, thorough, and objective investigation of the accident. These included:

REVIEWS ACTIONS FOLLOWING ACCIDENT

(1) The establishment of the Apollo 13 Review Board, with Mr. Edgar M. Cortright, Director of the Langley Research Center, as Chairman.

(2) The instruction to NASA's Aerospace Safety Advisory Panel to review the procedures and findings of the Apollo 13 Review Board and to submit its independent report within 10 days of the Review Board's report, and

(3) The instruction to Dr. Dale Myers, NASA's Associate Administrator for Manned Space Flight, to provide necessary support to the Apollo 13 Review Board and to make recommendations, also with

in 10 days of the Review Board's report, on plans for eliminating the problems encountered in Apollo 13 in order to proceed with Apollo 14 and future manned space missions.

REVIEWS RESULTS OF ACTIONS

Today we are here to review with you the results of these actions and the resulting future program actions which Dr. Low and I am now taking to preclude a recurrence of such accidents and to move ahead with the Nation's manned space flight program. In sum

mary:

The report of the Apollo 13 Review Board was presented to us by Mr. Cortright on June 15 and made available to the committee on the same day. Dr. Low and I have now had an opportunity to study the report in detail and to review carefully its recommendations. In our view it is an excellent report based on a thorough and objective investigation and highly competent analysis. It clearly pinpoints the causes of the Apollo 13 accident and sets forth a comprehensive set of recommendations to guide our efforts to prevent the occurrence of similar accidents in the future.

The Aerospace Safety Advisory Panel submitted its report to NASA management at a meeting in Washington June 25, 1970. With your permission, Mr. Chairman, I would like to place its report which is in the form of a letter from its Chairman, Dr. Charles D. Harrington, in the record.

The CHAIRMAN. Without objection, that will be done.

(For the letter referred to see p. 56.)

Dr. PAINE. Dr. Harrington is here this morning to respond to any questions you may have. At this point I would like to read the key portions of his letter report summarizing the Safety Panel's appraisal of the job done by the Apollo 13 Review Board. He says:

The Panel found that the Board' procedures and scope of inquiry proved effective in their task. The Review Board has performed a thorough and technically competent analysis in the reconstruction of the factors contributing to the Apollo 13 abort. We found no evidence and no reason to doubt the technical validity of their determination and findings.

This independent evaluation provides substantial additional confidence to Dr. Low and to me that our favorable appraisal of the report is correct.

Dr. Myers, Dr. Petrone, and the Office of Manned Space Flight have also completed extensive experiments, tests, studies, reviews, redesign work and program rescheduling activities, and have presented recommendations on the required corrective measures and program adaptations. Last Thursday Dr. Low and I held an extensive review at which Dr. Myers, Dr. Petrone, Colonel McDivitt and other officials of the Apollo program discussed in detail the technical problems and alternatives with the senior officials of NASA. Also present were Mr. Cortright and members of the Review Board, Dr. Harrington and members of the Aerospace Safety Advisory Panel, Mr. William A. Anders, Executive Secretary of the National Aeronautics and Space Council, and the Directors of NASA's Manned Space Flight centers: Dr. Robert R. Gilruth, Dr. Kurt H. Debus, and Dr. Eberhard Rees. Based on the discussions at this review and at followup meetings ex

tending over the next 2 days, Dr. Myers has formally submitted to me with his endorsement the final recommendations of Dr. Petrone, the Apollo Program Director. These are embodied in Dr. Petrone's memorandum to me of June 27, 1970, which has been made available to the committee, and which I would like to place in this record, with your permission, Mr. Chairman.

The CHAIRMAN. Without objection; that will be done.

(For the memorandum referred to see p. 57.)

Dr. PAINE. On the basis of the reports and recommendations before us and detailed discussions with responsible and knowledgeable experts in NASA, Dr. Low and I have approved the following actions to implement the recommendations of the Apollo 13 Review Board and to carry out the steps recommended by Dr. Petrone and Dr. Myers to prepare for the Apollo 14 mission. In summary, these actions are:

APOLLO 14 POSTPONED TO EARLY 1971

First, the recommendations of the Apollo 13 Review Board will be implemented before the Apollo 14 mission is approved for launch. This will require postponing the launch date to no earlier than January 31, 1971. Command Service Module systems will be modified along the recommended lines to eliminate potential combustion hazards in high pressure oxygen of the type revealed by the Apollo 13 accident. Unsealed fan motors will be removed from the oxygen tanks and an additional oxygen tank added to the service module of Apollo 14. Electrical wiring within high pressure oxygen systems which might provide an ignition spark if damaged will be limited to stainless steel sheathed wires. Teflon, aluminum, and other potentially reactive materials in the presence of high pressure oxygen will be used as little as possible and kept away from possible ignition sources. For example, the quantity probe will be stainless steel instead of aluminum and the fuel cell oxygen supply valve which now has Teflon-insulated wires in high pressure oxygen will be redesigned to eliminate this hazard. Warning systems on board the spacecraft and at mission control will be modified consistent with the Board's recommendations to provide more immediate and visible warnings of system anomalies. A comprehensive review of spacecraft emergency equipment and procedures and use of command service modules and lunar modules in "lifeboat" modes is now underway at the Manned Spacecraft Center in Houston. Dr. Petrone will outline for you the specific actions we plan to take in response to the first six recommendations of the Board, and Dr. Myers will discuss his specific plans for critically reassessing all Apollo spacecraft subsystems in response to recommendation No. 9 of the Board.

NASA REVIEW OF APOLLO 13 REPORT

Secondly, the associate administrators in charge of the Offices of Space Science and Applications, Manned Space Flight, and Advanced Research and Technology, have been directed to review the Apollo 13 review board report to apply throughout NASA the lessons learned in their areas of responsibility. They have been instructed to take action with respect to recommendation No. 6 (concerning anomalies

in critical subsystems prior to flight), recommendation No. 7 (calling for a thorough reexamination of all spacecraft, launch vehicle and ground systems which contain strong oxidizers to evaluate potential hazards) and recommendation No. 9 (concerning the design, manufacture, test, and operation of spacecraft subsystems). I have requested a written report by August 25 on their assessment and the actions taken or proposed.

In addition, we will take steps to disseminate widely throughout the industry and the technical community the lessons of Apollo 13 to prevent recurrences in other areas. You might be interested to know in this connection that I have forwarded to Academician Keldysh of the Soviet Academy of Sciences a copy of the complete Apollo 13 Review Board report so that lessons which might be learned from our accident can be applied to prevent a similar hazard to Soviet cosmonauts.

Third, the Aerospace Safety Research and Data Institute (ASRDI) at the NASA Lewis Research Center has been directed to conduct additional research on materials compatibility, ignition, and combustion at various gravity levels, and on the characteristics of supercritical fluids, as recommended by the Apollo 13 Review Board. This will expand a review already begun by ASRDI on oxygen handling in aerospace programs. In this effort, the Lewis Research Center will be supported by other elements of the NASA organization. This research will be of direct long-term benefit to NASA in carrying out its future programs, and will help other sectors of the economy.

AEROSPACE SAFETY ADVISORY PANEL

Fourth, I have requested that the Aerospace Safety Advisory Panel conduct a review of the management processes utilized by NASA in implementing the recommendations of the Apollo 13 Review Board and report to me their views no later than the Apollo 14 flight readiness review. This will again give us the benefit of the panel's valuable independent insight when future decisions are made. I have also asked Mr. Cortright to reconvene the Apollo 13 Review Board later this year, as he suggested, to review the results of continuing tests to determine whether any modifications to the board's findings, determinations, or recommendations are necessary in light of additional evidence which may become available.

JANUARY LAUNCH OF APOLLO 14 POSSIBLE

The assessment of the Office of Manned Space Flight, in which Dr. Low and I concur, is that the reasonable time required for the design, fabrication, and qualification testing of the modifications to the Apollo system we have determined to be necessary, and for the other actions outlined above which must be taken before the next Apollo mission, will permit us to launch Apollo 14 to the Fra Mauro region of the moon at the January 31, 1971, launch opportunity. This will also move the planned launch date for Apollo 15 several months to July or August 1971, maintaining the approximate 6-month interval between launches on which our operations in the Apollo program are now based. However, we will not launch Apollo 14 or any other flight unless and until we are confident that we have done everything necessary to eliminate the conditions that caused or contributed