The Apollo Spacecraft - A Chronology.

Part 2 (B)

Recovery, Spacecraft Redefinition, and First Manned Apollo Flight

May 1967

1967

May 1

MSC estimated the effect of the Apollo 204 fire on program costs for FY 1967 and 1968, in reply to April 26 instructions from NASA Apollo Program.

Manager Samuel C. Phillips. Estimates were:

Command and service modules $25 million
Lunar module $21 million
Other $35 million
Total $81 million

Further, the program extension resulting from the accident would require an additional budget allocation during FY 1969 and continuing through program runout. A May 4 message from MSC confirmed the information telephoned to Headquarters May 1.

The following ground rules had been used in estimating the cost impact:

All changes planned as of May 1 for the command and service modules and the lunar module were included.
Vehicle delivery dates were as of April 29. Guidance and navigation schedules were adjusted to support revised CSM and LM need dates.

TWXs, NASA Hq. to MSC, "Cost Impact of 204 Accident," April 26, 1967; MSC to NASA Hq., "Cost Impact of the 204 Accident," May 4, 1967.

May 1

The Space and Information Systems Division of North American Aviation, Inc., was renamed Space Division, effective May 1.

TWX, North American Aviation Space Div., Downey, Calif., to NASA Hq., MSFC, MSC, and KSC, "Redesignation of S&ID as Space Division," May 9, 1967.

May 1

George C. White, Jr., NASA OMSF Director of Apollo Reliability and Quality, told Apollo Program Director Samuel C. Phillips that an MSC presentation on April 29 had restored confidence in Apollo's future, but three areas caused him concern as possible compromises with crew safety and mission success in the interest of near-term schedule and cost considerations. They were:

Soldered joints in coolant system plumbing. Design of the joints was basically wrong; the insertion of the tubing into the sleeve was less than the tube diameter. Shear strength of the solder had to be depended upon for mechanical integrity against bending and vibration as well as for sealing. Insertion should be two to three times the diameter so that bending could be carried by the bearing of the tube in the sleeve, and the solder would only have to seal.
Wiring harnesses. Wiring in the Block II spacecraft had a number of problems, the real significance of which was difficult to evaluate. Numerous instances of damaged insulation (bare conductor) had been found and the repairs had, in turn, resulted in more damage. At least once, split insulation (bare conductor) had been found inside a wire bundle; it could have been in the wire as received or could have resulted from cold flow.
Modification procedure. MSC planned to make the changes in the Block II spacecraft by working directly from mockup to the spacecraft, using sketches and a minimum of paper work. While this kind of an operation could get a job done in a hurry, it required a strong leader, thoroughly experienced in working with engineering and factory people and procedures, and rigorous adherence to a minimal streamlined paper system. All "engineering" must be on drawings and all fabrication work must be inspected at least as rigorously as in a normal manufacturing process.

White urged close management attention to ensure quality. Memo, White to Phillips, "MSC plan presented on April 29, 1967," May 1, 1967.

May 2

The Air Force Manned Orbiting Laboratory Systems Program Office requested that MSC present a briefing to selected office and contractor personnel on NASA's progress in safety studies and tests associated with fire hazards aboard manned space vehicles. Information was requested for the MOL program to help formulate studies and activities that would not duplicate MSC efforts. The briefing was given at MSC May 10.

TWXs, MOL Systems Program Office, Los Angeles, to MSC, "Request for Briefing on Safety Studies and Associated Tests," May 2, 1967; MSC to Space Systems Div., USAF, May 3, 1967.

May 2

ASPO Manager George M. Low asked the Chairman of the Apollo 204 Review Board to consider releasing CM 014 for use in the Apollo program. If the Review Board had a continuing need for the CM, Low requested that consideration be given to release of certain individual items needed for the Apollo Mission Simulator program. Board Chairman Floyd L. Thompson notified Low on June 22 that the CM mockup and CM 014 were no longer required by the Review Board and that their disposition might be determined by the ASPO Manager.

Memo, Low to Chairman, Apollo 204 Review Board, "Release of Command Module 014," May 2, 1967; TWX, Thompson to MSC, Attn: George M. Low, June 22, 1967.

May 2-4

NASA Block II Redefinition Task Team group leaders and CSM Program Manager Kenneth S. Kleinknecht arrived at North American Aviation Space Division at Downey May 2, followed by Task Team Manager Frank Borman the next day. Borman met with North American management May 4 to ensure understanding of the team plan and objectives. An afternoon meeting with NASA and North American Task Managers and group leaders reviewed the status of the Block II Redefinition task.

Following is a summation of the technical status at the time:

Ninety-five percent of the wires and break points had been defined, including additional wires for changes (approximately 200) plus the existing open items on spacecraft 101. Schematics for manufacturing and preparation of integrated schematics were to be available May 30.
AiResearch environmental control system components had been reviewed by North American and direction transmitted for materials changes.
North American was planning no compartment closeouts behind the front panels. This was unacceptable to NASA and closeouts would be required.
North American definition and review of all spacecraft materials applications were in progress, but Borman reported the progress was too slow to date and that a plan for expediting was under consideration.
Fire extinguisher interfaces had not yet been identified. A meeting was planned during the next week to resolve the problem.
NASA reaffirmed to North American the intention that DITMCO (an inspection process) of the completed installed harness be performed as late as possible and that harness protection be reinstalled immediately after DITMCO. Connectors which could not be DITMCOed must be reviewed with NASA, connector by connector.
NASA reaffirmed that a crew compartment fit and function test was required on each spacecraft at Downey.
Two meetings had been held on the Downey spacecraft 101 test and checkout. Definition of requirements was progressing rapidly and was expected to be completed and signed off by May 5. A schedule would be prepared for distribution on May 9, for the preparation, review and final approval of the operational checkout procedures necessary for the approved test requirement. The launch site test plan for spacecraft 101 would be discussed in a meeting at Downey May 9, and this meeting would be followed by a discussion of spacecraft 2TV-1 Downey test requirements as related to the Houston tests for the spacecraft 101 mission.
The Test Group of the Task Team planned to work closely with the Checkout Working Group and would be represented in its next meeting in Downey on May 11.
Rework resulting from the wiring inspection of spacecraft 101 was not proceeding as rapidly as desired; however, Borman reported that more efficient procedures were being prepared and would be carried out as soon as possible.
The Apollo spacecraft quality requirements were being reviewed and the North American Quality Plan would be checked against these requirements in detail.

Borman reported on plans and schedules:

A documentation center was being established to provide configuration documentation to the North American and NASA teams. A master change status board would be maintained in the NASA Task Team Office, and Block II specifications would be updated to provide the predesign baseline.
North American had released Master Development Schedule-10 ahead of its May 12 schedule, and detailed engineering, manufacturing, and Apollo test operation schedules were being prepared.

Critical open items were:

TV monitor requirements and interfaces,
flashing beacon mechanization and requirements,
material for the lithium hydroxide canister,
emergency oxygen mask mechanization,
water chlorination mechanization,
rapid repressurization-mechanization or surge tank, and
cabin recirculation valve requirement.

TWX, RASPO at Downey, Calif., to distr., "Block II Redefinition Daily Report No. 1, dated May 4, 1967," May 5, 1967.

May 3

NASA's Space Science Steering Committee approved establishment of a facility on the moon consisting of arrays of solid corner reflectors. The first array was to be established by the earliest possible lunar landing mission, with other arrays to be carried on subsequent missions. Until the Committee and Manned Space Flight Experiment Board agreed on assignment of priorities among the various lunar science experiments, this experiment was to be considered a contingency experiment to be carried on a "space available" basis. The facility on the moon would be available to the principal investigator - C. O. Alley, University of Maryland - as well as to other scientists.

TWX, NASA Hq. to MSC, Attn: Robert Piland, May 3, 1967.

May 4

Directions had been prepared to designate mission AS-501 formally as Apollo 4, AS-204/LM-1 as Apollo 5, and AS-502 as Apollo 6, NASA Apollo Program Director Samuel C. Phillips informed Associate Administrator for Manned Space Flight George E. Mueller. Phillips said he thought it was the right time to start using the designations in official releases and appropriate internal documentation. Mueller concurred.

Note, Phillips to Mueller, May 4, 1967.

May 5

Circuit breakers being used in both CSM and LM were flammable, MSC ASPO Manager George Low told Engineering and Development Director Maxime A. Faget. Low said that although Structures and Mechanics Division was developing a coating to be applied to the circuit breakers, such a solution was not the best for the long run. He requested that the Instrumentation and Electronics Systems Division find replacement circuit breakers for Apollo - ideally, circuit breakers that would not bum and that would fit within the same volume as the existing ones, permitting replacement in panels already built. On July 12 Low wrote Faget again: "In light of the work that has gone on since my May 5, 1967, memo, are you now prepared to propose the use of metal-jacketed circuit breakers for Apollo spacecraft? If the answer is affirmative, then we should get specific direction to our contractors immediately. Also, have you surveyed the industry to see whether a replacement circuit breaker is available or will be available in the future?" Low requested an early reply.

Memos, Low to Faget, "Apollo circuit breakers," May 5, 1967; "Apollo circuit breakers, continued," July 12, 1967.

May 5

After review of operational considerations for a minimum restart capability in the Saturn launch vehicle's S IVB stage, MSC's Director of Flight Operations reported to NASA Hq. that an 80-minute restart capability was believed the best compromise for the early lunar missions, "for the primary reason of providing sufficient time for ground support in verifying navigation, and flight crew checkout of CSM and S-IVB systems prior to TLI [translunar injection], while providing for two injection opportunities in both the Atlantic and Pacific Oceans (second and third revolutions). For later missions, consideration should be given to the hardware implications of providing a restart capability with minimum (zero) restrictions, so that advantage may be taken of confidence in onboard systems to gain additional payload."

Ltr., Christopher C. Kraft, Jr., MSC, to NASA Hq., "S-IVB Restart Capability," May 5, 1967.

May 9-10

NASA reported to Congress on actions taken on the Apollo 204 Review Board's findings and recommendations concerning the January 27 spacecraft fire. Administrator James E. Webb, Deputy Administrator Robert C. Seamans, Jr., and Associate Administrator for Manned Space Flight George E. Mueller testified before the Senate Committee on Aeronautical and Space Sciences May 9 and before the House Committee on Science and Astronautics' Subcommittee on NASA Oversight May 10. (See also September 21 and Appendix 8.)

Senate Committee on Aeronautical and Space Sciences, Apollo Accident: Hearings, 90th Cong., 1st sess., pts. 6-7, May 9, 1967; House Committee on Science and Astronautics, Subcommittee on NASA Oversight, , 90th Cong., 1st sess, vol. 3, May 10, 1967; Astronautics and Aeronautics, 1967 (NASA SP-4008, 1968), pp. 144-148.).

May 10

MSC responded to a March 29 letter from NASA Hq. concerning two arrays of Apollo Lunar Surface Experiments Package (ALSEP) experiments. MSC said it had reviewed schedules, cost, and integration aspects of the requested configurations and that four areas of the project apparently should be modified to allow proper inclusion of the configurations:

extension of mission support efforts by Bendix Aerospace Systems Division (BxA) for the fourth ALSEP mission;
extension of KSC's support efforts by BxA for the fourth ALSEP mission;
extension of the ALSEP prototype test program to encompass three distinct system configurations rather than the two in the original plans; and
extension of the ALSEP qualification test program to encompass three distinct configurations rather than the original two.

The cost impact was estimated at $670,000, and completion of the ALSEP contract was expected to be extended three months to allow for mission support for the fourth flight.

Ltr., Robert R. Gilruth, Director, MSC, to NASA Hq., Attn: Samuel C. Phillips, "Selection of Apollo Lunar Surface Experiments Package System Configurations," May 10, 1967.

May 11

NASA Administrator James E. Webb issued a statement on selection of the Apollo spacecraft contractor: "In the 1961 NASA decision to negotiate with North American Aviation for the Apollo command and service modules, there were no better qualified experts in or out of NASA on whom I could rely than Dr. Robert Gilruth, Dr. Robert C. Seamans, and Dr. Hugh L. Dryden. These three were unanimous in their judgment that of the five companies submitting proposals, and of the two companies that were rated highest by the Source Evaluation Board, North American Aviation offered the greatest experience in developing high-performance manned flight systems and the lowest cost.

"In the selection of North American Aviation, the work of the Source Evaluation Board was not rejected or discarded. It was used as the basis for a more extensive and detailed examination of all pertinent factors than the Board had performed at the time its report was presented to Dr. Gilruth, Dr. Seamans, Dr. Dryden and to me.

"At that point it became the responsibility of NASA's Associate Administrator, Dr. Seamans; its Deputy Administrator, Dr. Dryden; and its Administrator, myself, to take all steps necessary to determine whether the facts then available formed an adequate basis for our selection of a contractor. We decided in the affirmative and then proceeded to select the contractor the facts indicated offered the most to the government."

NASA News Release 67-122, May 11, 1967.

May 12

George M. Low, Manager of the Apollo Spacecraft Program, notified NASA Hq. that Grumman was committed to a June 28 delivery for lunar module 1 (LM-1). This date included provisions for replacement of the development flight instrumentation harness with a new one. Low's assessment was that the date would be difficult to meet.

TWX, Low, MSC, to NASA Hq., Attn: Lee James, "LM-1 delivery schedule," May 12, 1967.

May 12

Anthony W. Wardell of the MSC Flight Safety Analysis Office wrote Apollo Manager Low that "the May 10 inspection further substantiates my previous recommendation to replace, rather than rework, the [spacecraft 101 wiring] harness. In addition to the visual evidence of wire damage noted, a book containing about 100 outstanding wire damage MRB (Material Review Board) actions was noted on a work table near the spacecraft." He did, however, list seven recommended suggestions to be followed in the event the harnesses were reworked rather than replaced. The suggestions were passed on to CSM Manager Kenneth S. Kleinknecht by Low in a memorandum on May 13. Low requested that the suggestions be passed to North American Aviation as soon as possible, with additional suggestions from MSC Quality Control Chief Jack A. Jones, who had also inspected the harness.

Memos, Jones to Low, "Inspection of SC-101 Wire Harness Assemblies," May 10, 1967; Wardell to Low, "Inspection of Spacecraft 101 Wiring Harnesses," May 12, 1967; Low to Kleinknecht, "Spacecraft 101 wiring," May 13, 1967

May 12

Apollo 204 Review Board Chairman Floyd L. Thompson appointed a subcommittee to examine the final report of Panel 18 and prepare recommendations regarding its acceptability for inclusion in the Board's Report. Thompson named Maxime A. Faget, MSC, to chair the subcommittee and Frank Borman, MSC, George C. White, NASA Hq., and E. Barton Geer, LaRC, as members. Thompson asked that the subcommittee forward its recommendations at the earliest possible date and that it also review the comments of North American Aviation on the validity of the findings of the Board and its Panels.

TWX, Thompson to addressees, May 12, 1967.

May 15

The NASA Block II CSM Redefinition Task Team was augmented by the assignment of Gordon J. Stoops as Group Leader-Program Control, with the following functions:

Liaison with North American Aviation Program Control and Contracts to expedite updating of the contract change authorizations and the issuance of timely program technical direction.
Liaison with the ASPO CSM project Engineering and Checkout Division and CSM Contract Engineering Branch at MSC to expedite contract change authorizations and ensure timely program technical direction.

Memo, Manager, CSM, ASPO, to distr., "Block II redefinition, command and service modules," May 15, 1967.

May 18

Prime and backup crews for Apollo 7 (spacecraft 101) were named, with the assignments effective immediately. The prime crew for the engineering-test-flight mission was to consist of Walter M. Schirra, Jr., commander; Donn F. Eisele, CM pilot; and R. Walter Cunningham, LM pilot. The backup crew was Thomas P. Stafford, commander; John W. Young, CM pilot; and Eugene A. Cernan, LM pilot. Names had been reported to the Senate Committee on Aeronautical and Space Sciences on 9 May.

Memo, Astronaut Office to distr., "Astronaut Technical Assignments," May 18, 1967; Senate committee on Aeronautical and Space Sciences, Apollo Accident: Hearings, 90th Cong., 1st sess., pt. 6, May 9, 1967.

May 19

A Block II spacecraft vibration program was begun to provide confidence in CSM integrity and qualify the hardware interconnecting the subsystems within the spacecraft. A test at MSC was to simulate the vibration environment of max-q flight conditions. The test article was to be a Block II CSM. A spacecraft-LM adapter, an instrumentation unit, and an S-IVB stage forward area simulation would also be used.

Memo, Chief, Systems Engineering Div. (MS), to Manager, ASPO, "Block II spacecraft vibration program," with encl., "Block II Spacecraft Vibration Program," May 19, 1967.

May 20

MSC notified NASA Hq. that - with the changes defined for the Block II spacecraft following the January 27 Apollo 204 fire and with CSM delivery schedules now reestablished - it was necessary to complete a contract for three additional CSMs requested in 1966. North American Aviation had responded September 15, 1966, to MSC's February 28 request for a proposal, but action on a contract had been suspended because of the AS-204 accident. NASA Hq. on June 27, 1967, authorized MSC to proceed.

TWXs, Manager, ASPO, to NASA Hq., Attn: Samuel C. Phillips, "Authorization for procurement of three additional Block II CSM's," May 20, 1967; NASA Hq., Associate Administrator for Manned Space Flight to MSC, Attn: George Low, June 27, 1967.

May 22

MSC ASPO Manager George Low informed Grumman Senior Vice President George Titterton that he had asked North American Aviation assistance in improving access to the LM when placed inside the spacecraft-lunar module adapter (SLA). He also ordered a change request, in response to Grumman's April 18 request that MSC consider an SLA design change. Low had visited the pad at KSC Launch Complex 37, agreed action was necessary, and on May 19 asked North American's Apollo Program Manager Dale D. Myers for recommendations. Low said improved access to the LM was needed "both for rapid emergency egress and for normal servicing."

An emergency method of cutting through the SLA structure in premarked locations with a "cookie cutter" portable handsaw device was adopted - primarily for exit in an emergency occurring after hypergolics were loaded into the LM.

Ltrs., Titterton to MSC, Apr. 18, 1967; Low to Myers, May 19, 1967; Low to Titterton, May 22. 1967; memo, ASPO Manager to R. W. Williams, "Preparation of change request," May 22. 1967; Myers to Low, Aug. 11, 1967.

May 25

MSC submitted requirements to KSC that TV signals from cameras inside the LM and CM be monitored and recorded during manned hazardous tests, with hatch open or closed, and tests in the Vehicle Assembly Building, launch pads, and altitude chambers. A facility camera was to monitor the propellant-utilization gauging system during propellant loading. MSC specified that the field of view of the TV camera should encompass the shoulder and torso and portions of the legs of personnel at the normal flight stations in both the CM and the LM.

Ltr., Owen G. Morris, MSC, to KSC, "Continuous Television Recording in Support of Manned Apollo Tests at KSC," May 25, 1967.

May 26

ASPO Manager George Low told Charles A. Berry, MSC Director of Medical Research and Operations, that it had been determined there was no suitable substitute for water glycol as a coolant and it would continue to be used in the Apollo spacecraft. Low recognized that it was "essential that the effects of any possible glycol spill be well defined and that procedures be established to avoid any hazardous conditions." He asked Berry's office to define the limits of exposure for glycol spills of varying quantities and for recommendations concerning cabin purge in the event of a spill. Low also wondered, assuming development of a smelling agent, if it would be possible to determine the concentration of water glycol by the strength of the smell in the spacecraft. Berry's office replied June 22 that it was working with Crew Systems Division to identify an odor additive for leak detection. They would begin a program to establish a safe upper limit for human exposure to ethylene glycol and had asked the National Academy of Sciences Committee on Toxicity for information. Animal exposure tests probably would be necessary; if they were needed, a test plan would be submitted before July 1.

Memos, Manager, ASPO, to Berry, "Water glycol toxicity," May 26, 1967; Berry to Low, June 22, 1967.

May 26

NASA Headquarters and MSC officials attended a review of the CSM at North American Aviation in Downey. Following the North American briefing, the group visited the wire-harness layout and assembly areas. NASA Associate Administrator for Manned Space Flight George E. Mueller, with Anthony W. Wardell and Jack A. Jones of MSC, inspected the wiring in spacecraft 101 and 2TV-1 in detail.

Mueller stressed the importance of improving spacecraft delivery schedules, with particular emphasis on spacecraft 020 and the second and third manned spacecraft, working up to two-month delivery intervals. He was concerned about the five- to six-week spacecraft 020 hatch delay and stated that Apollo Program Director Samuel C. Phillips must approve the proposed change. North American pointed out that it was using the resources of the corporation toward the two-month delivery schedule, and that a modification task-team approach would be used as long as it was effective in improving schedules. Tiger teams of engineering, quality, manufacturing, and materials personnel were working on wiring and plumbing in spacecraft 101. CSM Manager Kenneth S. Kleinknecht reviewed the Block II Redefinition Task Team effort for Mueller and he indicated that Phillips had considered an industry tiger team to assist in the overall spacecraft effort.

Memo, Kleinknecht to ASPO Manager, "Review of command and service modules," May 26, 1967.

May 26

Apollo 204 Review Board Chairman Floyd L. Thompson wrote NASA Deputy Administrator Robert C. Seamans, Jr., "The Apollo 204 Review Board respectfully submits that it has fulfilled all of its duties and responsibilities as prescribed by the Deputy Administrator's memorandum of February 3, 1967. Accordingly, it is requested that the Apollo 204 Review Board be dissolved."

Ltr., Thompson to Seamans, "Report of Completion of Apollo 204 Review Board Activities," May 26, 1967.

May 29

W. R. Downs, Special Assistant for Advanced Systems, MSC Structures and Mechanics Division, discovered that bare or defectively insulated silver-covered copper wires exposed to glycol/water solutions would ignite spontaneously and burn in oxygen. Copper wire or nickel-covered copper wire under identical conditions did not ignite. The laboratory results were confirmed in work at the Illinois Institute of Technology. In a June 13 memorandum, the Chief of the Structures and Mechanics Division recommended that if additional testing verified that nickel-coated wires were free of the hazard, consideration should be given to an in-line substitution of nickel-coated wires for silver-coated wires in the LM. It was understood that the Block II CSM already had nickel-coated wires. In a June 20 memo to the ASPO Manager, the Director of Engineering and Development pointed out that silver-plated pins and sockets in connectors would offer the same hazards. He added that Downs had also identified a chelating agent that would capture the silver ion and apparently prevent the reaction chain. In a July 24 memorandum, ASPO Manager George Low said that, in view of recent spills of ethylene glycol and water mixtures, spacecraft contractors North American Aviation and Grumman Aircraft Engineering had been directed to begin actions immediately to ensure that a fire hazard did not exist for the next manned spacecraft. Actions were to include identification of the location of silver or silver-covered wires and pins and of glycol spills.

Memos, Special Assistant for Advanced Systems to Chief, Structures and Mechanics Div., "Chemical reactivity of silver covered copper wires with glycol/water solutions compared to copper or nickel covered copper wires," May 29, 1967 (rev. June 12, 1967); Chief, Structures and Mechanics Div., to Director of Engineering and Development, "Silver-covered copper wires as a fire producing hazard in spacecraft," June 13, 1967; Director of Engineering and Development to Manager, ASPO, "Silver-covered copper wires as a fire producing hazard in spacecraft," June 20, 1967; Manager, ASPO, to distr., "Silver-covered copper wires as a fire producing hazard in spacecraft," July 24, 1967.

May 31

Grumman Aircraft Engineering Corp.'s method of building wiring harness for the lunar module was acceptable, George Low, MSC Apollo Spacecraft Program Office Manager, wrote Apollo Program Manager Samuel C. Phillips at NASA Hq. Low had noted on a visit to Grumman on May 9 that many of the harnesses were being built on two-dimensional boards. In view of recent discussions of the command module wiring, Low requested Grumman to reexamine their practice and to reaffirm their position on two-versus three-dimensional wiring harnesses.

In his May 31 letter to Phillips, Low enclosed Grumman's reply and said that, in his opinion, Grumman's practice was acceptable because

most wire bundles on the LM were much thinner than the CSM wiring bundles and were much more flexible;
portions of the LM harness were often fabricated on a three dimensional segment of the harness board; and
connectors were usually mounted on metal brackets with the proper direction and clocking.

Ltrs., Low to Phillips, May 31, 1967; J. G. Gavin to Low, "Use of Two and Three Dimensional Harness Boards in Fabrication of LM Wiring," May 24, 1967; Grumman LM Manufacturing Memo, W. B. Atchison to C. W. Rathke, "Harness Board Design - 2D vs. 3D," 17 May 1967.

May 31

George M. Low told Joseph N. Kotanchik, Chief of MSC's Structures and Mechanics Division, that actions were pending on Pratt & Whitney pressure vessel failures. The pressure vessels were used in the Apollo fuel cell system. Kotanchik had spelled out a list of problem areas in connection with both the vessels and management interface between MSC and principal contractor North American Aviation, and between North American and its subcontractor Pratt & Whitney.

Memos, Chief, Structures and Mechanics Div., to Manager, ASPO, "Conduct of Pratt and Whitney Aircraft (PWA) on pressure vessel failure analysis," May 18, 1967; Low to Kotanchik, "Pratt & Whitney pressure vessel failures," May 31, 1967.