Tardy deliveries by subcontractors were among the bigger stumbling blocks that North American faced in putting the command and service modules together. Eberhard Rees, an expert in manufacturing management from Marshall Space Flight Center, was lent to George Low, Apollo program manager at the Manned Spacecraft Center, to solve fabrication problems. In the later months of 1967, Rees visited North American and soon realized that cooperation between the prime contractor and the subsystem suppliers was not close enough. North American engineers, he said, should spend more time at the subcontractors' plants while subsystem assemblies were in critical stages of fabrication. He also recommended that North American borrow some inspectors from General Electric to help conduct vendor surveys, specification reviews, and test failure assessments.3
The subsystem situation came to the attention of George Mueller, Associate Administrator for Manned Space Flight at Headquarters, when he visited Downey late in 1967. Mueller on his return to Washington asked Edgar M. Cortright, his deputy, to go to the major companies, review the status of hardware, and see if the condition could be improved.4
During January and February 1968, Cortright traveled to nine Apollo subcontractors. He was impressed with people, equipment, and facilities but not at all pleased with hardware or schedules. Cortright found that neither North American nor Grumman knew enough about the status of their subcontractors' work to be able to forecast deliveries with any degree of accuracy. The subcontractors, Cortright also said, should be more aware of the importance of their systems in the total program - they should not just deliver their products to the dock in Downey or Bethpage and walk away. He was upset about failures in electronic parts, especially when he found that the subcontractors were doing their best to solve their problems by themselves by trial and error. Low asked the Houston subsystem managers to look into these deficiencies and correct them.5
Just the barest hint of something wrong with electrical parts, anything that might be a fire hazard, captured the immediate attention of special guardian groups. Spacecraft wiring and materials, cabin atmospheres, and crew safety were the subjects of many meetings. Third-party groups, such as a Senior Flammability Board, a Materials Selection Review Board, and a Crew Safety Review Board, were set up to ensure extra safeguards.
Late in 1967, Houston Director Robert Gilruth led a contingent of NASA officials to a meeting with William Bergen and his staff at North American* to discuss flammability problems of the coaxial cable in the command module. Under particular scrutiny was spacecraft 101, slated for the first manned Apollo mission. After visually inspecting the vehicle and watching motion picture films of tests, the group concluded that 23 meters of the coaxial cable might be flammable. There were several options on what to do about it - replace it, wrap it with aluminum tape, partially wrap it to provide fire breaks, or leave it alone. Since other spacecraft wiring and electrical equipment might be damaged during replacement, even with extreme care, they decided it would be safer to fly 101 essentially as it was, with the exception of one bundle that would be wrapped.** 6
No sooner had one NASA group acted than another demanded a defense of what had been done. Aleck C. Bond, speaking for the Houston Materials Selection Review Board, queried Low about the cable. Low pointed out that the decision had been made at the highest Apollo management level of both North American and NASA. He also reminded Bond that, in the NASA system of checks and balances, the board did not approve changes. It only recommended approval or disapproval. Low then required that all deviations be assessed by his Configuration Control Board and forwarded to Apollo Program Manager Phillips in Washington for final review.7
Most of the Flammability Board's attention focused on cabin atmosphere at the launch site, which also affected materials selection. Established in September 1967, with Gilruth as chairman, the board directed several series of tests under a variety of atmospheric mixtures and pressures for pad operations. Thirty-eight tests had been completed by 7 January 1968. In the middle of the month, a second series began, using principally a 60-per-cent-oxygen and 40-percent-nitrogen mix (normal atmosphere is 21 percent oxygen and 78 percent nitrogen, with traces of other gases). This series ended on 25 January, and evaluations began.
Max Faget, whose engineers in Houston ran many tests for Gilruth's board, said they used pure oxygen at a higher than normal pressure on the pad to check for air leaks from the cabin. After the Apollo 204 fire, everyone was aware that this was dangerous. They then ran pure oxygen tests at one-third the pressure (which simulated orbital conditions). With cabin fans off and no other means of spreading the flames, they found that fire would not propagate as rapidly in space. So Faget's group agreed that if they could make the spacecraft safe on the ground, it would be safe during flight.
But there was no way to put 100-percent-fireproof materials in the spacecraft, especially in the electrical system. Many persons began campaigning for a two-gas atmosphere, with a higher concentration of nitrogen than oxygen. Use of this mixture would have required completely rebuilding the spacecraft to withstand the pressures of a sea-level atmosphere. The command module could withstand only about half that pressure in space, and the lunar module even less. Moreover, a mixed atmosphere in space would complicate the environmental system - Faget said the system "would get confused and would put too much nitrogen in the cabin, a very insidious thing because there was no way to detect [it]." The astronauts would just get sleepy - and die. Another complication was that a switch back and forth from the two-gas system in the cabin and the 100 percent oxygen in the hoses connected to the suits might give the crew aeroembolism, or the bends.
So the question was twofold: How much nitrogen was needed on the pad to prevent fire? And how much oxygen was needed during launch while the cabin pressure relief valve was venting? Tests revealed that a 60-percent-oxygen and 40-percent-nitrogen mixture at a pressure of 11.2 newtons per square centimeter (16.2 pounds per square inch) on the pad would result in 1.4 newtons (2 psi) in orbit after venting, which would give a partial pressure of oxygen compatible with the oxygen atmosphere and pressure in the suits. The cabin pressure would be lower at first, but the mixture would be breathable and it would sustain life. In fact, by the time the craft reached orbit, Faget said, the cabin mixture would actually be about 80 percent oxygen. And there was a bonus in this arrangement beyond the safety factor: no structural changes were needed in the spacecraft to accommodate this combination of oxygen and nitrogen.8
Low promised Phillips a decision on the prelaunch atmosphere in time for spacecraft 101's Design Certification Review. A third set of tests, using boilerplate 1224, confirmed conclusions drawn from the second series. Gilruth's Flammability Board met on 4 March and recommended the 60/40 mixture for the launch pad. On 7 March, Mueller's Certification Board accepted this recommendation. In April, NASA's medical group, expressed "enthusiastic approval of the . . . decision to adopt the 60/40 atmosphere."9
For a while there was a good deal of discussion about the lunar module cabin atmosphere on the launch pad. Low recommended 100 percent oxygen for the LM, since there was no crew and little electrical power in the vehicle during launch. Moreover, the spacecraft-lunar module adapter, which held the lander, was filled with nitrogen, reducing flammability hazards to almost nothing. This procedure, Low pointed out, would save some of the lander's oxygen supply, as well as minimizing crew procedures in changing the mixture to pure oxygen after launch. Marshall, however, objected, because any oxygen escaping from the lander during the launch phase might come in contact with hydrogen leaking from the S-IVB into the adapter and start a fire. Houston conceded that the advantages of launching the lunar module with pure oxygen had to give way to Huntsville's concerns; the atmosphere in the lander's cabin at launch would not exceed 20 percent oxygen.10
Another set of watchdogs, formed to consider manned operation of the machines, was the Apollo Crew Safety Review Board. Since Gilruth's team mas investigating "spacecraft fire safety and air-on-the-pad," the new group, at its first meeting in March 1968, began looking for problems that might be missed by other specialized committees. Led by John Hodge in Houston, the board concentrated on operations - all activities from the time the crew boarded the spacecraft through the launch phase - searching for weak links and hazards. One big worry that had to be faced was the possibility of a Saturn engine shutting down on the pad or during the launch trajectory.11
The Hodge Board was not the only group worrying about a Saturn V engine malfunction. Major General David M. Jones, Commander of the Eastern Test Range, reminded KSC Director Kurt Debus that the launch vehicle would remain over the Cape area for almost two minutes. Jones wanted the vehicle to move out over water as quickly as possible. Debus told Phillips what Jones had asked, adding that the launch azimuth should not be tampered with, since a wide range would be needed for a lunar launch. Phillips turned to Marshall for an answer, and the launch vehicle engineers modified the pitch program so the vehicle would head eastward sooner after launch than originally planned.12
Although the Saturn V may have been the key vehicle for escaping the earth's gravity for the lunar trip, the keystone in the arch leading to the surface of the moon itself was the lunar module. At least, that was the way the Flight Operations Division in Houston viewed LM-1's upcoming trial in earth orbit.13 And the path to the launch pad for that craft had been a long and arduous one.
* On 22 September 1967, North American Aviation and the Rockwell-Standard Corporation had merged into a single company, North American Rockwell Corporation, which was then divided into two major elements - the Commercial Products Group and the Aerospace and Systems Group. For consistency and brevity, this history will refer to the latter as "North American."
** Since they were not as far down the production line as 101, spacecraft 103 through 106 would have their coaxial cables removed and wrapped, which should not take longer than five days. Later spacecraft would be fitted with coaxial cables that met nonmetallic materials guidelines.
3. NASA, "James Webb NASA Management Changes Press Conference," 12 Oct. 1967; Eberhard F. M. Rees to George M. Low, "Brief survey of CSM at NAR, Downey," 17 Nov. 1967; Ivan D. Ertel and Roland W. Newkirk with Courtney G. Brooks, The Apollo Spacecraft: A Chronology, vol. 4, January 21, 1966-July 13, 1974, NASA SP-4009 (Washington, 1978) ; George W. S. Abbey, ASPO Staff Meeting, 24 June 1968.
4. Mueller, NASA OMSF, to Edgar M. Cortright and Maj. Gen. Samuel C. Phillips, no subj., 16 Dec. 1967.
5. Cortright TWX to Low and Rees, 29 Jan. 1968; Cortright memo for record, "Apollo subcontractor review," 12 March 1968; Cortright to James C. Elms, "Visits to Apollo subcontractors," 13 March 1968; Low to William M. Bland, Jr., "Approval of certification test requirements," 26 April 1968; Low to NASA Hq., Attn.: Phillips, "Apollo subcontractor review," 30 April 1968; MSC Weekly Activity Report for week ending 17 Nov. 1967,
6. MSC news release 68-3, 27 Jan. 1968; Low to Phillips, 7 March 1968; Low memo for record, "Command Module coax cable flammability considerations," 19 Dec. 1967, MSC, "CSM 101 Coax Cable Ignition Source Study," TDR 68-053, 1 March 1968; MSC, Apollo Spacecraft Program Quarterly Status Report no. 23, 31 March 1968, p. 13; NAR, North American Rockwell Corporation A First Look, brochure (Calif., September 1967); Kleinknecht to Mgr., ASPO, "Command module coax cable decisions relative to spacecraft 103 and subsequent," 9 Jan. 1968.
7. Aleck C. Bond to Mgr., ASPO, "Unilateral approval of Apollo spacecraft materials usage deviations," 26 Dec. 1967; Low to Bond, "Approval of spacecraft materials usages deviations," 6 Jan. 1968; Abbey to Paul E. Purser, "Status of actions taken on the AS-204 Review Board report," 7 Feb. 1968.
8. Low to William B. Bergen, 19 Sept. 1967; Robert R. Gilruth, chm., Senior Flammability Review Board Meeting, 13 Jan. 1968; MSC news release 68-1, 15 Jan. 1968; Apollo Weekly Status Report for week ending 26 Jan. 1968, p. 1; Richard W. Bricker, "Report to Flammability Test Review Board: Results of BP-1224 Apollo Command Module Mockup Flammability Test in 60 Percent Oxygen/40 Percent Nitrogen at 16.2 PSIA Total Pressure," Apollo working paper, review copy, 26 Jan. 1968; Maxime A. Faget, interview, Houston, 22 Nov. 1976.
9. Low to Aaron Cohen, "Spacecraft 101 DCR," 7 Feb. 1968; Gilruth, Senior Flammability Review Board Meeting, 4 March 1968; NASA OMSF Report to the Admin., NASA, signed by Mueller (hereafter cited as Mueller Report), 11 March 1968; Quarterly Status Rept. no. 23, pp. 8-9, 34; Jerry W. Craig to Chief, Systems Engineering Div., "Review of BP 1224 test data with I. Pinkel and R. Van Dolah," 19 April 1968; Low to Phillips, 2 May 1968, with enc., Robert W. Van Dolah to Craig, 26 April 1968.
10. Low to Dir., Flight Crew Ops., "Oxygen in the LM at launch," 28 Nov. 1967; Low to Phillips, Rear Adm. Roderick O. Middleton, KSC, and Arthur Rudolph, MSFC, 22 April 1968, with enc.; Rudolph to MSC, Attn.: Low, "LM Cabin Atmosphere," 17 May 1968, with encs., Charles C. Wood to Charles T. Boone, Jr., "Revised Spacecraft/IU/S-IVB Interstage," 7 May 1968, and Boone to MSC Mechanical Panel Cochairman, Attn.: Lyle M. Jenkins, "LM Cabin Atmosphere," n.d.; Low to MSFC, Attn.: Lee B. James, "LM cabin atmosphere," 29 June 1968.
11. John D. Hodge, chm., minutes of Crew Safety Review Board Meetings, 13 March, 20-21 March, 27-29 March, 9-11 April, 16-18 April, 24-26 April, and 21 May 1968; Phillips to MSC, KSC, and MSFC, Attn.: Low, Middleton, James, and William Teir, "Apollo Crew Safety Review Board," 17 June 1968.
12. Bass Redd to Mgr., ASPO, "Analysis of a Saturn V pitch program modification (S-tilt), proposed as an aid to reducing the land impact probability after a low altitude launch escape vehicle (LEV) abort," 13 Dec. 1967; Middleton to MSFC, Attn.: Mgr., Saturn V Program Office, "Saturn V Range Safety Problem," 7 Feb. 1968; Kurt H. Debus to Phillips, 8 Feb. 1968; Phillips to MSFC, Attn.: Rudolph and Teir, "Apollo Lift-off Hazards," 11 Dec. 1967; Phillips to Debus, 26 Feb. 1968.
13. MSC Flight Control Div., "AS-204/LM-1 Mission Operations Review," 15 Nov. 1967, p. 3.