Chariots for Apollo: A History of Manned Lunar Spacecraft|
The LM: Some Questions, Some Answers
Following Apollo 5, it appeared likely that one of the six flights planned for 1968 might be canceled. Fewer flights should mean a better chance of landing a crew on the moon within the decade. After reading a preliminary version of the mission report, Phillips wired the three manned space flight centers not to plan a second unmanned lunar module mission. Shipment of LM-2 and its Saturn IB booster to the Cape was delayed, pending an assessment by George Mueller's Certification Board. On 6 and 7 March, the board agreed there was no reason for another unmanned lunar module flight. The first lunar module to carry men would be launched by a Saturn V later in 1968.21
The lander still had hurdles to clear, however, before anyone would be allowed to ride it in space. Ascent engine instability, for example, had been a matter of concern from August 1967 to June 1968. When Mueller and Phillips visited the builder of the engine in the summer of 1967, they agreed that Bell had a good chance of solving fuel-injector problems and getting a stable engine ready for the first manned lander. Nevertheless, NASA had hired Rocketdyne to develop an alternate injector, sending Cecil R. Gibson from the Houston center to work with Bill Wilson at Rocketdyne. This contract lasted for about a year, and Gibson and Wilson successfully stayed on schedule, held down costs, and got the job done.22
One question that arose was whether a new and improved injector should be flown in a manned lander without a thorough revalidation test program. Joseph G. Thibodaux (Gibson's boss and chief of the Propulsion and Power Division in Houston, who had been asked to head a team to evaluate the injector) believed that it would be safe, so long as fuel did not enter the firing chamber before oxidizer. An Agena engine that had allowed the fuel to go first in the Gemini program had exploded during 1965.23
Grumman and NASA officials met on 29 April to discuss the status of the injector. They were not happy with what they had discovered during visits to the subcontractor plants. Bell had been lax in configuration control, and Rocketdyne was having trouble getting engines to start and then to run smoothly. For some time, NASA Headquarters had considered asking Rocketdyne and Bell, even though they were competitors, to pool their knowledge to get the best possible injector. Rocketdyne might send its injector and some of its personnel to the Bell test cell for checkout. Although hesitant at first, because this might slow down Bell's work, Houston told Grumman to coordinate this combined testing, calling on specialists from both subcontractors for help.24
As time passed, Phillips and Low began to worry more and more about what would happen if the Rocketdyne injector were picked. How much testing would have to be done to make certain that a Rocketdyne engine was safe enough for a crew to fly on LM-3? And how long would it take?25
Numerous trips were made to Bell by NASA officials, trying to get a grip on the problem. In May, after one visit, Low wrote: "If stability were the only criterion for acceptance, then a decision to select the Rocketdyne engine would have been clear. However, the Rocketdyne engine has also some short-comings, which are not yet completely understood." Low also believed that, if Rocketdyne were picked, it would take some "extraordinary efforts to integrate the new engine into the LM." That same month, a group led by Phillips of NASA and Joseph Gavin of Grumman met to discuss the alternatives they faced: (1) to use the Bell engine and Bell injector, (2) to ship Bell engines to Rocketdyne for fitting with Rocketdyne injectors, or (3) to send Rocketdyne injectors to Bell for installation in the Bell engine. Low finally decided to use a Bell engine and a Rocketdyne injector, with the entire assembly being put together and furnished by Rocketdyne.26
At 17 and 19 June program reviews at Rocketdyne and Bell, respectively, Low learned that qualification tests were progressing with such excellent results (the engine had gone through 53 good tests) that an end to qualification by mid-August seemed possible.27 Success now appeared certain, but the race with the decade was becoming very close.
Although the ascent engine was the most serious lander problem, there were others that created worries. For example, a window blew out of LM-5 during a test. On another occasion, a window fractured during a 72-hour high-temperature test. Corning Glass Works immediately began improving the panes, producing what Mueller called the strongest windows ever put in a spacecraft. And Grumman instigated a series of pressure tests to qualify the new windows.28 All this took time.
Still another area that raised a red flag of concern was the discovery of stress corrosion cracks in the lander's aluminum structural members. This meant replacements and still more lost time, which angered George Mueller. He reminded Gilruth that these aluminum tubes (made of an alloy called "7075 T6") had caused problems in the past. Mueller could not understand why the cracks had not been noticed earlier. He wanted a "stress corrosion team" to find out why detection had failed and to figure out how to prevent a recurrence. Gilruth replied that there was no need for a special team. Stress corrosion surveys had been conducted in 1964, but the job simply "was not handled properly on the last go-round." Low then asked Joseph Kotanchik, a Houston structures expert, to investigate the overall stress corrosion problem and to look into all equipment furnished by suppliers to the prime contractors to make sure no problems were lurking in any of these systems.29
By mid-February 1968, Grumman had inspected six landers (LM-3 through LM-8), examining more than 1,400 different components. Some parts were buried so deeply in the structure that they could not be reached. When no major cracks were found in the accessible areas, Grumman assumed that the problem was not as bad as NASA thought. Grumman did strengthen any parts not yet assembled by replacing the 7075 T6 tubes with 7075 T73, a heavier alloy. By the end of the month, Mueller told Webb he was no longer worried about stress corrosion.30
Another nagging problem in the lander was broken wiring. Brigadier General Carroll H. Bolender, Manned Spacecraft Center's lunar module manager, received the impression when visiting the Cape that the wiring was in poor shape in LM-2 and not much better in LM-3. Bolender told his resident Apollo spacecraft representative at the Grumman plant in New York to emphasize to Grumman's engineering team the need to assist manufacturing in the wiring of the spacecraft. Some improvement came from this move, but not much. During an inspection of LM-3, several broken wires were discovered, apparently caused by carelessness during rework after testing. Toward the end of April 1968, fixtures were installed to protect vulnerable wire bundles and technicians were ordered to be more careful when working in the confined spacecraft areas, easing the problem to a certain extent. But the lander's schedule was getting tighter and tighter.31
And the vehicle was steadily getting fatter. Reductions were urged, but reducing diets in 1968 were nothing like those in 1965, when 1,100 kilograms were shaved from the lander. NASA used the incentive contract as a lever to get Grumman moving on weight reduction, starting the second quarter of 1968 with the goal of cutting 22 kilograms off the ascent stage and 68 off the descent stage.32
All in all, the chances for launching a manned lunar module during 1968 seemed very slim in June of that year. And Saturn V, the launcher, was still giving program officials some anxious moments.
21. Minutes, LM-2 Flight Requirement Meeting, 26 Jan. 1968; Phillips TWX to MSC et al., 29 Jan. 1968; Abbey, ASPO Staff Meeting, 29 Jan. 1968; MSC news release 68-5, 30 Jan. 1968; Phillips TWX to MSC et al., 12 Feb. 1968; Walter A. Pennino TWX to all NASA centers, 16 March 1968.
22. MSC news release 67-48, 2 Aug. 1967; Phillips to Low, 16 Aug. 1967; William G. Gisel to Gilruth, 20 Nov. 1967, with enc., Gisel to Phillips, 20 Nov. 1967; Low to NASA Hq., Attn.: Phillips, "Ascent engine program plan," 9 Dec. 1967; Phillips TWX to Low, 27 Dec. 1967; Quarterly Status Rept. no. 21, for period ending 30 Sept. 1967, p. 18; Faget interview.
23. Quarterly Status Rept. no. 22, for period ending 31 Dec. 1967, p. 28; Martin L. Raines to Mgr., ASPO, "Trip Report - Rocketdyne January 5, 1968," 8 Jan. 1968; Brig. Gen. Carroll H. Bolender, LM Mgr., MSC, to Mgr., ASPO, "Ascent engine," 25 Jan. 1968; Joseph G. Thibodaux, Jr., to Dir., E&D, MSC, "Action item from OMSF Management Council," 4 March 1968, with enc., "Use of a New Injector in the Ascent Engine on LM-3," nd.; Low to Phillips, 27 March 1968, with enc., [Thibodaux], "Use of a New Injector in the Ascent Engine oil LM-3," n.d.
24. Minutes of Ascent Engine Meeting, signed by Bolender for NASA and Joseph G. Gavin, Jr., for Grumman, 29 April 1968; Low to Bolender, "Design freeze of ascent engine," 1 May 1968; Phillips to Low, 6 May 1968; Low to Bolender, "Bell ascent engine," 11 May 1968; Cortright to Phillips, "Interchange of information between Bell Aerospace and Rocketdyne," 21 March 1968; Phillips to Cortright, "Interchange of information between Bell Aerospace and Rocketdyne," 2 April 1968; Bolender to Mgr., ASPO, "Ascent engine," 27 Jan. 1968; Ralph H. Tripp TWX to MSC, Attn.: Gilruth et al., "LM Ascent Engine Proposed Test of the Rocketdyne Engine in the Bell Test Facility," 1 May 1968; Gavin, draft letter to MSC, Attn.: Low, "Proposed Evaluation of Bell and Rocketdyne Injectors for the LM Ascent Engine," n.d.; Low to Bolender, "Ascent engine selection," 15 March 1968.
25. Bolender to Mgr., ASPO, "LM-3 APS Engine Change Out Schedule Impact," 15 March 1968; Low to Phillips, 30 March 1968; Phillips to Low, 16 April 1968.
26. Low to H. J. McClellan, 18 May 1968; Low memo for record, "Ascent engine injector," 31 May 1968; MSC news release 68-41, 4 June 1968; Ertel and Newkirk, Apollo Spacecraft Chronology, 4.
27. Mueller Report, 21 June 1968.
28. Quarterly Status Rept. no. 22, p. 29; Low to Joseph N. Kotanchik, "CSM/LM Structural Review," 21 Dec. 1967; Low TWX to NASA Hq., Attn.: Phillips, "Replacement of Windows on LM-1," 28 Dec. 1967; RASPO/Bethpage Weekly Status Report, 4 Jan. 1968; James J. Shannon TWX to C. William Rathke, "Pressure Test of LM Windows," 16 Jan. 1968; Low to Bolender, "Actions resulting from Saturday's meeting," 19 Feb. 1968; Mueller Report, 26 Feb. 1968; Owen G. Morris to Mgrs., ASPO and LM, "Docking window failure," 6 May 1968; Orvis E. Pigg and Stanley P. Weiss, "Spacecraft Structural Windows," Apollo Experience Report (AER), NASA Technical Note (TN) S-377 (JSC-07074), review copy, July 1973.
29. Low to Edward Z. Gray, 20 Dec. 1967; Low to Kotanchik, 21 Dec. 1967; Phillips to Assoc. Admin., OMSF, "LM Stress Corrosion", 27 Dec. 1967; Mueller to Gilruth, 8 Jan. 1968; Low to Kotanchik, "Stress corrosion," 15 Jan. 1968; minutes of GAEC/MSC Meeting at MSC on 17 Feb. 1968 Low to Dale D. Myers, 21 Dec. 1967; Gilruth to Mueller, 18 Jan. 1968; Low to Gray, 20 Dec. 1967, with encs., William F. Rector III to Grumman, Attn.: Robert S. Mullaney, "Stress Corrosion," 12 Oct. 1964, and Rathke to MSC, Attn.: Rector, "Stress Corrosion," 30 Oct. 1964.
30. Bolender to Mgr., ASPO, "Stress Corrosion Review," 25 Jan. 1968; Shannon TWX to Grumman, Attn.: Rathke, "LM Landing Gear Stress Corrosion Investigation," 29 Jan. 1968; Stress Corrosion Review Progress Report, 16 Feb. 1968; Low to Bolender, 19 Feb. 1968; Mueller Report, 26 Feb. 1968; Stanley P. Weiss, "Lunar Module Structural System," AER TN S-345 (MSC-04932), June 1972.
31. Low to Bolender, no subj., 16 Feb. 1968; Bolender to Low, interoffice routing slip, 17 Feb. 1968; Bolender to Mgr., ASPO, "Wiring," 28 March 1968, and "Wire problem on LM-3," 15 April 1968.
32. J. C. Stark, interoffice memo, to Llewellyn J. Evans (Grumman President), George F. Titterton, and R. Hutton, "LM Weight Status Report," 29 Jan. 1968; Low to Evans, 20 March 1968; Owen E. Maynard, chm., LM Weight Reduction Task Force Meeting, 29 March 1968; Abbey, ASPO Staff Meeting, 29 Jan. 1968; Configuration Control Board Meeting, 5 April 1968; "LM Hardware Weight Reductions: Initial Submittal," Grumman, 5 April 1968.