Chariots for Apollo: A History of Manned Lunar Spacecraft|
The Lunar Module and the Apollo Program
Although configuration was not settled and major subsystems development was not begun until near the end of 1964, NASA had begun taking stock of where the lunar module stood in relation to other pieces of Apollo. Structural connections between the lunar module and other Apollo hardware were confined primarily to the command and service modules and the adapter. Unlike its scratchy relations with MIT, Grumman's association with North American was smooth.* Early meetings between the contractors were devoted to hardware designs and docking requirements. Initially, each manufacturer was to design and test all equipment mounted on his own vehicle, but in March 1963 North American assumed responsibility for the complete docking device as well as the adapter structure.
Late in 1963, design engineers from Downey recommended, and NASA approved, a center probe and drogue for docking. Stowage of the lander in the adapter was settled in October 1963, when the contractors and Houston agreed upon a truncated cone, 8.8 meters long, with the lunar module mounted against the interior wall by a landing-gear outrigger truss. Thereafter, detailed design focused on the dynamic loads expected during launch and on the deployment of the four panels for removal of the lander during flight. Grumman sent North American a mockup to use in confirming the structural mounting and panel opening characteristics.41
Lunar module ground testing to prove the practicality of the design and flight testing to verify the spaceworthiness of the flight vehicle also had to be worked into overall Apollo plans. Gilruth had stated that one fundamental requirement for mission success was employing "the kind of people who will not permit it to fail." The basic reliability philosophy, he said, was "that every manned spacecraft that leaves the earth . . . shall represent the best that dedicated and inspired men can create. We cannot ask for more; we dare not settle for less." As the lander grew larger and more complex, it became, in the eyes of some observers, the "most critical part of the [Apollo] vehicle." The many things that could doom the crew made ground-testing all the more important. Reliability for the lander dictated either redundant systems or, where that was impractical because of weight and size, ample margins of safety.
Grumman's basic plan for ground testing, set forth in May 1963, called for extensive use of test models and lunar test articles (called "TMs" and "LTAs" by the engineers), as well as for propulsion rigs to test propellant lines and for engine firing programs. Because the lander's flight would be brief, Bethpage engineers adopted a practice of testing hardware until it failed, to provide an indication of strength and to gather information on failure points. Ground testing began with individual parts and subsystems and progressed upward, before the spacecraft was committed to flight.42
Bethpage came up with a scheme for testing the lander in simulated flight by powering the vehicle with six jet engines, to overcome the pull of gravity, and using a modified descent engine to practice maneuvering the vehicle. Although the idea appeared workable, it would be both costly and complex. There were also suggestions for swinging the lander from a gantrylike frame at Langley or from a helicopter or a blimp at White Sands. After a second look, the last two were also scrapped. Grumman and Houston hoped that the lunar landing training vehicle being developed by Bell could test some of the flight components at least, but installing extra equipment might slow the development of the training vehicle. A few flight instruments and the hand controller might be incorporated at a later date into the training vehicle, which the astronauts would use to practice simulated lunar landings. Flight testing within the earth's atmosphere was finally ruled out when Langley discovered in wind tunnel investigations that the Little Joe II-lander combination would be aerodynamically unstable.43
Grumman had wanted some unmanned missions, using the Little Joe II and the Saturn IB launch vehicles, before men flew the lunar lander. Houston authorized the procurement of autopilots for unmanned spacecraft but did not actually schedule any such flights. After Mueller invoked the all-up concept, with each flight groomed as though it were the ultimate mission, Houston planners began to think about putting both the lander and the North American spacecraft aboard a single Saturn IB. One Houston engineer even went to Huntsville to ask von Braun about the possibility of increasing the launch vehicle's payload capacity. And there was some discussion about strapping Minuteman missile solid-fueled rocket stages onto the launch vehicle to provide the extra boost needed!
In the meantime, ground testing would have to carry the burden of qualifying the lander until the Saturn was ready to fly the vehicle, which caused some realignment of the lunar module program. Eleven flight vehicles and two flight test articles were earmarked for Saturn development flights. NASA also decided that the first three flight vehicles must be able to fly either manned or unmanned.44
In November 1964, Shea, Mueller, and Phillips decided on a tentative flight schedule. Saturn IB missions 201, 202, 204, and 205 would be Block I command module flights. There was no assignment for 203 at this time. Shea told the Houston senior staff that it looked as though an unmanned lander might be flown on 206. The first flight of a combined Block II command module and lunar module would be Mission 207 in July 1967. By that time, the Saturn V was expected to be ready to take over the job of flying the missions.45
The lunar module had to be worked into Apollo facilities, as well as into flight schedules. Grumman had its own testing equipment in Bethpage and on the Peconic River, both on Long Island. But the lander's propulsion systems would have to be tested at the Air Force's Arnold Center and at White Sands. Fitting the lunar module into the launch complex at the Cape raised some interesting issues. One of the earliest was the rule that any vehicle flown from there must carry a destruct mechanism, in case a mission had to be aborted shortly after launch. The rule was based on a philosophy that it was better to explode propellants in the air than to have them burst into flame on the ground. Houston, however, refused to put a destruct button in the vehicle that was intended to land men on the moon, with the gruesome possibilities of a malfunction on the lunar surface that would either kill the astronauts outright or leave them stranded. Eventually, the Air Force Range Safety Officer agreed to drop this requirement for the lander.46
A difficult task at all locations, Bethpage included, was getting ground support equipment (GSE) ready to check out the lunar module subsystems. Traditionally, GSE has been a problem, since it cannot be designed and built until the spacecraft design is fairly firm. Because the lander was the first of its kind and changed from day to day as the mission requirements changed, Grumman was even slower than other contractors in getting its checkout equipment on the line. Shea complained that "the entire GSE picture at Grumman looks quite gloomy." He insisted that Grumman use some equipment that North American had developed for the command module. The situation had improved by the end of 1964, but much work was yet to be done over the next two years before the equipment could be considered satisfactory47
By mid-1964, both the lander and the command module were beginning to experience the weight growth that seems inevitable in spacecraft development programs. Von Braun promised Mueller in May that he would try to get an extra 2,000 kilograms of weight-lifting capability from the Saturn V, which eased some of the pressure on Gilruth's team in Houston. Even so, the lander was getting dangerously fat, moving steadily toward its top limit of 13,300 kilograms. Most of the weight-reducing talent in Houston was busy with the command module, whose Block II configuration was not as well defined at the time as the lander's. Several modifications in the landing vehicle were suggested, but any that limited either operational flexibility or reliability were resisted. Moreover, the lander was so unlike other spacecraft that projections were almost useless in estimating future weight increases. Containing this growth would be a major project during the coming year.48
The years 1963 and 1964 had seen the lunar module move from the drawing boards to the manufacturing line. During 1965, hardware fabrication, assembly, and testing would begin. After that, it would take only a few steps to put the craft into space. These steps, though few after the spacecraft design had been "frozen," would not be easy ones. There proved to be several more pitfalls to overcome. Some of these problems - difficulty with combustion in the ascent propulsion system, for example - were resolved only a short time before the mission that fulfilled Apollo's goal of landing men on the moon.
* The two contractors had worked together amicably enough on the Project Christmas Present Report (detailed vehicle test plan), led by North American, and on the Apollo Mission Planning Task Force, headed by Grumman. Both are discussed in Chapter 5.
41. Shea to Mueller, 29 July 1964; Newlander to Actg. Mgr., RASPO-GAEC, "Trip . . . to MSC on March 12 and 13, 1963 to attend Mechanical Systems Meeting," 15 March 1963; C. A. Rodenberger to Chief, Structural-Mechanical Syst. Br., "Trip to NAA to Discuss LEM Adapter Structural Design," 9 Aug. 1963; Rector to LEM Proc. Off., "Request for CCA, Drogue Design and Manufacture," 1 June 1964; Henry P. Yschek to North American, contract change authorization no. 2, rev. ], 29 March 1963; MSC. abstract of Structural-Mechanical Systems Meeting no. 17. 21-22 May 1963; Rector TWX to Grumman, Attn.: Mullaney, 19 Oct. 1964; Piland TWX to MSFC, Attn.: Joachim P. Kuettner, 21 Oct. 1963; Maynard to Grumman, Attn.: Mullaney, "Implementation of Actions Recommended in Apollo Program Systems Meetings," 5 Dec. 1963; Yschek to North American, contract change authorization no. 166, 19 March 1964; Rector to Chief, CSM CEB, "LEM/Adapter Mockup," 20 April 1964.
42. Robert R. Gilruth, "MSC Viewpoints on Reliability anti Quality Control," paper presented before American Institute of Architects, Houston, 15 Nov. 1962, reprinted as NASA/MSC Fact Sheet 93, title as above, p. 10; William F. Rector III, "LEM Lesson: Reliability As Never Before," Grumman Horizons 4 (1964): 20-23; Grumman, "The Test Plan for the Lunar Excursion Module, Project Apollo," 1. "Summary of Ground and Flight Tests," LPL-600-1, 15 May 1963; Grumman Report no. 8, LPR-10-24, 10 Oct. 1963, p. 45; Grumman, "LTA Program presented to NASA/NAA, 13 June 1963"; Maynard to Grumman. Attn.: Mullaney, "Lunar Landing Test Program." 10 Dec. 1963; letter, Piland to MSFC, Attn.: Alvin Steinberg, "Determination of Reliability Achievement," 23 Aug. 1963; George E. Mueller, ["Discussion of Objectives of U.S. Manned Space Flight Goals"], address to 1966 Annual Symposium on Reliability, San Francisco, 26 Jan. 1966; Mueller, "Apollo Program," no. 3 in series of lectures at University of Sydney, Australia, 10-11 Jan. 1967. pp. 13-14; Shea, untitled luncheon speech, n.d. [probably April 1963], p. 7.
43. Project Apollo Quarterly Status Report no. 3, for period ending 31 March 1963, p. 47; Zavasky, minutes of MSC Senior Staff Meeting, 29 March 1963, p. 4; Donald R. Bellman to Chief, Research Div., "Meeting of the LEM-LTA-9 committee at MSC, Houston, Texas, October 18, 1963," 21 Oct. 1963; Newlander to Small, "Trip . . . to FRC on 4/21/64," 24 April 1964; Rector to Grumman, Attn.: Mullaney, "Use of Flight Research Center LLRV for LEM Flight Control System Testing and Programming of LTA-9 anti WSMR Static Test Article," 4 June 1964; Rector to Shea, "Status Report, LEM LLRV," 20 July 1964; Rector to Grumman, Attn.: Mullaney, "Use of Flight Research Center LLRV for LEM Flight Control System Testing," 12 Aug. 1964; Grumman, "LEM Requirement Study for Little Joe II Flight," 13 June 1963; Aleck C. Bond to ASPO, Attn.: William W. Petynia. "LEM/LJ-II longitudinal vibrations," 24 June 1963; Chilton to ASPO, Attn.: Paul E. Fitzgerald, "Performance study of the Little Joe II booster with the LEM as the payload," 2 July 1963, with encs.; Decker TWX to Grumman, Attn.: Mullaney, 21 Aug. 1963; Grumman Report no. 11, p. 42; Axel T. Mattson, LaRC, memo, 7 Aug. 1964; Shea memo, "Cancellation of LEM/LJ II Program," 10 Feb. 1964; Rector to Robert E. Vale, "Cancellation of LEM-LJ II Test Program," 25 Feb. 1964, with encs.
44. Alfred D. Mardel to Mgrs., Syst. Integration et al., "Review of the Preliminary LEM Flight Test Plan from Grumman," 11 Feb. 1963, with encs.; Donald R. Segna to Mgr., ASPO, "Trip Report to Grumman, February 5, 1963," 12 Feb. 1963; Rector to Mgr., Flight Proj. Off., "Comments on GAEC Preliminary LEM Flight Test Plan!' 19 Feb. 1963; Thomas F. Baker to Frank W. Casey, Jr., "Mission Profile for a Saturn IB-Launched LEM," 11 June 1964, with enc.; Small to Decker, "Unmanned LEM Development Flights," 17 May 1963; Mueller to Dirs., MSC, LOC, and MSFC, "Manned Space Flight Schedule," 18 Nov. 1963; Rector TWX to Grumman, Attn.: Mullaney, "LEM Flight Development Plans," 10 Sept. 1964; Baker memo for file, "Test planning direction provided Apollo spacecraft contractors to date," 24 Sept. 1964.
45. John B. Lee, recorder, minutes of MSC Senior Staff Meeting, 6 Nov. 1964; William Lee to Apollo Trajectory Support Off., Attn.: Cohen, "Mission Objectives and Profile Requirements for Mission 206A, LEM Development (Unmanned Launch)," 6 Nov. 1964; Shea to Phillips, 1 Dec. 1964.
46. Col. Jean A. Jack to MSC, Attn.: Baker, "FY 64-65 Apollo Test Support at AEDC," 16 Nov. 1962; Frick to Jack, 12 Dec. 1962; Goree to Dep. Mgr., LEM, "Visit to Arnold Engineering Development Center for Discussion of Potential LEM Test Requirements, May 14, 1963," 20 May 1963; AEDC TWX to MSC, 17 Jan. 1964; Shea TWX to AEDC, Attn.: DCS/Test, 17 Feb. 1964; Madyda to Chief, Prop. and Energy Syst. Div., "Trip to AEDC to attend the Ascent Engine Development Test Coordination Meeting," 19 March 1964; Madyda to LEM PO, "Availability of Lewis altitude test facilities for LEM propulsion," 17 March 1964; Maynard to SEDD, Attn.: Pohl, "LEM Reaction Control System (RCS) Testing and Facility Requirements at White Sands Missile Range (WSMR)," 5 Sept. 1963; Jack B. Hartung to Actg. Mgr., ASPO, "Trip . . . to Cape Canaveral on August 29, 1963," 3 Sept. 1963; Kraft memo, "Aspects of Apollo Range Safety," 1 Nov. 1963; William Lee to Mgr., ASPO, "Apollo Range Safety Policy," 27 Oct. 1964; William Lee to Chief, Mission Feasibility Br., "Range Safety characteristics of Apollo spacecraft propellants," 24 Nov. 1964.
47. Shea to Mullaney, 17 Dec. 1964; Rector to Grumman, Attn.: Mullaney, "Common Use GSE Meeting," 20 Dec. 1963, with enc., abstract of proceedings of GSE Common Use Meeting, 17 Dec. 1963; idem, "Common Use GSE," 29 Jan. 1964, with enc.; Paul E. Purser, recorder, minutes of MSC Senior Staff Meeting, 18 Dec. 1964, p. 4.
48. Maynard to Mgr., CSM Eng. Off., "LEM Design Goal and Control Weights," 5 Aug. 1963; Maynard to Dep. Mgr., LEM, "LEM Weight," 9 Aug. 1963; Decker to Mgr., Syst. Integration, "Spacecraft Weights," 27 Sept. 1963; Paul E. Cotton, notes on 22 April 1964 meeting between Mueller, Gilruth, Wernher von Braun, and Kurt H. Debus, 1 May 1964; Zavasky, minutes of MSC Senior Staff Meeting, 22 May 1964, p. 4; Rector to Shea, "LEM Weight Report (LED-490-8, dated May 1, 1964)," 1 June 1964; Newlander to Small, "Trip . . . to MSC on 6/12/64," 15 June 1964; Newlander to Small and Gaylor, "Weight control," 20 Aug. 1964; Maynard to Mgr., ASPO, "Spacecraft weight status summary," 13 Nov. 1964, with enc.