Chariots for Apollo: A History of Manned Lunar Spacecraft|
Preliminary Designs for the Lunar Lander
Work at NASA's lead Apollo center on the excursion vehicle had started in late 1961, when designers began looking at the advantages of lunar-orbit rendezvous. But these had been analyses of general rather than specific configurations. Wernher von Braun's researchers in Huntsville had also studied concepts for soft landing. For landers weighing several thousand kilograms (and thus presumably manned), they considered liquid-fueled engines more practical than those using solid propellants. Houston engineers also drew on studies conducted by the Langley Research Center in Virginia. By mid-September 1961, Gilruth's people had roughly worked out a mission plan and figured out the kind of vehicle that might do the job. From September to December, they tried to nail down systems operations more precisely, particularly in such areas as propulsion and communications.31
The mysterious nature of the moon's surface received much attention, since a safe lunar landing presented some tricky design problems. Manned Spacecraft Center engineers considered such things as the effect of engine exhaust on the surface layer, the influence of dust layers on landing-gear footpads, and surface dust effects on optical and radar landing aids. Although a model of the lunar surface drawn from the best available data was used for these engineering studies, Gilruth's men realized that there were varying views among scientists about the lunar surface characteristics, especially the depth of the dust layer.32
By early 1962, spacecraft specialists had begun to move beyond the study phase. While others fought for their chosen mode, they worked out details for building the lunar module and started preparing for its procurement. The newly created Houston Apollo spacecraft office drafted a lengthy document in April defending the hardware and operational feasibility of lunar rendezvous and the excursion vehicle. Basic concepts of the mission profile and docking and of storage arrangements for the lander inside the spacecraft adapter were fairly firm. Many aspects of guidance and navigation and of operations in lunar orbit were well understood. Several theoretical vehicle shapes were depicted, velocity requirements were delineated, vehicle weights (up to 9,200 kilograms, including a 25-percent contingency margin) were estimated, and mission development plans, using the Little Joe II and the Saturn C-IB and C-5, were considered.33
William Rector was assigned to Frick's project office staff "to start worrying about the LEM." Using command module documentation as a guide, he wrote a work statement. Rector drew on technical expertise from within the project office and from other center organizations, particularly Max Faget's research and development directorate. He relied heavily on advice from the Spacecraft Research Division in preparing the procurement documents. Rector began with "a real shoestring operation," a small group of specialists for communications, propulsion, and overall configuration, and for assembling information and writing the request for proposals.
Early in May, Rector and his team finished the preliminary statement of work and started on the formal proposal request. "I'll never forget," he said later, "all we did was just sort of turn the command module upside down and put a window and a propulsion stage in it." From this point on Rector and his group continually revised the proposal, to include additional information on visibility requirements, crew location, and propulsion systems as it became available. They also took first cuts at the guidance and communications systems, among others, trying to work out the basic interrelationships for each subsystem and to get them into the work statement.34
The spacecraft office wanted the work statement in its final form by mid-July. When the early drafts went to Washington for review, Joseph Shea in the Office of Manned Space Flight insisted that the vehicle should be configured for unmanned, as well as manned, flight because NASA might want to use it to ferry large payloads to the lunar surface. Everyone in Houston, from Gilruth on down, claimed that such a lander would be unreliable. The lunar module design should not be compromised by throwing in this dual requirement.
After a series of meetings, including a last-minute session with Gilruth and Frick, Rector carried a work statement to Headquarters that left the door open for future negotiations. To avoid further delay in procurement, he had inserted a clause that obligated the contractor to study the advantages and drawbacks of automatic versus manned modes and to assist the agency in coming to a final decision. The procurement documents were approved and issued to 11 aerospace firms* during the latter half of July.35
While Houston was getting ready to procure the lander, Shea's Office of Systems was defending the agency's choice of lunar-orbit rendezvous before the President's advisers and the public. This was a time-consuming and harried process, a grinding day-by-day burden, that began even before the official announcement in July.
* Companies invited to submit proposals were Lockheed, Boeing, Ling-Temco-Vought, Northrop, Grumman, Douglas, General Dynamics, Republic Aviation, Martin-Marietta, North American, and McDonnell.
31. James P. Gardner, Harry O. Ruppe, and Warren H. Straly, "Comments on Problems Relating to the Lunar Landing Vehicle," ABMA Rept. DSP-TN-13-58, 4 Nov. 1958, passim, but esp. p. 36; Donald C. Cheatham to Chief, Flight Ops. Div., and Head, Apollo Projects Off., "Conference with Langley Research Center personnel on problems related to lunar landing operations," 14 Nov. 1961; STG, "A General Description of the Apollo 'Bug' Systems," 11 Sept. 1961; Owen E. Maynard, "A General Description of the Lunar Excursion Vehicle's Systems for Excursions from Lunar Orbit to Lunar Landing and Back to Lunar Orbit," STG, working paper no. 1028, 29 Sept. 1961; Jack W. Small to Chief, Flight Systems Div., STG, "Payload penalties and technical considerations for implementing the LEV with communication functions in addition to those which satisfy minimum requirements," 30 Nov. 1961; Richard B. Ferguson, "Propulsion Requirements for Lunar Landing Missions Employing a Detachable Lunar Lander," MSC, working paper no. 1038, 19 Dec. 1961.
32. Frank W. Casey, Jr., and Owen E. Maynard, "A Hypothetical Model of the Lunar Surface for the Engineering Design of Terminal Touchdown Systems," MSC, working paper No. 1033, 30 Nov. 1961.
33. MSC, "Lunar Orbital Technique for Performing the Lunar Mission," April 1962, passim, but esp. pp. 15-21, 57-61.
34. William F. Rector III, interview, Redondo Beach, Calif., 27 Jan. 1970; MSC Weekly Activity Report for Dir., OMSF, NASA, 29 April-5 May 1962, p. 11.
35. Rector interview; NASA, "Request for Proposals on R&D for Lunar Excursion Module," news release, unnumbered, 25 July 1962; NASA, "Request for Proposal on 'LEM,'" news release, unnumbered, 25 July 1962; "Apollo Chronology," MSC Fact Sheet 96, n.d.