Encyclopedia Astronautica
LM Mode Debate


LM Mode Debate Diary

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LM Mode Debate Chronology


1959 April 7 - .
  • Research into rendezvous techniques - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. NASA Administrator T. Keith Glennan requested $3 million for research into rendezvous techniques as part of the NASA budget for Fiscal Year 1960. In subsequent hearings, DeMarquis D. Wyatt, Assistant to the NASA Director of Space Flight Development, explained that these funds would be used to resolve certain key problems in making space rendezvous practical. Among these were the establishment of referencing methods for fixing the relative positions of two vehicles in space; the development of accurate, lightweight target-acquisition equipment to enable the supply craft to locate the space station; the development of very accurate guidance and control systems to permit precisely determined flight paths; and the development of sources of controlled power.

1959 August 31 - .
  • Lunar flights to originate from space platforms in earth orbit - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. A House Committee Staff Report stated that lunar flights would originate from space platforms in earth orbit according to current planning. The final decision on the method to be used, "which must be made soon," would take into consideration the difficulty of space rendezvous between a space platform and space vehicles as compared with the difficulty of developing single vehicles large enough to proceed directly from the earth to the moon.

1959 November 19 - .
  • Importance of weight of end vehicle in the lunar landing mission - . Nation: USA. Related Persons: Goett. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. In a memorandum to the members of the Research Steering Committee on Manned Space Flight, Chairman Harry J. Goett discussed the increased importance of the weight of the "end vehicle" in the lunar landing mission. This was to be an item on the agenda of the third meeting of the Committee, to be held in early December. Abe Silverstein, Director of the NASA Office of Space Flight Development, had recently mentioned to Goett that a decision would be made within the next few weeks on the configuration of successive generations of Saturn, primarily the upper stages, Silverstein and Goett had discussed the Committee's views on a lunar spacecraft. Goett expressed the hope in the memorandum that members of the Committee would have some specific ideas at their forthcoming meeting about the probable weight of the spacecraft.

    In addition, Goett informed the Committee that the Vega had been eliminated as a possible booster for use in one of the intermediate steps leading to the lunar mission. The primary possibility for the earth satellite mission was now the first-generation Saturn and for the lunar flight the second-generation Saturn.


1959 December 8-9 - .
  • Configurations for manned lunar landing by direct ascent - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Several possible configurations for a manned lunar landing by direct ascent being studied at the Lewis Research Center were described to the Research Steering Committee by Seymour C. Himmel. A six-stage launch vehicle would be required, the first three stages to boost the spacecraft to orbital speed, the fourth to attain escape speed, the fifth for lunar landing, and the sixth for lunar escape with a 10,000-pound return vehicle. One representative configuration had an overall height of 320 feet. H. H. Koelle of the Army Ballistic Missile Agency argued that orbital assembly or refueling in orbit (earth orbit rendezvous) was more flexible, more straightforward, and easier than the direct ascent approach. Bruce T. Lundin of the Lewis Research Center felt that refueling in orbit presented formidable problems since handling liquid hydrogen on the ground was still not satisfactory. Lewis was working on handling cryogenic fuels in space.

1960 January - .
  • Manned lunar landing and return (MALLAR) - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. The Chance Vought Corporation completed a company-funded, independent, classified study on manned lunar landing and return (MALLAR), under the supervision of Thomas E. Dolan. Booster limitations indicated that earth orbit rendezvous would be necessary. A variety of lunar missions were described, including a two-man, 14-day lunar landing and return. This mission called for an entry vehicle of 6,600 pounds, a mission module of 9,000 pounds, and a lunar landing module of 27,000 pounds. It incorporated the idea of lunar orbit rendezvous though not specifically by name.

1960 Spring - .
1960 April 5 - .
  • Houbolt paper on rendezvous in space with minimum expenditure of fuel - . Nation: USA. Related Persons: Houbolt. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. John C. Houbolt of the Langley Research Center presented a paper at the National Aeronautical Meeting of the Society of Automotive Engineers in New York City in which the problems of rendezvous in space with the minimum expenditure of fuel were considered. Additional Details: here....

1960 October 17 - .
  • Formation of a working group on the manned lunar landing program - . Nation: USA. Related Persons: Low, George. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. In a memorandum to Abe Silverstein, Director of NASA's Office of Space Flight Programs, George M. Low, Chief of Manned Space Flight, described the formation of a working group on the manned lunar landing program: "It has become increasingly apparent that a preliminary program for manned lunar landings should be formulated. This is necessary in order to provide a proper justification for Apollo, and to place Apollo schedules and technical plans on a firmer foundation.

    "In order to prepare such a program, I have formed a small working group, consisting of Eldon Hall, Oran Nicks, John Disher, and myself. This group will endeavor to establish ground rules for manned lunar landing missions; to determine reasonable spacecraft weights; to specify launch vehicle requirements; and to prepare an integrated development plan, including the spacecraft, lunar landing and takeoff system, and launch vehicles. This plan should include a time-phasing and funding picture, and should identify areas requiring early studies by field organizations."


1960 November 29 - .
  • Briefing on the Apollo and Saturn programs - . Nation: USA. Related Persons: von Braun; Faget. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. A joint briefing on the Apollo and Saturn programs was held at Marshall Space Flight Center MSFC, attended by representatives of STG and MSFC. Maxime A. Faget of STG and MSFC Director Wernher von Braun agreed that a joint STG-MSFC program would be developed to accomplish a manned lunar landing. Areas of responsibility were: MSFC launch vehicle and landing on the moon; STG - lunar orbit, landing, and return to earth.

1960 December 10 - .
  • Lunar orbit method of accomplishing the lunar landing mission - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: Representatives of the Langley Research Center briefed members of STG on the lunar orbit method of accomplishing the lunar landing mission..

1960 December 14 - .
  • Seamans briefed on the lunar orbit rendezvous method - . Nation: USA. Related Persons: Seamans. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Associate Administrator of NASA Robert C. Seamans, Jr., and his staff were briefed by Langley Research Center personnel on the rendezvous method as it related to the national space program. Clinton E. Brown presented an analysis made by himself and Ralph W. Stone, Jr., describing the general operational concept of lunar orbit rendezvous for the manned lunar landing. The advantages of this plan in contrast with the earth orbit rendezvous method, especially in reducing launch vehicle requirements, were illustrated. Others discussing the rendezvous were John C. Houbolt, John D. Bird, and Max C. Kurbjun.

1960 December 29 - .
  • Grumman began work on a lunar orbit rendezvous study - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: The Grumman Aircraft Engineering Corporation began work on a company- funded lunar orbit rendezvous feasibility study..

1961 January 5-6 - .
  • Manned lunar landing discussed with Space Exploration Program Council - . Nation: USA. Related Persons: von Braun; Faget. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. During a meeting of the Space Exploration Program Council at NASA Headquarters, the subject of a manned lunar landing was discussed. Following presentations on earth orbit rendezvous (Wernher von Braun, Director of Marshall Space Flight Center), lunar orbit rendezvous (John C. Houbolt of Langley Research Center), and direct ascent (Melvyn Savage of NASA Headquarters), the Council decided that NASA should not follow any one of these specific approaches, but should proceed on a broad base to afford flexibility. Another outcome of the discussion was an agreement that NASA should have an orbital rendezvous program which could stand alone as well as being a part of the manned lunar program. A task group was named to define the elements of the program insofar as possible. Members of the group were George M. Low, Chairman, Eldon W. Hall, A. M. Mayo, Ernest O. Pearson, Jr., and Oran W. Nicks, all of NASA Headquarters; Maxime A. Faget of STG; and H. H. Koelle of Marshall Space Flight Center. This group became known as the Low Committee.

1961 January 6 - .
  • Low Committee established - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; Apollo Lunar Landing; CSM Source Selection; LM Mode Debate; LM Source Selection. The Manned Lunar Landing Task Group (Low Committee) set up by the Space Exploration Program Council was instructed to prepare a position paper for the NASA Fiscal Year 1962 budget presentation to Congress. The paper was to be a concise statement of NASA's lunar program for Fiscal Year 1962 and was to present the lunar mission in term of both direct ascent and rendezvous. The rendezvous program would be designed to develop a manned spacecraft capability in near space, regardless of whether such a technique would be needed for manned lunar landing. In addition to answering such questions as the reason for not eliminating one of the two mission approaches, the Group was to estimate the cost of the lunar mission and the date of its accomplishment, though not in specific terms. Although the decision to land a man on the moon had not been approved, it was to be stressed that the development of the scientific and technical capability for a manned lunar landing was a prime NASA goal, though not the only one. The first meeting of the Group was to be held on January 9.

1961 January 9 - . LV Family: Nova. Launch Vehicle: Nova 4L.
  • First meeting of the Manned Lunar Landing Task Group - . Nation: USA. Related Persons: Silverstein. Program: Apollo. Spacecraft: Apollo CSM; Apollo Lunar Landing; CSM Source Selection; LM Mode Debate; LM Source Selection. At the first meeting of the Manned Lunar Landing Task Group, Associate Administrator Robert C. Seamans, Jr., Director of the Office of Space Flight Programs Abe Silverstein, and Director of the Office of Advanced Research Programs Ira H. Abbott outlined the purpose of the Group to the members. After a discussion of the instructions, the Group considered first the objectives of the total NASA program:

    1. the exploration of the solar system for knowledge to benefit mankind; and
    2. the development of technology to permit exploitation of space flight for scientific, military, and commercial uses.
    NASA's lunar program was a logical step toward these objectives. In current lunar program planning, three steps were projected:

    1. a manned landing on the moon with return to earth,
    2. limited manned lunar exploration, and
    3. a scientific lunar base.
    To accomplish the first step, a great increase in launch vehicle capability would be needed beyond that provided by current funding. A comparison of a three-million-pound-thrust and a six-million-pound-thrust Nova launch vehicle was made. It was estimated that a 60,000- to 80,000-pound payload to escape velocity would be needed for a manned lunar landing mission.

1961 January 10 - .
  • Conference on lunar orbit rendezvous for the Apollo program - . Nation: USA. Related Persons: Maynard. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. A conference was held at the Langley Research Center between representatives of STG and Langley to discuss the feasibility of incorporating a lunar orbit rendezvous phase into the Apollo program. Attending the meeting for STG were Robert L. O'Neal, Owen E. Maynard, and H. Kurt Strass, and for the Langley Research Center, John C. Houbolt, Clinton E. Brown, Manuel J. Queijo, and Ralph W. Stone, Jr. The presentation by Houbolt centered on a performance analysis which showed the weight saving to be gained by the lunar rendezvous technique as opposed to the direct ascent mode. According to the analysis, a saving in weight of from 20 to 40 percent could be realized with the lunar orbit rendezvous technique.

1961 January 11 - .
  • Briefing given to the Saturn Guidance Committee on the Apollo program - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. J. Thomas Markley of the Apollo Spacecraft Project Office reported to Associate Director of STG Charles J. Donlan that an informal briefing had been given to the Saturn Guidance Committee on the Apollo program. The Committee had been formed by Don R. Ostrander, NASA Director of the Office of Launch Vehicle Programs, to survey the broad guidance and control requirements for Saturn. The Committee was to review Marshall Space Flight Center guidance plans, review plans of mission groups who intended to use Saturn, recommend an adequate guidance system for Saturn, and prepare a report of the evaluation and results during January. Members of STG, including Robert O. Piland, Markley, and Robert G. Chilton, presented summaries of the overall Apollo program and guidance requirements for Apollo.

1961 January 16-17 - .
  • Second meeting of the Low Committee - . Nation: USA. Related Persons: Low, George. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. At the second meeting of the Manned Lunar Landing Task Group (Low Committee), a draft position paper was presented by George M. Low, Chairman. A series of reports on launch vehicle capabilities, spacecraft, and lunar program support were presented and considered for possible inclusion in the position paper.

1961 January 24 - .
  • Low Committee first draft report - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. The Manned Lunar Landing Task Group (Low Committee) submitted its first draft report to NASA Associate Administrator Robert C. Seamans, Jr. A section on detailed costs and schedules still was in preparation and a detailed itemized backup report was expected to be available in mid- February.

1961 January 25 - .
  • Study on the feasibility of refueling a spacecraft in orbit - . Nation: USA. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. Summary: NASA announced that the Lockheed Aircraft Corporation had been awarded a contract by the Marshall Space Flight Center to study the feasibility of refueling a spacecraft in orbit..

1961 April 19 - .
  • Manned Lunar Landing via Rendezvous report - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. A circular, "Manned Lunar Landing via Rendezvous," was prepared by John C. Houbolt from material supplied by himself, John D. Bird, Max C. Kurbjun, and Arthur W. Vogeley, who were members of the Langley Research Center space station subcommittee on rendezvous. Other members of the subcommittee at various times included W. Hewitt Phillips, John M. Eggleston, John A. Dodgen, and William D. Mace.

1961 May 25 - .
  • Lundin Committee to assess Lunar landing mission - . Nation: USA. Related Persons: Seamans. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Robert C. Seamans, Jr., NASA's Associate Administrator, requested the Directors of the Office of Launch Vehicle Programs and the Office of Advanced Research Programs to bring together members of their staffs with other persons from NASA Headquarters to assess a wide variety of possible ways of accomplishing the lunar landing mission. This study was to supplement the one being done by the Ad Hoc Task Group for Manned Lunar Landing Study (Fleming Committee) but was to be separate from it. Additional Details: here....

1961 May - .
  • Lunar orbit rendezvous plan - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: Basic concepts of the lunar orbit rendezvous plan were presented to the Lundin Committee by John C. Houbolt of Langley Research Center..

1961 June 16 - .
  • Fleming Committee Report: lunar mission could be accomplished within the decade - . Nation: USA. Related Persons: Seamans. Program: Apollo. Spacecraft: Apollo CSM; CSM Source Selection; LM Mode Debate; LM Source Selection. The Fleming Committee, which had been appointed on May 2, submitted its report to NASA associate Administrator Robert C. Seamans, Jr., on the feasibility of a manned lunar landing program. The Committee concluded that the lunar mission could be accomplished within the decade. Chief pacing items were the first stage of the launch vehicle and the facilities for testing and launching the booster. It also concluded that information on solar flare radiation and lunar surface characteristics should be obtained as soon as possible, since these factors would influence spacecraft design. Special mention was made of the need for a strong management organization.

1961 June 26 - .
  • Langley Research Center lunar landing paper - . Nation: USA. Related Persons: Faget. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Maxime A. Faget, Paul E. Purser, and Charles J. Donlan of STG met with Arthur W. Vogeley, Clinton E. Brown, and Laurence K. Loftin, Jr., of Langley Research Center on a "lunar landing" paper. Faget's outline was to be used, with part of the information to be worked up by Vogeley.

1961 June - .
  • Lunar orbit rendezvous briefing - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: Members of Langley Research Center briefed the Heaton Committee on the lunar orbit rendezvous method of accomplishing the manned lunar landing mission..

1961 September 14 - .
  • Studies being done on rendezvous modes for accomplishing a manned lunar landing - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. In a memorandum to the Large Launch Vehicle Planning Group (LLVPG) staff, Harvey Hall of NASA described the studies being done by the Centers on rendezvous modes for accomplishing a manned lunar landing. These studies had been requested from Langley Research Center, Marshall Space Flight Center, and the Jet Propulsion Laboratory on August 23. STG was preparing separate documentation on the lunar orbit rendezvous mode. An LLVPG team to undertake a comparative evaluation of rendezvous and direct ascent techniques had been set up. Members of the team included Hall and Norman Rafel of NASA and H. Braham and L. M. Weeks of Aerospace Corporation.

    The evaluation would consider:

    • Effect of total flight time on specifications and reliability of equipment and on personnel.
    • Effect of vehicle system reliability in each case, including the number of engine starts and restarts.
    • Dependence on data, data-rate, and distance from ground station for control of assembly and refueling operations
    • Launch and injection windows
    • Effect of differences in the total weight propelled to earth escape velocity
    • Relative merits of lunar gravity and of a lunar base in general versus an orbital station for rendezvous and assembly purposes.
    Reliability estimates on vehicles would be based on LLVPG data; estimates on equipment would rely on experience with similar types in known applications.

1961 October 31 - .
  • Manned Lunar-Landing through use of Lunar-Orbit Rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Under the direction of John C. Houbolt of Langley Research Center, a two-volume work entitled "Manned Lunar-Landing through use of Lunar-Orbit Rendezvous" was presented to the Golovin Committee (organized on July 20). The study had been prepared by Houbolt, John D. Bird, Arthur W. Vogeley, Ralph W. Stone, Jr., Manuel J. Queijo, William H. Michael, Jr., Max C. Kurbjun, Roy F. Brissenden, John A. Dodgen, William D. Mace, and others of Langley. The Golovin Committee had requested a mission plan using the lunar orbit rendezvous concept. Bird, Michael, and Robert H. Tolson appeared before the Committee in Washington to explain certain matters of trajectory and lunar stay time not covered in the document.

1961 November 15 - .
  • Houbolt letter on lunar orbit rendezvous (LOR) plan - . Nation: USA. Related Persons: Seamans. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. In a letter to NASA Associate Administrator Robert C. Seamans, Jr., John C. Houbolt of Langley Research Center presented the lunar orbit rendezvous (LOR) plan and outlined certain deficiencies in the national booster and manned rendezvous programs. This letter protested exclusion of the LOR plan from serious consideration by committees responsible for the definition of the national program for lunar exploration.

1962 January-June - .
  • Grumman study on lunar orbit rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. The Grumman Aircraft Engineering Corporation developed a detailed, company-funded study on the lunar orbit rendezvous technique: characteristics of the system (relative cost of direct ascent, earth orbit rendezvous, and lunar orbit rendezvous); developmental problems (communications, propulsion); and elements of the system (tracking facilities, etc.). Joseph M. Gavin was appointed in the spring to head the effort, and Robert E. Mullaney was designated program manager.

1962 February 6 - .
  • Langley presentation of lunar orbit rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: John C. Houbolt of Langley Research Center and Charles W. Mathews of MSC made a presentation of lunar orbit rendezvous versus earth orbit rendezvous to the Manned Space Flight Management Council..

1962 March 1 - .
  • Chance Vought to study spacecraft rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. NASA Headquarters selected the Chance Vought Corporation of Ling-Temco-Vought, Inc., as a contractor to study spacecraft rendezvous. A primary part of the contract would be a flight simulation study exploring the capability of an astronaut to control an Apollo-type spacecraft.

1962 March 29 - .
  • Chance Vought briefed on lunar orbit rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Members of Langley Research Center briefed representatives of the Chance Vought Corporation of Ling- Temco-Vought, Inc., on the lunar orbit rendezvous method of accomplishing the lunar landing mission. The briefing was made in connection with the study contract on spacecraft rendezvous awarded by NASA Headquarters to Chance Vought on March 1.

1962 April 16 - .
  • Lunar orbit rendezvous technique - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Summary: Representatives of MSC made a formal presentation at Marshall Space Flight Center on the lunar orbit rendezvous technique for accomplishing the lunar mission..

1962 April 24 - .
  • Indecision on the lunar mission mode causing delays in Apollo program - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; Apollo Lunar Landing; LM Mode Debate; LM Source Selection. MSC Associate Director Walter C. William reported to the Manned Space Flight Management Council that the lack of a decision on the lunar mission mode was causing delays in various areas of the Apollo spacecraft program, especially the requirements for the portions of the spacecraft being furnished by NAA.

1962 April 24 - . LV Family: Saturn V. Launch Vehicle: Saturn V.
  • Rosen recommends Saturn C-5 design and lunar orbit rendezvous - . Nation: USA. Related Persons: Rosen, Milton. Program: Apollo. Spacecraft: Apollo LM; Apollo Lunar Landing; CSM Recovery; LM Mode Debate; LM Source Selection. Milton W. Rosen, NASA Office of Manned Space Flight Director of Launch Vehicles and Propulsion, recommended that the S-IVB stage be designed specifically as the third stage of the Saturn C-5 and that the C-5 be designed specifically for the manned lunar landing using the lunar orbit rendezvous technique. The S-IVB stage would inject the spacecraft into a parking orbit and would be restarted in space to place the lunar mission payload into a translunar trajectory. Rosen also recommended that the S- IVB stage be used as a flight test vehicle to exercise the command module (CM), service module (SM), and lunar excursion module (LEM) (previously referred to as the lunar excursion vehicle (LEV)) in earth orbit missions. The Saturn C-1 vehicle, in combination with the CM, SM, LEM, and S-IVB stage, would be used on the most realistic mission simulation possible. This combination would also permit the most nearly complete operational mating of the CM, SM, LEM, and S-IVB prior to actual mission flight.

1962 April - .
  • Advantages of lunar orbit rendezvous - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. John C. Houbolt of Langley Research Center, writing in the April issue of Astronautics, outlined the advantages of lunar orbit rendezvous for a manned lunar landing as opposed to direct flight from earth or earth orbit rendezvous. Under this concept, an Apollo-type spacecraft would fly directly to the moon, go into lunar orbit, detach a small landing craft which would land on the moon and then return to the mother craft, which would then return to earth. The advantages would be the much smaller craft performing the difficult lunar landing and takeoff, the possibility of optimizing the smaller craft for this one function, the safe return of the mother craft in event of a landing accident, and even the possibility of using two of the small craft to provide a rescue capability.

1962 May 3 - .
  • Presentation on the lunar orbit rendezvous technique - . Nation: USA. Related Persons: Holmes, Brainard. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. A presentation on the lunar orbit rendezvous technique was made to D. Brainerd Holmes, Director, NASA Office of Manned Space Flight, by representatives of the Apollo Spacecraft Project Office. A similar presentation to NASA Associate Administrator Robert C. Seamans, Jr., followed on May 31.

1962 June 22 - .
  • Results of the study on lunar mission mode selection - . Nation: USA. Related Persons: Shea. Program: Apollo. Spacecraft: Apollo CSM; LM Mode Debate; LM Source Selection. Joseph F. Shea, NASA Deputy Director of Manned Space Flight (Systems), presented to the Manned Space Flight Management Council the results of the study on lunar mission mode selection. The study included work by personnel in Shea's office, MSC, and Marshall Space Flight Center. The criteria used in evaluating the direct ascent technique, earth orbit rendezvous connecting and fueling modes, and lunar orbit rendezvous were: the mission itself, weight margins, guidance accuracy, communications and tracking requirements, reliability (abort problems), development complexity, schedules, costs, flexibility, growth potential, and military implications.

1962 July 30 - . LV Family: Nova; Saturn V.
  • Conclusions on the selection of a lunar mission mode based on studies conducted in 1961 and 1962 - . Nation: USA. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. The Office of Systems under NASA's Office of Manned Space Flight summarized its conclusions on the selection of a lunar mission mode based on NASA and industry studies conducted in 1961 and 1962:

    • There were no significant technical problems which would preclude the acceptance of any of the modes, if sufficient time and money were available. (The modes considered were the C-5 direct ascent, C-5 earth orbit rendezvous (EOR), C-5 lunar orbit rendezvous (LOR), Nova direct ascent, and solid-fuel Nova direct ascent.)
    • The C-5 direct ascent technique was characterized by high development risk and the least flexibility for further development.
    • The C-5 EOR mode had the lowest probability of mission success and the greatest development complexity.
    • The Nova direct ascent method would require the development of larger launch vehicles than the C-5. However, it would be the least complex from an operational and subsystem standpoint and had greater crew safety and initial mission capabilities than did LOR.
    • The solid-fuel Nova direct flight mode would necessitate a launch vehicle development parallel to the C-5. Such a development could not be financed under current budget allotments.
    • Only the LOR and EOR modes would make full use of the development of the C-5 launch vehicle and the command and service modules. Based on technical considerations, the LOR mode was distinctly preferable.
    • The Directors of MSC and Marshall Space Flight Center had both expressed strong preference for the LOR mode.
    On the basis of these conclusions, the LOR mode was recommended as most suitable for the manned lunar landing mission. (The studies summarized in this document were used by the Manned Space Flight Management Council in their mission mode decision on June 22.)

1962 October 24 - .
  • Final manned lunar landing mode report - . Nation: USA. Related Persons: Kennedy; Wiesner. Program: Apollo. Spacecraft: Apollo LM; LM Mode Debate; LM Source Selection. Faced by opposition of mode selection by Jerome Wiesner, Kennedy's science adviser, NASA let contracts to McDonnell and STL for direct two-man flight modes. Both concluded that it was feasible but would require LH2/LOX stages for descent and ascent from lunar surface, which NASA/STG adamantly opposed. This was also the last stab - for the time being - at 'lunar Gemini'.

    The Office of Systems under NASA's Office of Manned Space Flight completed a manned lunar landing mode comparison embodying the most recent studies by contractors and NASA Centers. The report was the outgrowth of the decision announced by NASA on July 11 to continue studies on lunar landing modes while basing planning and procurement primarily on the lunar orbit rendezvous (LOR) technique. Additional Details: here....


1962 December 10 - .
  • Selection of lunar orbit rendezvous for Apollo explained to Kennedy - . Nation: USA. Related Persons: Webb. Program: Apollo. Spacecraft: Apollo LM; Apollo Lunar Landing; LM Mode Debate. NASA Administrator James E. Webb, in a letter to the President, explained the rationale behind the Agency's selection of lunar orbit rendezvous (rather than either direct ascent or earth orbit rendezvous) as the mode for landing Apollo astronauts on the moon. Arguments for and against any of the three modes could have been interminable: "We are dealing with a matter that cannot be conclusively proved before the fact," Webb said. "The decision on the mode . . . had to be made at this time in order to maintain our schedules, which aim at a landing attempt in late 1967."

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