The Apollo spacecraft weights had been apportioned within an assumed 90,000 pound limit. This weight was termed a "design allowable." A lower target weight for each module had been assigned. Achievement of the target weight would allow for increased fuel loading and therefore greater operational flexibility and mission reliability. The design allowable for the command module was 9,500 pounds; the target weight was 8,500 pounds. The service module design allowable was 11,500 pounds; the target weight was 11,000 pounds. The S-IVB adapter design allowable and target weight was 3,200 pounds. The amount of service module useful propellant was 40,300 pounds design allowable; the target weight was 37,120 pounds. The lunar excursion module design allowable was 25,500 pounds; the target weight was 24,500 pounds.
North American completed a study of CSM-LEM transposition and docking. During a lunar mission, after the spacecraft was fired into a trajectory toward the moon, the CSM would separate from the adapter section containing the LEM. It would then turn around, dock with the LEM, and pull the second vehicle free from the adapter. The contractor studied three methods of completing this maneuver: free fly-around, tethered fly- around, and mechanical repositioning. Of the three, the company recommended the free fly-around, based on NASA's criteria of minimum weight, simplicity of design, maximum docking reliability, minimum time of operation, and maximum visibility.
Also investigated was crew transfer from the CM to the LEM, to determine the requirements for crew performance and, from this, to define human engineering needs. North American concluded that a separate LEM airlock was not needed but that the CSM oxygen supply system's capacity should be increased to effect LEM pressurization.
On November 29, North American presented the results of docking simulations, which showed that the free flight docking mode was feasible and that the 45-kilogram (100-pound) service module (SM) reaction control system engines were adequate for the terminal phase of docking. The simulations also showed that overall performance of the maneuver was improved by providing the astronaut with an attitude display and some form of alignment aid, such as probe.
The first meeting of the LEM Flight Technology Systems Panel was held at MSC. The panel was formed to coordinate discussions on all problems involving weight control, engineering simulation, and environment. The meeting was devoted to a review of the status of LEM engineering programs.
North American, NASA, and Grumman representatives discussed three methods of descent from lunar parking orbit:
A LEM crew systems meeting was held at Grumman. The standing arrangement proposed for the crew promised to reduce the weight of the LEM by as much as 27.2 kilograms (60 pounds), and would improve crew mobility, visibility, control accessibility, and ingress-egress. Pending more comprehensive analysis, crew systems designers also favored the revised front-face configuration.
MSC representatives visited Grumman for a preliminary evaluation of the Apollo space suit integration into the LEM. A suit failure ended the exercise prematurely. Nonetheless, leg and foot mobility was good, but the upper torso and shoulder needed improvement.
On October 11, MSC Crew Systems Division (CSD) tested the suit's mobility with the portable life support system (PLSS). CSD researchers found that the PLSS did not restrict the wearer's movement because the suit supported the weight of the PLSS. Shifts in the center of gravity appeared insignificant. The PLSS controls, because of their location, were difficult to operate, which demanded further investigation.
Langley Research Center's Lunar Landing Research Facility was nearing completion. A gantry structure 121.9 meters (400 feet) long and 76.2 meters (250 feet) high would suspend a model of the LEM. It would sustain five-sixths of the model's weight, simulating lunar gravity, and thus would enable astronauts to practice lunar landings.
An MSC Spacecraft Technology Division Working Group reexamined Apollo mission requirements and suggested a number of ways to reduce spacecraft weight: eliminate the free-return trajectory; design for slower return times; use the Hohmann descent technique, rather than the equal period orbit method, yet size the tanks for the equal period mode; eliminate the CSM/LEM dual rendezvous capability; reduce the orbital contingency time for the LEM (the period of time during which the LEM could remain in orbit before rendezvousing with the CSM); reduce the LEM lifetime.
ASPO reviewed Grumman's evaluation of series and parallel propellant feed systems for the LEM ascent stage. Because of the complications involved in minimizing propellant residuals in a parallel system, a series feed appeared preferable, despite an increase in LEM structural weight. Further study of the vehicle showed the feasibility of a two-tank configuration which would be lighter and have about the same propellant residual as the four-tank series-feed arrangement.
Grumman proposed a two-tank ascent stage configuration for the LEM. On January 17, 1964, ASPO formally concurred and authorized Grumman to go ahead with the design. The change was expected to reduce spacecraft weight by about 45 kilograms (100 pounds) and would make for a simpler, more reliable ascent propulsion system. ASPO also concurred in the selection of titanium for the two propellant tanks.
North American gave a presentation at MSC on the block change concept with emphasis on Block II CSM changes. These were defined as modifications necessary for compatibility with the LEM, structural changes to reduce weight or improve CSM center of gravity, and critical systems changes. [Block I spacecraft would carry no rendezvous and docking equipment and would be earth-orbital only. Block II spacecraft would be flight-ready vehicles with the final design configuration for the lunar missions.]
MSC and North American representatives discussed preliminary analysis of the probabilities of mission success if the spacecraft were hit by meteoroids. The contractor believed that pressurized tankage in the SM must be penetrated before a failure was assumed. To MSC, this view appeared overly optimistic. MSC held that, as the failure criterion, no debris should result from meteoroid impact of the SM outer structure. [This change in criteria would cost several hundred pounds in meteoroid protection weight in the SM and LEM.] North American thought that penetration of one half the depth of the heatshield on the conical surface of the CM was a failure. Here, MSC thought the contractor too conservative; full penetration could probably be allowed.
At an Apollo Program Review held at MSC, Maxime A. Faget reported that Crew Systems Division had learned that the metabolic rate of a man walking in an unpressurized suit was twice that of a man in everyday clothes. When the suit was pressurized to 1.8 newtons per square centimeter (3.5 psi), the rate was about four times as much. To counteract this, a watercooled undergarment developed by the British Ministry of Aviation's Royal Aircraft Establishment was being tested at Hamilton Standard. These "space-age long johns" had a network of small tubes through which water circulated and absorbed body heat. Advantages of the system were improved heat transfer, low circulating noise levels, and relatively moderate flow rates required. An MSC study on integration of the suit with the LEM environmental control system showed a possible weight savings of 9 kilograms (20 pounds).
NASA gave credit to two MSC engineers, George C. Franklin and Louie G. Richard, for designing a harness system for the LEM that enabled the crew to fly the vehicle from a standing position. Eliminating the seats reduced the LEM's weight and gave the crew better visibility and closer observation of controls and instruments.
NASA and Grumman representatives discussed a weight reduction program for the LEM. Changes approved at the M-5 mockup review portended an increase in LEM separation weight of from 68 to 453 kg (150 to 1,000 lbs). Both parties agreed to evaluate the alternatives of either resizing the spacecraft or finding ways to lighten it about nine percent, thus keeping the improved LEM within the present control weight.
The trajectory summary of the Design Reference Mission (DRM) prepared by the Apollo Mission Planning Task Force was sent to Grumman by the LEM Project Office with a note that the operational sequence-of-events would be forwarded in November.
It was acknowledged that a single mission could not serve to "completely define all the spacecraft functional requirements" but "such a mission has considerable value as a standard for various purposes on the Apollo Program."
Specifically, the DRM would be used for weight reporting, electrical power reporting, reliability modeling, engineering simulation, crew task analyses, mission-related Interface Control Documents, and trade-off studies.
Dalmo-Victor studied thermal-demanded weight increases for the LEM's steerable antenna. Investigators reported to Grumman and RCA that, in the plume of the CSM's reaction control engines, 1.18 kg (2.5 lbs) was necessary merely for the survival of the antenna; another 1.18 kg would be required for tracking during this impingement.
The Structures and Mechanics Division (SMD) summarized the thermal status of antennas for the Apollo spacecraft (both CSM and LEM). Generally, most troubles stemmed from plume impingement by the reaction control or radiation from the service propulsion engines. These problems, SMD reported, were being solved by increasing the weight of an antenna either its structural weight or its insulation; by shielding it from the engines' exhaust; by isolating its more critical components; or by a combination of these methods.
The Preliminary Design Review of the Block II CM was held at North American's Downey, Calif., plant. Ten working groups evaluated the spacecraft design and resolved numerous minor details. They then reported to a review board of NASA and North American officials. This board met in Houston during the middle of the month, reviewed the findings of the working groups, and submitted recommendations to ASPO. Several significant problems required the attention of Apollo managers at Houston and at North American:
The first meeting of the Configuration Control Board was held at MSC with ASPO Manager Joseph F. Shea as chairman. Approval was given to delete 10 Apollo guidance and navigation systems; and W. F. Rector III was directed to look into the use of computers and prototype units for electronic systems integration. In other actions, a decision on changes to CSM specifications to provide for the heavyweight LEM (a proposed increase from 12,705 to 14,515 kg [28,000 to 32,000 lbs]) was deferred until the next meeting; and Owen Maynard was directed to identify all Block II changes that must be implemented regardless of impact and have them ready for Board action by February 18, 1965.
MSC canceled plans (originally proposed by North American) for a device to detect failures in the reaction control system (RCS) for Block I CSMs. This was done partly because of impending weight, cost, and schedule penalties, but also because, given an RCS failure during earth orbit, the crew could detect it in time to return to earth safely even without the proposed device. This action in no way affected the effort to devise such a detection system for the Block II CSM or the LEM, however.
William F. Rector III, MSC's LEM Project Officer, reported at an ASPO Manager's Staff Meeting that the expected firing date for the heavyweight ascent (HA) rig #3 at WSTF had been slipped from March 18, 1965, until April 13. Grumman personnel at White Sands said the slip was necessary because
Missiles and Rockets reported a statement by Joseph F. Shea, ASPO manager, that MSC had no serious weight problems with the Apollo spacecraft. The current weight, he said, was 454 kg (1,000 lbs) under the 40,823 kg (90,000 lb) goal. Moreover, the increased payload of the Saturn V to 43,091 kg (95,000 lbs) permitted further increases. Shea admitted, however, that the LEM was growing; recent decisions in favor of safety and redundancy could raise the module's weight from 13,381 kg to 14,575 kg (29,500 lbs to 32,000 lbs).
MSC defined the functional and design requirements for the tracking light on the LEM:
Systems Engineering Division (SED) reviewed the Flight Operations Directorate's recommendation for an up-data system in the LEM during manned missions. (Currently the LEM's guidance computer received data either from the computer in the CSM or from MSC.) SED concluded that, because the equipment was not essential for mission success, an up-data system did not warrant the cost and weight penalties ($750,000 and 4.54 kg [10 lbs]) that it would entail.
Crew Systems Division (CSD) decided on a single garment for both thermal and micrometeoroid protection for Apollo astronauts. CSD's Richard S. Johnston summarized factors underlying this decision:
ASPO overruled a recommendation by the Flight Operations Directorate for an up-data link in the LEM. Although an automated means of inserting data into the spacecraft's computer was deemed "highly desirable," there were prohibitive consequences:
ASPO reviewed Grumman's recommendation for a combination of supercritical and gaseous modes for storing oxygen in the LEM's environmental control system (ECS). MSC engineers determined that such an approach would save only about 14.96 kg (33 lbs) over a high- pressure, all-gaseous design. Mission objectives demanded only four repressurizations of the LEM's cabin. On the basis of this criterion, the weight differential was placed at less than nine pounds.
As a result of this analysis, MSC directed Grumman to design the LEM ECS with an all-gaseous oxygen storage system.
Engineers from General Electric and MSC's Crew Systems and Systems Engineering Divisions determined that transferring water from the CSM to the LEM involved a 5.4-kg (12-lb) increase in the latter's separation weight. Grumman had placed the penalty at only l.8 kg (4 lbs). Because the LEM's weight was so critical, the water transfer scheme was canceled.
ASPO requested the Apollo Program Director to revise the LEM control weight at translunar injection as follows:
The question of whether a data tape recorder would be installed on LEM-1 had been discussed at several Apollo 206 Mission Operations Plan meetings and there was a strong possibility it would not be installed.
In a memorandum to ASPO Manager Joseph F. Shea, Assistant Director for Flight Operations Christopher C. Kraft, Jr., pointed out that his Directorate had responsibility to ASPO of insuring "that all possible test objectives are accomplished. This is done not only by real-time conduct of the mission, but also through considerable premission planning which integrates the desired profile with the Manned Space Flight Network. The underlying purpose of all these operations activities is the accumulation of data, which for unmanned, nonrecoverable spacecraft such as LEM-1 can only be provided through the use of RE telemetry. The FOD (Flight Operations Directorate) does not believe the Apollo 206A Mission Objectives can be assured of being accomplished without the addition of a data tape recorder and associated playback transmitter. . . ."
Kraft said the tradeoff of weight and cost of a data recorder and dump transmitter versus possible loss of data for primary mission objectives, considering the cost of a Saturn IB launch vehicle, a fully functional LEM spacecraft, and the ground support required, seemed inequitable. He recommended that a data tape recorder and associated playback transmitter be installed on LEM-1 (and 2) to ensure that test objectives were achieved.
MSC ordered Grumman to propose a gaseous oxygen storage configuration for the LEM's environmental control system (ECS), including all oxygen requirements and system weights. Because no decision was yet made on simultaneous surface excursions by the crew, Grumman should design the LEM's ECS for either one-or two-man operations. And the Center further defined requirements for cabin repressurizations and replenishment of the portable life support systems. Oxygen quantities and pressures would be worked out on the basis of these ground rules.
Harry L. Reynolds, Assistant Manager of ASPO, said it was "becoming increasingly clear that we are going to have a difficult job keeping the LEM weight below the control weight." He said the Grumman effort was not adequate and suggested that R. Bullard of MSC be given LEM weight control as a full-time responsibility.
Owen E. Maynard, Chief of the Systems Engineering Division, vetoed a demand by the Flight Control Division for redundancy in the LEM's pulse code modulation telemetry system. Two factors determined Maynard's action:
Crew Systems Division (CSD) completed its study on the feasibility of controlling the amount of bacteria vented from the LEM. Division researchers found that, by placing special filters in the environmental control system (ECS) of the spacecraft, emission levels could be greatly lowered. This reduction would be meaningless, however, in view of effluents from the extravehicular mobility unit (EMU) - the moon would still be contaminated by the space travelers. Because of weight penalties - and because of their dubious value - CSD recommended that bacteria filters not be added to the LEM's ECS. The Division further advised that, at present, neither the amount of bacteria emitted from the EMU nor a means of controlling this effluence was yet known.
MSC directed Grumman to implement changes in weights of the LEM:
|Total LEM||14,515 kg (32,000 lbs)|
|Ascent stage inert||2,193 kg (4,835 lbs)|
|Descent stage inert||2,166 kg (4,775 lbs)|
MSC officially notified Grumman that, as part of the Apollo scientific program, an experiments package would be left on the moon by the crewmen of the LEM. The Center outlined weight and storage requirements for the package, which would be stored in the descent stage of the vehicle along with the lunar geological equipment. And MSC emphasized the need for dissipating waste heat given off by the system's radioisotope generator. (The radioisotope generator was a firm requirement, despite the fear voiced by many scientists that the radiation it gave off would disrupt the experiments.)
MSC rejected North American's second design concept for a panel retention system in the LEM adapter. (The contractor's first proposal had drawn an unsatisfactory verdict early in June.) These successive rejections, largely on the basis of weight and vibration factors, illustrated the company's continuing difficulties with the system. MSC "suggested" to North American that it circumvent these problems by attaching the retention cable directly to the skin of the adapter.
At a third status meeting on LEM-1, Grumman put into effect "Operation Scrape," an effort to lighten that spacecraft by about 57 kg (125 lbs). "Scrape" involved an exchange of parts between LEM-1 and LTA-3. The former vehicle thus would be heavier than the latter; LTA-3, on the other hand, would have the same structural weight as LEMs 2 and forthcoming.
Assistant ASPO Manager William A. Lee told the General Instrumentation Branch of the Instrumentation and Electronic Systems Division Grumman was preparing a proposal for use of the LEM vehicle as an electrical ground. The plan was to adopt a single wire system selectively for those circuits not susceptible to electrical transients. Lee said Grumman estimated a weight savings of 27 kg (60 lbs) in the ascent stage and 9 kg (20 lbs) in the descent stage. The proposal was expected to be available to NASA by October 1 and Lee had committed NASA to a decision within three weeks of receipt of the plan.
Owen E. Maynard, Chief of Systems Engineering Division, advised ASPO Manager Joseph F. Shea of the major technical problems currently plaguing Apollo designers:
ASPO Manager Joseph F. Shea announced a new plan for controlling the weight of Apollo spacecraft. Every week, subsystem managers would report to a Weight Control Board (WCB), headed by Shea, which would rule on their proposals for meeting the target weight for their systems. Three task forces also would report to the WCB on the way to lighten the spacecraft:
The Assistant Chief for Electronic Systems notified ASPO that the proposed Grumman plan to repackage the LEM pulse command modulated and timing electronic assembly (PCMTEA) had been discussed and investigated and that the Instrumentation and Electronic Systems Division (IESD) concurred with the proposal.
Following is the impact to the PCMTEA as a result of Grumman's proposed changes:
The Instrumentation and Electronic Systems Division (IESD) proposed that the LEM's inflight VHF antenna might be used as a link to astronauts on the surface of the moon as well. (LEM communications had to provide VHF contact with the crew outside the spacecraft at ranges up to three nautical miles. The VHF antenna, however, had been designed only for the flight portions of the mission, and to meet this communications requirement another antenna was being added to the LEM at a cost of between 1.36 and 2.26 kg [3 and 5 lbs].) IESD offered to study the coverage and range of the inflight antenna while on the lunar surface, and suggested that the three-mile range requirement might be relaxed. The additional VHF antenna might thereby be obviated.
Also, IESD attended a preliminary design review at Autonetics on the signal conditioning equipment (SCE) for the Block II CSM. IESD concurred in several modifications to the Block I design (adding a redundant power supply; hermetic sealing of equipment; and repackaging to fit the equipment bay in Block II CMs). These changes reduced the SCE's weight from 22 to 19 kg (47.5 to 41 lbs) and, because of more efficient power supply, lowered its power consumption from 65 to 35 watts. North American was studying ways of perhaps lightening the SCE even further.
To ensure compatibility with the spacecraft, MSC specified weight and storage details for the extravehicular visors. The devices, two of which would be carried on each mission and transferred from the CM to the LEM, would afford impact, thermal, and ultraviolet protection for the crew during operations in space or on the lunar surface.
Apollo Program Director Samuel C. Phillips said the Apollo Weight and Performance management system, jointly developed by the Apollo Program Office and the Centers had proved itself as a useful management tool. He considered that the system had matured to the point that changes in organizational responsibility were needed. He set a target date of December 31, 1965, to complete the following actions:
Phillips told ASPO Manager Joseph F. Shea that if he wished to continue to use GE's service in this area, he would support his request with the stipulation that GE's prediction analysis operation be supervised by MSC personnel.
The MSC Systems Development Branch rejected a proposal that the Development Flight Instrumentation (DFI) on LEM-3 be deleted for the following reasons:
ASPO Manager Joseph F. Shea reported to Apollo Program Director Samuel C. Phillips on changes in spacecraft weights:
NASA Hq. requested the MSC Apollo Spacecraft Program Office to reassess the spacecraft control weights and delta-V budget and prepare recommendations for the first lunar landing mission weight and performance budgets. The ASPO spacecraft Weight Report for April indicated that the Block II CSM, when loaded for an 8.3-day mission, would exceed its control weights by more than 180 kilograms and the projected value would exceed the control weight by more than 630 kilograms. At the same time the LEM was reported at 495 kilograms under its control weight. Credit for LEM weight reduction had been attributed to Grumman's Super Weight Improvement Program.
The Bethpage RASPO Business Manager and Grumman representatives met to choose a vendor to produce the orbital rate drive electronics for Apollo and LM (ORDEAL). Three proposals were received: Arma Division of American Bosch Arma Corp., $275,000; Kearfott Products Division of General Precision, Inc., $295,000; and Bendix Corp., $715,000. Kearfott's proposal was evaluated as offering a more desirable weight, more certain delivery, and smaller size within the power budget and consequently was selected although it was not the low bid. Evaluators believed that Arma's approach would not be easy to implement, that its delivery schedule was unrealistic, and that its proposal lacked a definite work statement in the areas of testing, quality control, reliability, and documentation.
An MSC meeting selected a Flight Operations Directorate position on basic factors of the first lunar landing mission phase and initiated a plan by which the Directorate would inform other organizations of the factors and the operational capabilities of combining them into alternate lunar surface mission plans.
Flight Operations Director Christopher C. Kraft, Jr., conducted the discussion, with Rodney G. Rose, Carl Kovitz, Morris V. Jenkins, William E. Platt, James E. Hannigan, Bruce H. Walton, and William L. Davidson participating.
The major factors (philosophy) identified at the meeting were:
NASA Associate Administrator for Manned Space Flight George E. Mueller stated that the February completion of MSFC studies of the Saturn V launch vehicle's payload and structural capability would permit an official revision of the payload from 43,100 kilograms to 44,500 kilograms; the CM weight would be revised from 5,000 to 5,400 kilograms; and the LM from 13,600 to 14,500.
A meeting at MSC discussed CSM and LM changes, schedules, and related test and hardware programs. On June 26, NASA Apollo Program Manager Samuel C. Phillips summarized the discussion in a letter to George Low. He pointed out that certain problems could result in serious program impact if not solved expeditiously and specifically mentioned couch design, the weight problem in the CSM and LM, docking changes, and delivery schedules.
Bendix Corp. demonstrated the operation of a sliding boom concept to prove that the Apollo Lunar Surface Experiments Package (ALSEP) could be removed from the LM at various attitudes. MSC representatives viewing the demonstration at Ann Arbor, Mich., were Aaron Cohen, Don Weissman, Paul Gerke, Don Lind, and Harrison Schmitt. Cohen reported that the mockup was crude but indicated that the concept was satisfactory to both Grumman and NASAL Design refinement, qualification, and effect on LM structure would have to be looked into. It was believed an additional seven kilograms of weight would be added to the LM descent stage. Two interface problems were defined at the meeting:
In a memorandum to the Chief, Systems Engineering Division, MSC, ASPO Manager George M. Low pointed out the weight problem in the CSM and LM was critical. Low called for a detailed review of weight effects along with any proposed design change. The weight estimate was to be submitted by the affected contractor as a part of his change proposal, and this would then be verified by the subsystems manager and Systems Engineering.
To provide timely weight status to the Configuration Control Board, Systems Engineering Division was given the responsibility of presenting CSM and LM weight status at each weekly Board meeting as follows:
Leonard Reiffel of the NASA Hq. Apollo Program Office suggested to Program Director Samuel C. Phillips that "we do not schedule the ALSEP [Apollo Lunar Surface Experiments Package] for the first lunar landing," because:
He added, "An uncrowded time line on the lunar surface for the first mission would seem to me more contributory to the advance of science than trying to do so much on the first mission that we do nothing well. . . ."
An exchange of correspondence between MSC and North American Rockwell emphasized the seriousness of the spacecraft weight problem. Accurate and timely weight visibility was of paramount importance for weight control and resulted from proper implementation and control of weight prediction, weight control from design initiation, and weight status reporting. To ensure visibility, North American Rockwell was instituting a program that would use system design personnel in weight prediction and reporting. Preliminary design personnel in the Design Requirements Group were designated to integrate the effort.
Actions on television cameras were reported by ASPO Manager George M. Low to Apollo Program Director Samuel C. Phillips:
Astronaut Charles (Pete) Conrad's concern about an anticipated attitude control problem in the LM was reported. Conrad had said, "The LM is too sporty when in a light weight configuration." Minimum impulse was expected to produce about 0.3 degree per second rate, which was estimated to be about four times too fast. A memo on the problem possibility was written by Howard W. Tindall, Jr., Deputy Chief of MSC's Mission Planning and Analysis Division, to stimulate thinking. On December 9, ASPO Manager George M. Low asked Donald K. Slayton and Warren J. North if there was any chance of setting up a simulation to see whether this was a real concern.
A Lunar Mission Planning Board meeting was held at MSC with Julian M. West as acting chairman. Also present were Wilmot N. Hess, Christopher C. Kraft, Jr., Paul E. Purser, and Andre J. Meyer, Jr. (secretary); and invited participants Gus R. Babb, John M. Eggleston, and James J. Taylor. The meeting agenda involved two main subjects:
Hess, MSC Director of Science and Applications, reviewed the Group for Lunar Exploration Planning (GLEP) meeting in Washington December 8 and 9, which had examined potential sites for lunar exploration beyond Apollo based on scientific objectives and not operational considerations. He pointed out that during the GLEP group study at Santa Cruz, Calif., in the summer, scientists had strongly recommended a manned orbital mission be flown before manned landings, to gain additional photographic information for more effective mission planning and to make remote-sensing measurements to detect anomalies on the lunar surface. Hess said this position had changed to some extent.
Hess pointed out that lunar exploration was the responsibility of the new Lunar Exploration Office at NASA Hq. The office had further been subdivided into the Lunar Science Office, responsible for science and experiment planning, and the Flight Systems Office, responsible for modifications in the Apollo spacecraft to increase capability for developing advanced support systems such as mobility units and for developing the advanced ALSEP packages. Hess felt that dual launches, if conducted at all, would be carried out in the far distant future and therefore directed his group to select sites for nine single-launch missions, three of which should be planned without the aid of mobility and be limited to one-and-a-half kilometers; and the other six sites limited to five-kilometer maximum mobility radius.
Ground rules used in reduction of the proposed 39 lunar exploration sites were:
Apollo Program Director Samuel C. Phillips wrote ASPO Manager George M. Low requesting that he establish and maintain a detailed comparison of configuration differences between the CSM and LM. This comparison, Phillips said, should include major interface differences, subsystems and components, weight, performance, and crew safety. Phillips ordered this comparison chiefly because the Apollo spacecraft was entering an extremely important phase to certify the vehicles for manned flight.
Joseph G. Gavin, Jr., LM Program Director at Grumman, advised ASPO Manager George M. Low of steps under way to attack the problem of stress corrosion in the LM. (Low had expressed MSC's concern over this potential danger on December 20, 1967.) While stating that he shared Low's concern, Gavin believed that stress corrosion would not prove to be of significance to the LM mission. However, his organization was prepared to reevaluate the LM's design and fabrication to determine to what extent the problem could be ameliorated. (Gavin denied that such metal corrosion could be absolutely eliminated using present materials as dictated by weight constraints on the LM design.) Gavin stated that he had created a special team of experienced designers and stress analysts to review engineering design of every LM part sensitive to stress corrosion, to review processes employed in fabrication of the LM structure, and to review the adequacy of the company's quality control procedures to ensure corrosion-free parts and assemblies.
ASPO Manager George M. Low asked Joseph N. Kotanchik, head of the Structures and Mechanics Division, to verify that all spacecraft load analyses and safety factors were compatible with the recently agreed-on payload weight of 39,780 kilograms for the AS-503 mission. Low passed along the concern voiced by Lee B. James, Saturn V Program Manager at MSFC, that the problem of an S-IC engine failure in the Saturn launch vehicle might be more severe for the 503 mission than for a heavier payload. Had adequate stress analysis been done on the high-gain antenna attachments and its support inside the adapter? When would pogo dynamic analysis of the actual 503 payload be completed? And finally, what was the situation regarding loads on LTA-B, the LM test article to be substituted in place of an actual lunar lander aboard the flight?
George M. Low, ASPO Manager, set forth the rationale for using LTA-B (as opposed to some other LM test article or even a full-blown LM) as payload ballast on the AS-503 mission. That decision had been a joint one by Headquarters, MSFC, and MSC. Perhaps the chief reason for the decision was Marshall's position that the Saturn V's control system was extremely sensitive to payload weight. Numerous tests had been made for payloads of around 38,555 kilograms but none for those in the 29,435- to 31,750-kilogram range. MSFC had therefore asked that the minimum payload for AS-503 be set at 38,555 kilograms. Because LTA-B brought the total payload weight to 39,780 kilograms, that vehicle had been selected for the Apollo 8 mission. All dynamic analyses in connection with the pogo problem had to be verified, but MSFC engineers were not concerned that the established weight would affect pogo performance. Because NASA had been prepared to fly AS-503 with a heavier payload - i.e., originally including LM-3 - Low saw "no reason to be concerned about the decision made to fly the somewhat lighter and more symmetrical LTA-B."
Ralph H. Tripp, LM Program Manager at Grumman, forwarded his company's plan for control of configuration changes on the LM. The need for such a formal statement had been discussed at a meeting in Bethpage on September 25 between ASPO Manager George M. Low; his deputy for the LM, C. H. Bolender; other Apollo engineers from Houston; and Tripp, LM Program Director Joseph G. Gavin, Jr., and others from Grumman. Grumman's ground rules set forth explicit guidelines governing change approval levels, specifically those changes which the contractor might make without obtaining prior specific approval from NASA (defined as "compatibility changes" that did not have significant cost, weight, performance, schedule, or safety effects) - although Grumman must continue to inform MSC of these changes as they occurred.
LeRoy E. Day, Apollo Test Director, NASA Hq., informed Apollo Program Director Samuel C. Phillips of two failures of LM propellant tanks during testing, a problem that might have significant program impact on LMs 6 and 7 and subsequent vehicles. The particular tanks in question were those manufactured by Allison Division of General Motors but reworked under separate contract by Airite Division of Sargent Industries. The two tanks, lightweight SWIP II models slated for LM-6 and subsequent vehicles, had suffered small cracks in the welds. So far, said Day, the weld process used in manufacture of the tanks was "highly suspect." Cryogenic proof-testing probably would be required to validate the tanks and to give confidence in the tank welds. Meantime, he said, the problem was receiving high-level attention both at Grumman and in Houston.
ASPO Manager George Low informed MSC Director of Science and Applications Wilmot N. Hess that he had signed paperwork increasing the weight allowance for the Apollo scientific payload from 136 to 156.4 kilograms. Low said he was able to do this for the LM-6 (Apollo 12) mission because of the favorable LM weight picture. He stated, however, "I believe that we should understand that this increase in weight allowance does not alter our basic agreement to provide for a scientific payload of 300 pounds [136 kilograms]. In the event that future difficulties with the Lunar Module require additional weight growth in the basic spacecraft system, we will have to once again reduce the scientific payload to 300 pounds [136 kilograms]. . . . I wanted to be sure that we agreed in advance that the added 45 pounds [20.4 kilograms] of scientific payload allowance would be the first weight to be deleted. . . ." Hess concurred with the memorandum.
The MSC Flight Crew Operations Directorate submitted its requirement for a simple lightweight Rover (lunar roving vehicle) guidance and navigation system that would provide the following displayed information to the crew: vehicle heading and heading to the LM, speed in kilometers per hour, total distance traveled in kilometers, and distance to the LM. Requirements were based on the assumptions that the landing area was as well known as for Apollo 12, all traverses were preplanned, accurate photo maps were available, and there was MSFN support through voice communications. The Directorate emphasized that it had no requirements for a display of pitch and roll, X and Y coordinates, or time.
An Olympic Games flag 1.2 by 1.8 meters would be packed in a fireproof container and carried in the command module during the Apollo 16 mission. Weight and storage limitations would preclude carrying the flag in the lunar module. However, an additional Olympic Games flag, 1.2 by 1.8 centimeters, would be carried in the LM flag kit to the lunar surface. Small flags of members of the United Nations, other international organizations, and national states generally accepted as independent in the world community would be carried on the mission in the LM flag kit.