Moon Lander: How We Developed the Apollo Lunar Module (23 page)

Shortly after Rector’s request for more vigorous and effective weight reduction by Grumman, Arnold Whitaker presented a plan for tightening control
on subcontractor and vendor equipment weights. He recommended that we include the allowable weight-change limit as part of every change request that Grumman issued to its suppliers and require the subcontractor to estimate the weight impact as part of his change proposal. This would be followed up by specific accounting of the actual weight impact of the change. The subcontractor’s weight-control performance would be a factor considered in determining his incentive fee. Gavin and Mullaney promptly implemented Whitaker’s suggestion.
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However, as the reports came in from this tightened control over the subcontractors, it was clear that LM again was increasing in weight. By July 1965 we were reporting LM as exceeding the control weight of thirty-two thousand pounds.

Rathke and I decided that an all-out “crash” effort was needed to reduce LM weight and to control further growth, despite the disruption this might cause to our equally critical drive to meet drawing-release schedules. We initiated a “scrape” program, led by Sal Salina, head of the Weight Control Section, Len Paulsrud, head of Vehicle Design, and Dick Hilderman, head of Structural Analysis, to whittle weight from the LM structure. By making more extensive use of chemical milling, precision machining, and material substitutions, we could obtain significant weight reductions without major changes in the structural arrangement of LM. Unfortunately, this was not enough for the twenty-five hundred to three thousand pounds of reduction we needed as a margin against further growth.

From Grant Hedrick we learned of a successful approach Grumman recently used on the Fin aircraft program that we could apply to LM. Grumman was a major subcontractor to General Dynamics, supplying the aft fuselage and tail assemblies for all Fins and the design and final assembly of the navy version of this joint air force-navy airplane. General Dynamics-Grumman had won the Fin contract within weeks after the LM award. Despite a very extensive pre-award preliminary design and mockup, as the detailed design proceeded, both the air force and navy versions outgrew their weight limits and engine capabilities. To save the Fin program, which was threatened with cancellation if its weight and performance goals were not met, General Dynamics-Grumman mounted a drastic response, called the Super Weight Improvement Program, or SWIP. Even though most of the airplane and system designs had been completed and released to manufacturing, an independent team of SWIP design experts was turned loose on the program to second guess every aspect of the design for weight savings. The SWIP team worked cooperatively with project Engineering, but they had a direct reporting channel to the Fin program manager to assure that none of their recommendations would be stifled. A dollars-per-pound criterion was established to set a threshold for accepting weight reductions; for the Fin it was five hundred dollars per pound. SWIP was successful on the Fin: weight growth stopped and there was some net reduction in weight. The cost of the changes
was high but affordable, and the resulting impacts on the schedule could be endured. SWIP saved the Fin program.

Early in 1966 Roy Grumman retired as chairman of the board and was replaced by Clint Towl. Llewllyn J. “Lew” Evans was then appointed president of Grumman Aerospace Corporation. Lew was a lawyer who came to Grumman as chief counsel after working in the Legal Department. He had a flair for marketing and deal making and became vice president of Business Development, strengthening and expanding Grumman’s close working relations with the navy. A charismatic and inspiring leader, Lew lost no time in getting acquainted with Grumman’s newest major customer, NASA. He held internal reviews on the status of the LM program and was alarmed by the array of problems he found involving our technical, schedule, and cost performance. To provide direct corporate-level oversight of the program, he established the Executive and Technical Review Board (ETRB), chaired by Senior Vice President George Titterton. At its first meeting the ETRB urged Gavin to conduct a SWIP on LM and offered to make available the SWIP review team, which was then finishing its work on the F111.

In July 1965 I was put in charge of the LM SWIP activity. The Grumman SWIP review team, twelve engineers headed by Ed Tobin and his deputy, Paul Wiedenhaefer, would report to me for the duration of the exercise. They had unlimited access throughout the program and a direct reporting channel to Grant Hedrick. NASA management liked the plan; they were pleased that Grumman was taking forceful action to control weight. Bill Lee was assigned by Joe Shea to be my counterpart as co-chair of the SWIP team.

Anyone could make weight-reduction suggestions to the SWIP team; opinions were actively sought through the employee suggestion program. Grumman was responsible for evaluating SWIP items and making recommendations to NASA for approval. We held intensive weekly reviews with NASA, usually at Bethpage, which Bill Lee always attended, often accompanied by Maynard, Johnson, and other engineers. Internally the SWIP team met several times a week with LM Engineering and Manufacturing management, reviewing hundreds of SWIP weight-reduction items and suggestions and thousands of Grumman and subcontractor drawings. Each item was evaluated and dispositioned against the criterion, which after considerable study and discussion had been set at ten thousand dollars per pound for “round-trip” items. Not every SWIP item could make it in time for LM-1; some of the more difficult items were phased in at LM-3, LM-4, or even LM-5. Even so the disruption to the schedule was severe and required constant replanning and revision of the PERT networks and schedules as we fought to maintain forward motion on the program while accommodating some major design changes to save weight.

Tobin and Wiedenhaefer were thorough, persistent, and innovative in finding areas to reduce weight. They were curious about how every system
worked on LM and how the critical loads, safety factors, and materials choices were arrived at, so they led us through a complete review and justification of the LM design criteria and choices. Some LM engineers bristled at being second-guessed on their designs, but Ed and Paul were so logical in their questions and approach that no one could take offense. At their suggestion, we began holding SWIP meetings at our major subcontractors’ facilities, too, as more than half our SWIP items were in subcontractors’ equipment.

Although the SWIP team worked full time implementing the weight-reduction effort, I supplied the technical leadership and made the decisions for Grumman. Joe Shea, Joe Gavin, and I kicked off the SWIP effort at a motivational meeting with a large audience in the Plant 25 main conference room, making clear that the future of the Apollo program could very well depend upon the success of our efforts. We introduced Tobin and Wiedenhaefer to the LM people, and they told briefly what they had done on the Fin program and how successful it had been. They were confident of being able to do it again for LM. I made clear that all LM Engineering managers would be heavily involved and would be accountable for delivering their portion of the required weight savings. In the active question and answer session that followed, our engineers clearly showed their desire to support this program but expressed reasonable concerns and asked for direction in how to balance conflicting priorities in their workloads. We promised to expand the SWIP guidelines beyond the dollars-per-pound criterion to include schedule and reliability criteria also.

My daily technical staff meetings and weekly SWIP meeting were the management focus of the effort. The SWIP meeting usually took three or four hours. Tobin and Wiedenhaefer went through the list of potential SWIP items, noting new additions and reviewing the status of each. Whenever an item was ready for decision, whether to implement, modify, or delete, the SWIP team would be joined by the “cognizant” LM subsystem engineer (called the “cog engineer”) or section head.
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Bob Carbee attended all SWIP meetings, contributing to the decisions and following up in implementing them in his subsystem design groups. At the technical staff meetings the SWIP team usually was not present, but we examined in detail the design issues involved in one or two SWIP items in the subsystem under discussion.

We started the SWIP effort by establishing target weights for each subsystem, broken down into all its parts and components. These were arrived at in reviews with the cognizant subsystem engineer, his Engineering section head, and representatives from his principal subcontractor and suppliers. Drawings and specifications for the subsystem and its major components were reexamined and avenues of possible weight reduction identified. Because most of the designs had been released to manufacturing and many of the system components had been through some amount of development testing, we also discussed the potential impact on schedule and cost of these changes. The outcome
of these meetings was that the cog engineer, his section head, and his subcontractor accepted a weight-reduction “target to beat” for SWIP.

I concentrated on the “big-ticket” items that had major potential for weight reduction, although no item was too small to escape the fine net trolled by the SWIP team (items down to .1 pound were considered). Structure headed the big-ticket items because there was so much of it. Redesign, scrape, and materials substitutions were possible in virtually all parts of the LM structure, and thanks to the inspired and diligent efforts of the Vehicle Design Section we saved every possible ounce. The Materials Section played a key role in identifying substitute lightweight materials and in perfecting the chem-milling process in Manufacturing, which was a major technique for reducing the weight of structural parts.

Implementing supercritical helium pressurization of the descent propellant tanks was another big weight saver. Feasibility of this item depended upon the design ingenuity of the LM Propulsion Section and their cryogenic tank subcontractor, Airesearch Division of Garrett Corporation, and by the Fluids GSE Section and their cryogenic tank and component supplier Beech Aircraft. Neither I nor NASA were willing to approve the supercritical helium change until we saw a design for the GSE that convinced us that it would be practical to load and unload this hard-to-handle material on the Apollo launch pad at Kennedy Space Center.

I also gave major attention to the substitution of batteries for fuel cells in the electrical power system. This change was made to improve reliability because the use of batteries eliminated a very complex system of hydrogen and oxygen tanks, plumbing, and components—as well as the fuel cells themselves. From a SWIP standpoint, I had to assure that minimum weight increase resulted. We had to be very sure of what we were doing, both in verifying the battery suppliers claims and accurately assessing the weight of the fuel cell system. Our fuel cell subcontractor, Pratt and Whitney, was well along in building and testing development units both for LM and the CSM, which used a similar system. Grumman held a competition between battery suppliers Eagle Picher and Yardney, and obtained electrical test results and actual weights from both of them. On 26 February 1965 Shea approved the change to Eagle Picher batteries for LM.
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The environmental control subsystem was a considerable source of weight savings. With the cooperation of its subcontractor, Hamilton Standard, the ECS Section was able to wring dozens of pounds out of this vital and complex subsystem. After studying many possible configurations, changes to the oxygen-supply section were adopted that optimized it for minimum weight. Cryogenic storage of liquid oxygen was investigated, but we selected a simpler system with high-pressure (2,730 psia) storage of gaseous oxygen in the descent stage. Two much smaller low-pressure tanks in the ascent stage provided the oxygen needed from lunar liftoff to rendezvous. Additional
weight savings were gained by structural redesign in titanium of the truss assembly that housed and supported many of the ECS components located inside the LM cabin, and by shaving weight from the components themselves.

As the LM weight concerns intensified, pressure grew to reduce the layers of functional redundancy that provided LM and CSM with lunar-orbit rendezvous capability. In 1964 the system had rendezvous radars on both LM and the service module, but in February 1965 the SM radar was deleted and an optical tracking light added to LM. Shortly thereafter, as a result of the study we recommended in our November 1964 weight-reduction response, Cline W. Frasier of NASA suggested replacing the rendezvous radar in LM with an optical system as well. Consisting of a star tracker in the LM, a xenon strobe light on the SM, and a hand-held sextant for the LM pilot, the optical system claimed reductions of ninety pounds and $30 million.
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We were directed to make the LM compatible with an optical rendezvous system, and in August 1965 AC Electronics was chosen to develop the optical tracking light.

Late in the year, Mueller, Shea, and Robert C. Duncan set up what they called a “rendezvous sensor Olympics” to be completed in the spring of 1966. The intent was to conduct laboratory demonstrations of the RCA rendezvous radar and the optical system and compare the performance capabilities of each. Before the Olympics even started the astronaut office indicated a strong preference for the radar because it was more flexible and self-contained. The radar directly provided the critical rendezvous parameters of range (distance to the target) and range rate (velocity of closure with the target), while the optical system derived range from the VHF (very high frequency) communications system and did not provide instantaneous range rate.
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In June 1966, after tests and presentations by competing contractors RCA and Hughes Aircraft Company, Grumman recommended that the RCA rendezvous radar be retained and the LM-active optical system dropped. NASA’s Sensor Olympics Review Board agreed with the radar choice. The optical system no longer offered cost savings over the radar; as its development proceeded the optical system’s cost estimates had grown to approximately equal the radar’s. The optical system was still lighter, but by mid-1966 the SWIP effort had been so successful that this one item was no longer crucial. NASA’s decision was strongly influenced by the adamant position in favor of the radar taken by astronauts Slayton and Schweickart. Gemini rendezvous flights had been successful using rendezvous radar yielding on-board range and range rate, and the astronauts argued that Apollo should build directly upon these recently demonstrated experiences and procedures.