Moon Lander: How We Developed the Apollo Lunar Module (22 page)

Hedrick was right, and his astute observations put NASA on the path to a proper analysis. Later he would apply his unique talents to the solution of some of LM’s most difficult technical problems.

The involvement of Meyer and Titterton was sometimes less beneficial. Meyer was generous in making available talented Flight Test managers to the LM program. These men had valuable experience in real-time scheduling and dealing with unanticipated problems while conducting challenging test programs. But Meyer’s generosity sometimes came with a string attached. He maintained “back-door” communication with some of his former people on LM and sometimes used this to his own ends with corporate management, as when he mounted an internal campaign to remove the checkout and test responsibility from the LM program and assign it to the Flight Test Department.

George Titterton’s contributions also had pluses and minuses. On the plus side, he had the internal clout to get the LM program what it needed, in budgets, people, facilities, and equipment. When convinced, he moved swiftly and effectively to place added resources at our disposal. This was extremely valuable during the buildup years of 1965 and 1966. He was also a hard-driving, ramrod manager who set high standards and accepted no excuses, and he quickly developed a close rapport with Joe Shea because in this regard they were soul mates.

NASA officials view the lunar module mockup at Bethpage.
Left to right:
Joe Shea, Tom Kelly, Bob Gilruth, and Joe Gavin. (Courtesy Northrop/Grumman Corporation) (
Illustration credit 7.1
)

On the minus side, Titterton’s personal management style could be divisive and confrontational. His established method was to pit the Engineering, Manufacturing, and Flight Test Departments against one another, showering all sides with heavy doses of sarcasm and ridicule. Outside of work he was engaging, witty, and considerate, a perfect gentleman, but when exercising his command authority on the job before an audience he could be a difficult man.

Tom Kelly in his Bethpage office, 1965. (Courtesy Northrop/Grumman Corporation) (
Illustration credit 7.2
)

Titterton enjoyed being the champion of the long-suffering shop workers who were continually misled and frustrated by the out-of-touch ivory tower engineers (“knuckleheads,” he called them). I tried to counteract his attitude because I believed that open, honest cooperation and teamwork between Engineering and Manufacturing was our only hope of reaching our goals.

By early 1966 LM drawing production had hit its stride; on 18 April I noted that 556 drawings had been released in the prior week, 356 of which were for the flight vehicles and 200 for GSE.
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We were finally making our schedules, but it had been a long struggle, more than a year and a half, and we were now faced with a new challenge: getting the LMs through final assembly and test. This would require the development and validation of several hundred test plans and operational checkout procedures (OCPs), documenting every detail of the tests so they could be programmed into the ACE stations and witnessed by Grumman and NASA Quality Control. No sooner did we reach the required high plateau in drawing output than another mountain to climb loomed in the near distance.

Just Another Job?

Under such a continuous grind, program excitement wore thin. LM was becoming more like a job, with such high pressure that it exacted a high toll from its participants. We had almost succeeded in taking the fun out of building a spacecraft to take men to the Moon. But not quite. Every month the full Moon reminded me of the scope of our grand endeavor and made all the pressure, deadlines, schedule commitments, and management in-fighting worthwhile. I could withstand Shea’s wrath and Titterton’s ridicule because I knew that when our LM landed the first astronauts on the Moon’s pristine surface, these travails would count for nothing. Perhaps like childbirth, the pain would be forgotten in the glory of a new beginning.

I was insulated from any thought that we might not be successful. By reducing the LM program to thousands of PERT “inchstones”—minor events that could be scheduled and verified when they happened—we had removed any doubt that the conclusion would not be successful. By following the “
yellow
brick road” of our PERT networks, we were sure to reach the Moon. The only question was when, and would I still be on the program with my reputation intact when we got there?

8

Trimming Pounds and Ounces

Even before Grumman was placed under contract the weight of the LM had grown, and as we began the actual design of the craft, its weight continued to increase at an alarming rate. Our LM proposal design was estimated at 22,000 pounds, but in discussions with NASA at the contract negotiations it was agreed to increase LM’s weight to 25,000 pounds. The target weight, which was used for propellant-tank sizing, was increased to 29,500 pounds in February 1964. This was the basis for the tank sizes in the TM-1 and M-5 mockups. The estimated weight of the design soon exceeded the target, and we again faced the need to increase the target weight and the size of LM’s propellant tanks.

Because of the flight mechanics and rocket propulsion constants of the lunar mission, LM was extremely sensitive to weight growth. For every pound in the ascent stage, three pounds of propellant were required to land it on the Moon’s surface from lunar orbit, lift it back into lunar orbit, and rendezvous with the CSM. The weight growth factor was, therefore, 4 to 1: every pound of added ascent-stage inert weight increased the Earth launch weight of the LM by four pounds. Weight added to the descent stage but left on the Moon had a growth factor of 2.25 to 1. This was far greater than for aircraft, even for military missions with fighters and attack bombers, where growth factors seldom exceeded 15 percent, or 1.15 to 1.

The major factors that drove LM weight up during 1963 and 1964 were reliability requirements, mission operational requirements, and configuration definition. The reliability approach that we had adopted relied upon functional or component redundancy and ample safety factors where redundancy was not possible. This was a sound design philosophy, but it added weight compared to our proposal design, which had little redundancy.

Operational requirements became visible to us through the work of the Apollo Mission Planning Task Force. Their design reference mission provided
the basis for estimating many operational requirements that affected LM weight: the duty cycle (on/off times) of LM equipment requiring electrical power, the number of cabin pressurizations with oxygen, the spacecraft attitude relative to the Sun and hence heat loads and cooling water capacity, the amount of consumables (water, oxygen, power, propellants) required on LM, and so on. There was a wealth of data in the DRM that had an effect on weight. As we dug into this, our understanding of mission operations requirements improved and the weight grew.

Configuration definition changed swiftly in 1963, when the ascent stage’s geometry was completely revised in the M-1 mockup. A year later the M-5 mockup essentially completed the definition of LM’s basic configuration. The weight estimates were revised based on this geometry and equipment arrangement, and invariably they were greater than before.

An empirical explanation for the large early weight growth on LM lies in the historical data accumulated on many aircraft and spacecraft programs, which shows that estimated weight, from design sketches and system descriptions, is typically 20 to 25 percent lower than weight in the final product, mainly due to the omission of many components and design details that are unknown to the estimators. Calculated weight, from engineering drawings, is usually 5 to 10 percent low because many small details, such as the exact number of fasteners, cut-outs, and installed components, are only approximated in the calculations. Not until actual weight is obtained by putting the various parts and assemblies on a scale is the bias toward low estimates corrected. As the LM design moved from sketches to drawings to fabricated parts, the weight increased with the increasing percentage of calculated and actual weights versus estimated.

No matter how we rationalized it, the inexorable growth in LM weight was threatening the whole Apollo mission. Caldwell Johnson was concerned that LM might become too heavy to do its job. Johnson’s opinion was not to be taken lightly. He had designed the Space Task Group’s own versions of the LM and constantly reviewed and critiqued Grumman’s emerging design, looking for improvements, simplifications, and weight savings. I obtained sound guidance from him, Maynard, and Faget in evaluating LM design choices.

In mid-October 1964 Carbee, Whitaker, and I had a lengthy meeting with Owen Maynard, Caldwell Johnson, and William A. Lee of the Apollo Operations Planning Division in NASA-Houston to review the LM’s weight status and tank resizing options. The NASA people had done their own analyses of LM’s weight growth history and status and found the outlook bleak. They projected 12 to 15 percent growth in LM’s weight from its then-estimated 30,200 pounds, which would exceed the maximum allocation for LM based upon a Saturn 5 boost capability of 32,000 pounds. They suggested possible LM design changes to reduce weight and modifications to the mission rules
and trajectories that might allow for an increase in the fraction of the Saturn 5 payload weight allocated to LM.
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We had a month to study these suggestions and add to them, and to recommend a target weight for LM resizing and an improved weight-control approach.

We responded that LM should be resized to a target weight of 32,000 pounds at Earth launch, of which 10,800 pounds would be in the ascent stage. This fully utilized the allocated Saturn 5 payload for LM. We also recommended a number of weight-reduction items, including the use of supercritical helium instead of gaseous helium to pressurize the descent propellant tanks, reduction of LM hover time at landing from two minutes to one, and possible use of batteries instead of fuel cells for electrical power. Batteries might not save weight, but they promised great simplification of the electrical power system and increased reliability. We urged further study of this option. Also recommended for study was replacement of the LM rendezvous radar with star trackers or lasers. Mission changes that we suggested NASA consider included use of a non-free return trajectory to the Moon and reduction of the CSM’s midcourse correction propellant allowance, both of which would allow more of the Saturn 5 payload to go to LM. After extensive discussions, these recommendations were approved by Maynard, Lee, and Johnson, then, the next day, by Joe Shea. Shea made clear to me that this was all the weight allowance they had to give LM, and that I had better get control of the weight growth or the whole program would be in deep trouble.
²

Rathke and I preached reduction and control at all our Engineering meetings and set up a system to identify and evaluate potential weight-reduction items. We devoted more time at the daily technical staff meetings to reviewing and deciding whether to incorporate these changes into the design, subject to approval by NASA and the Change Control Board. Still, the monthly LM weight-status report showed increases, and Grumman and NASA managements grew restive. Some of the largest increases were in equipment supplied by our subcontractors and vendors. In March 1965 Bill Rector met with me and strongly urged Grumman to set up an intensive weight-reduction effort, with emphasis on subcontractors and with continuous involvement with and direction by Grumman’s LM program office.
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Outside events overcame my single-minded dedication to LM: on 27 March 1965 Joan gave birth to a beautiful eight-pound baby boy. He was our fifth son and sixth child, and we named him Peter. I took two days off to mind our other children and take Joan and Peter home from the hospital. Not without pangs of conscience, because I was in the middle of finalizing the design of the newly adopted battery EPS and also the accelerating weight-reduction and drawing-schedule efforts. I soon disappeared into the vortex of work but I took my turn with middle-of-the-night baby feedings.