Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 hen President John F. Kennedy designs were sometimes risky, but always well thought

announced in May 1961 his goal to send a man to the out and, on occasion, elegantly simple. Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 moon, the United States had accomplished exactly 15 This month we celebrate the 40th anniversary of the minutes of human spaceflight time, Alan Shepard's sub­ achievement of President Kennedy's bold goal-Apollo orbital flight in the Mercury space capsule, Freedom 7. In 11's historic landing on the moon. And while most of the the run-up to that success, the American space program commemorations will feature Armstrong and Aldrin, had absorbed a series of high-profile embarrassments as who went to the moon, it took the efforts of Houbolt, the Soviet Union, with which the U.S. was competing Mueller, Castenholz, McClure, Kelly, Rathke, Carbee, in a so-called Space Race, seemed to remain one step Rigsby, Harms, Sherman, Bales, Garman, and thousands ahead. To declare so publicly the goal to land a man on of engineers just like them to make it possible. the moon before the end of the decade was to risk anoth­ Speaking as an engineer, it is impossible not to be in awe er humbling loss. of what they accomplished in just eight years. 1'd like to "We choose to go to the moon in this decade and do the share a few stories about their remarkable achievements. other things," Kennedy said in a speech at Rice Univer­ sity in September 1962, "not because they are easy, but because they are hard." And it was hard. The motive for Immediately following Kennedy's announcement, the President's goal may have been politics and prestige NASA managers asked themselves, "How do you get during the Cold War, but America's political fortunes were to the moon?" It wasn't the first time that engineers now in the hands of its top engineers. At the moment of had speculated on the problem: In the early 1950s, for Kennedy's announcement, the technology, the infrastruc­ instance, Collier's magazine had published a famous series ture, the hardware, and the technical workforce needed to of articles by leading scientists and engineers detailing a achieve this goal did not yet exist. plan to send men to the moon and Mars. But suddenly At the time, the public spotlight shined on the face of the question had turned from being an academic exercise the space program, the astronauts who had already become national heroes. What most people didn't realize was the massive harness­ ing of America's technological resources that occurred to make the moon landing possible. In all, more than 400,000 engineers, sci­ entists, and technicians working for more than 20,000 companies and universities contributed to Apollo's success. The engineers are not household names. Col­ lectively, however, they overcame ' enormous technological challeng- es with creativity, innovation, and persistence. Their decisions and

Burton Dicht is Managing Director of ASME"s Knowledge and Community Sector. His lifelong interest in aero­ space history has made him a fre­ quent lecturer at ASME"s sections and student sections. what he called "back of the envelope calculations." The results to Houbolt were irrefutable. LOR made it possible to use smaller and lighter spacecraft, thus mak­ ing the scale of the entire project simpler. But Houbolt could not convince his own bosses, and he did what most would consider career suicide by going around them directly to NASA's leaders in Washington. Houbolt's stubborn persistence in the face of great opposition and the validity of his engineering calcu­ lations finally won the day. NASA leadership slowly came around, and by the fall of 1962 it had adopted the LOR mission architecture. With the concept set, NASA

moved to develop the hardware necessary to make the Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 lunar flight.

The linchpin of the Apollo program was a launch vehicle powerful enough to propel the mother ship · and lunar landing craft to the moon. Without that crit­ ical piece, all other parts of the effort would be useless. Tackling the problem was the brilliant German-born rocket engineer Wernher von Braun and his team at the Marshall Spaceflight Center in Huntsville, Alabama. Their solution, the engineering masterpiece known as the. Saturn V, was a technological leap over anything the to a matter of national importance. United States had in its inventory at the time. One of the biggest issues to settle was the miSSion Consisting of three stages possessing more than 3 mil­ architecture-the steps through which spacecraft would lion parts in total, the Saturn V would tower some 363 be launched, landed on the moon, and returned safely. feet when fully stacked. As designed, the behemoth For instance, one potential mission architecture involved weighed more than 6 million pounds and its five F-1 launching a single manned vehicle directly to the moon engines would produce 7.5 million pounds of thrust. and returning the entire spacecraft to Earth. Although One day it would be the most powerful rocket ever straightforward, such a mission would be require launch­ launched. But in 1962 it was just a concept on a drawing ing a prohibitively large mass with a single rocket and board. O ver the next five years, von Braun and his team, was beyond the scope of what was possible in the 1960s. along with prime contractors Boeing, North American, Instead, the mission concept initially embraced by NASA Douglas, and Rocketdyne worked to design, manufac­ was called Earth Orbit Rendezvous. EOR involved the ture, and test the Saturn V. It was a massive engineering launch of two rockets with all of the components needed project that pushed the boundaries of the technology and for a lunar mission. In Earth orbit, the two rockets would manufacturing methods. rendezvous and dock, and then· the combined spacecraft In 1963, George Mueller, an engineering manager would continue onto the moon. This entire spacecraft from industry who had helped develop the Minuteman would land on the moon and return to Earth when the mission was completed. The other concept, l hich was not given much credence by the NASA hierarchy, was Lunar Orbit Rendezvous. In that mission architecture, a single launch vehicle would send a mother ship and a landing craft directly to the moon. In lunar orbit, the lander would separate from the mother ship and descend to the surface. On return the lunar lander would rendezvous and dock with the mother ship; the lander would then be discarded and the astro­ nauts would return to Earth in the mother ship. NASA's opposition to LOR centered on the complexity and danger associated with spacecraft that must rendezvous in lunar orbit. But John Houbolt, an engineer at NASA's Langley facility in Virginia, was a passionate advocate for LOR. Houbolt crunched the numbers for both concepts in

30 mechanical engineering I July 2009 Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 turer, worked overtime to deter­ mine the cause of the problem. The J-2 had never failed in any ground tests, and making a diagnosis of the problem next to impossible was the fact that the engineers did not have any hardware to examine. The only clue to work from was some telem­ etry data that pointed to a possible rupture of an auxiliary fuel line. Paul Castenholz, the J-2 project manager at Rocketdyne, led the investigation, and his team tested the engine again Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 , and again without failure. Frustrated, and with the weight of the entire Apollo program bear­ ing down on them, Castenholz and his engineers met to see if they were missing something. Marshall McClure, an engineer on the team, posed a simple question that would lead them down the path to an answer-"Would it be different in ballistic missile for the Air Force, was brought in as the space than on the ground?" associate administrator for manned space flight. Muel­ The engineers watched films of their tests and saw that ler conducted a top-to-bottom review of the Saturn V ice' was building up on the lines carrying super -cooled program and grew concerned over von Braun's testing liquid hydrogen and liquid oxygen. The fluid lines were plan. Von Braun was meticulous and proposed testing flexible and were susceptible to vibrations. Could the ice, the rocket's first stage by launching it with dummy upper which needed air to form, be protecting the lines during stages. If that flight succeeded, the tests would proceed ground tests? Castenholz and McClure used a special­ incrementally from there with dummy stages being ized test chamber to study the components under a vac­ replaced by live ones. Discounting the additional cost of uum and the fluid lines failed. A simple engineering fix manufacturing multiple test stages, Mueller questioned that involved adding steel mesh around the lines would the time it would take to conduct all of the launches von prevent future failures. The Saturn V was now ready to Braun proposed. NASA would never achieve the "end of carry astronauts. the decade" deadline set forth by Kennedy. Mueller instead pitched to von Braun what was called the "all up testing" concept: launching a fully assembled The Saturn V launch vehicle was just one of the Saturn V with all of the stages stacked and fueled. This necessary components needed for a Lunar Orbit was an approach Mueller used oh the Minuteman project Rendezvous-style mission. NASA also had to develop and while it was much riskier, it would enable the team a landing craft to take a pair of astronauts down to the to meet Kennedy's timetable. Mueller, using strong engi­ surface of the moon. The lander, known as the Lunar neering arguments, ultimately persuaded von Braun. Module, would serve as a shelter and base of operations The all up testing concept was put to its first test in on the lunar surface, and then launch the astronauts back November 1967 when the Saturn V made its debut into lunar orbit to rendezvous with the mother ship, the launch. Except for vibration problems (which would be Command/Service Module. corrected) the rocket performed so well that some test­ The responsibility for designing the LM fell to Thom­ ing instrumentation was removed for the second flight as Kelly and his team of engineers at Grumman Avia­ in April 1968. tion (now Northrop Grumman). Designing a spacecraft That test, designated Apollo 6, did not go well. The for a largely unknown environment presented the team five first stage F-1 engines experienced some minor with n"lany engineering challenges. And they had to problems, but two of the five J-2 engines on the second balance the imperative of maximizing the chance of a stage failed, as did the single J-2 on the third stage. The successful landing with ensuring the safety of the astro­ Saturn V successfully achieved orbit, but had this been nauts aboard. a manned mission, the failure of the J-2 engines would In the initial designs, those goals were in conflict; the have put a moon landing in jeopardy. weight of the Lunar Module as first drawn up was beyond The engineers at Rocketdyne, the engine manufac- specifications. Looking for any place where weight could

32 mechanical engineering I July 2009 Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021 Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021

be cut, Kelly focused on the windows, which were large tion, and the NASA leadership enthusiastically endorsed and heavy. Such large windows would provide the astro­ the change. From that point, the Lunar Module took on nauts with a good field of view as they sat in their seats the angular shape that is so familiar tod;q. during the landing phase. Kelly assembled a team of his engineers, which included Bill Rathke, Bob Carbee, John Rigsby, Gene H arms, and Howard Sherman to dis­ The engineers who designed the remarkable pieces of cuss options. As the discussion progressed an important space hardware were only a part ofthe overall Apollo question was asked, "What if we get rid of the seats?" team. Thousands of engineers were involved in launch Kelly called it "a brilliant, paradigm-shifting question." processing and monitoring the flights. In an era when Seats were not necessary given the engine thrusts needed computer systems were primitive compared to what we to navigate in the weak gravity of the moon. The astro­ have today, constant communication between the astro­ nauts' legs could support them well enough. Removing nauts and an army of engineers back in Houston was the seats and having the astronauts stand during the land­ critical to ensure the safety of the astronauts as well as the ing meant they could be closer to the windows, enabling success of the mission. a good view though a much smaller window. For instance, as the Lunar Module Eagle made its Also, reducing the window size and removing the powered descent to the lunar surface, a program alarm flight seats would not only greatly reduce the weight but sounded at an altitude of 33,000 feet. Commander Neil also increase the usable volume inside the cabin for the Armstrong called out, "It's a 1202." astronauts. Several design problems could be solved in Back at Mission Control in Houston, even with hun­ one stroke. dreds of simulated landings under their belts, no one was Rathke and Carbee spent that night developing draw­ quite sure what a "1202" alarm meant. Would the land­ ings of the new LM design. The engineering team met ing need to be aborted? The engineers in Houston had again and made the decision to propose this modifica- about 15 seconds to make a decision.

34 mechanical enginee ri ng I July 2009 The computers in the LM were incapable of printing out After conferring, Bales and Garman agreed that as long an error message in plain English; instead, they used a series as the overload was intermittent, there was no safety-of­ offour-digit codes. There were hundreds of such codes and flight issue. The landing could continue. in some cases one had to look up what the code meant. Just nine seconds after receiving Armstrong's message, The person on the ground who was in charge of monitor­ Bales asked the Capcom-the capsule communicator­ ing the Lunar Module's guidance computer was a 26-year­ to inform the astronauts, "We're go on that alarm." With old flight controller named Steve Bales. Bales, and his coun­ Armstrong and Aldrin at the controls, the Lunar Module terpart behind the scenes, Jack Garman, were both familiar continued to descend until 3:20 in the afternoon, Hous­ with the "1202" code. The LM's computer was being asked ton time, on July 20, 1969. to do too much and was being intermittently overloaded. The Eagle had landed. _ Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/131/07/28/6356995/me-2009-jul2.pdf by guest on 29 September 2021