In May 1961, President John F. Kennedy declared his goal to send a man to the Moon. The United States had accomplished precisely 15 minutes of human spaceflight time, Alan Shepard’s suborbital flight in the Mercury space capsule, designated Freedom 7. More than 400,000 Engineers were committed to Apollo. They are the unacknowledged heroes behind the Apollo Project.
And in the run-up to that achievement, the American space program had absorbed a series of high-profile embarrassments as the Soviet Union, with which the U.S. competed in a so-called Space Race, seemed to remain one step ahead.
The Goal to Land a Man on The Moon
To state so publicly, the goal to land a man on the Moon before the end of the decade was to risk another humbling loss. “We choose to go to the moon in this decade and do the other things,” Kennedy announced in a speech at the prestigious Rice University in September 1962, “not because they are easy, but because they are hard.” And it was very hard.
The president’s intention may have been prestige and politics during the Cold War. But America’s political fates were now in the hands of its best engineers. At the moment of President Kennedy’s announcement, the technology, the infrastructure, the hardware, and the technical workforce needed to accomplish this goal did not yet exist.
More Than 400,000 Engineers Committed to Apollo
At the time, the public spotlight shined on the face of the space program, the NASA astronauts who had already become national heroes. Most people didn’t realize the massive harnessing of America’s technological resources that occurred to make the moon landing possible. More than 400,000 engineers, scientists, and technicians working for more than 20,000 companies and universities contributed to Apollo’s success.
The engineers are not household names. Collectively, however, they overcame tremendous technological challenges with creativity, decisions, innovation, and persistence. Designs were sometimes risky, but always well thought out and, on occasion, elegantly simple.
It Took Thousands of Engineers to Make it Possible
While most of the commemorations will feature Neil Armstrong and Buzz Aldrin, who went to the Moon, it took the works of people like Houbolt, Carbee, Rigsby, Harms, Mueller, Castenholz, McClure, Kelly, Rathke, Sherman, Bales, Garman, and thousands of engineers just like them to make it possible. It is simply impossible not to be in awe of what they accomplished in only eight years.
Immediately following President Kennedy’s announcement, NASA managers asked themselves, “How do you get to the moon?” It wasn’t the first time that engineers had speculated on the problem: In the early 1950s, for instance, Collier’s magazine had published a famous series of articles by leading scientists and engineers detailing a plan to send men to the Moon and Mars. But suddenly, the question had turned from being a hypothetical exercise to a matter of national importance.
The Architecture of Launching a Man to The Moon
One of the most significant issues to settle was the mission architecture. The steps through which spacecraft would be launched landed on the lunar surface and returned safely back to Earth. For instance, one potential mission architecture involved launching a single person vehicle directly to the Moon and returning the entire spacecraft to Earth.
Although straightforward, such a mission would entail launching a prohibitively large mass with a single rocket, and that was beyond the scope of what was possible in the 1960s.
Credit: Wikipedia.
Earth Orbit Rendezvous, (EOR)
Instead, the mission idea initially embraced by NASA was called Earth Orbit Rendezvous. EOR included the launch of two rockets with all of the components needed for a lunar mission. In Earth orbit, the two rockets would rendezvous and dock, and then the combined spacecraft would continue to the Moon. This whole spacecraft would land on the lunar surface and return to Earth when the mission was completed.
The other concept was not given much faith by the NASA hierarchy, as 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.
Credit: Wikipedia.
NASA’s Opposition to LOR
On return, the lunar module would rendezvous and dock with the mother ship; the LM would then be discarded, and the astronauts would return to Earth in the mother ship. NASA’s opposition to LOR centered on the complexity and uncertainty of 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. The results of Houbolt were obvious. LOR made it possible to use lighter and smaller spacecraft, therefore making the scale of the entire project more straightforward. Nevertheless, Houbolt could not convince his bosses, and he did what most would consider career suicide by going around them directly to NASA’s leaders in Washington.
NASA Adopted The LOR Concept
Houbolt’s stubborn persistence in the face of considerable opposition and the validity of his engineering calculations 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 lunar flight.
The Apollo program’s linchpin was a launch vehicle powerful enough to propel the mother ship · and lunar landing craft to the Moon. Without that critical 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.
Saturn V an Engineering Masterpiece
Their solution, the engineering masterpiece is known as the Saturn V, was a technological leap over anything the United States had in its inventory at the time. Consisting of three stages holding more than 3 million parts in total, the Saturn V would tower some 363 feet when fully stacked. As designed, the behemoth weighed more than 6 million pounds, and its five F-1 engines would produce 7.5 million pounds of thrust.
One day it would be the most powerful rocket ever launched. But in 1962, it was just an idea on a drawing board. Over the next five years, Wernher von Braun and his team, along with prime contractors Boeing, North American, Douglas, and Rocketdyne, worked to design, manufacture, and test the Saturn V. It was a massive engineering project that pushed the boundaries of the technology and manufacturing methods.
George Mueller, an Engineering Manager
In 1963, George Mueller, an engineering manager from the industry who had helped develop the Minuteman ballistic missile for the Air Force, was brought in as the associate administrator for human-crewed space flight. Mueller conducted a top-to-bottom review of the Saturn V program and grew concerned over Wernher von Braun’s testing plan.
Wernher was meticulous and proposed testing the rocket’s first stage by launching it with dummy upper stages. If that flight succeeded, the tests would proceed incrementally from there with dummy stages being replaced by live ones. Discounting the additional cost of manufacturing multiple test stages, Mueller questioned the time it would take to conduct all of the launches von Braun proposed.
Launching a Fully Assembled Saturn V
NASA would never achieve the “end of 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 Saturn V with all of the stages stacked and fueled. Mueller’s approach was used in the Minuteman Project, and while it was much riskier, it would enable the team to meet Kennedy’s timetable.
Mueller, using strong engineering arguments, ultimately persuaded Wernher von Braun. The all-up testing concept was put to its first test in November 1967 when the Saturn V made its debut launch. Except for vibration problems, the rocket performed so well that some testing instrumentation was removed for the second flight in April 1968.
Apollo 6
That test, designated Apollo 6, did not go well. The five first stage F-1 engines experienced some minor problems, but two of the five J -2 engines on the second stage failed, as did the single J-2 on the third stage. The Saturn V successfully achieved orbit, but had this been a human-crewed mission, the J-2 engines’ failure would have put a moon landing in jeopardy. The engineers at Rocketdyne worked overtime to determine the cause of the problem.
The J-2 engine 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 telemetry 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, and again without failure.
The NASA Engineers Watched Films of Their Tests
Frustrated, and with the weight of the entire Apollo program bearing 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 space than on the ground?”
The NASA engineers watched films of their tests and saw that ice was building up on the lines carrying supercooled liquid hydrogen and liquid oxygen. The fluid lines were flexible and were sensitive to vibrations. Could the ice, which needed air to form, be protecting the lines during ground tests? Castenholz and McClure used a specialized test chamber to study the components under a vacuum, and the fluid lines failed.
The Saturn V Rocket Was Now Ready to Carry Astronauts
A simple engineering fix that involved adding steel mesh around the lines would prevent future failures. The Saturn V rocket was now ready to carry astronauts. NASA also had to develop a landing craft to take a pair of astronauts down to the Moon’s surface.
The lander, known as the Lunar Module (LM), would serve as a shelter and base of operations on the Moon’s surface, and then launch the astronauts back into lunar orbit to rendezvous with the mother ship, the Command/Service Module. The responsibility for designing the Lunar Module fell to Thomas Kelly and his team of engineers at Grumman Aviation (now known as Northrop Grumman).
The Weight of The Lunar Module
Designing a spacecraft for a mostly unknown environment presented the team with engineering challenges. And the Moon’s surface imperative of maximizing the chance of a successful landing with ensuring the astronauts’ safety aboard. In the initial designs, those goals were in conflict; the weight of the Lunar Module as first drawn up was beyond specifications.
Looking for any place where weight could be cut, Kelly focused on the windows, which were large and with a good view as they sat in their seats during the landing phase. Kelly assembled a team of his engineers, including Bill Rathke, Bob Carbee, John Rigsby, Gene H Arms, and Howard Sherman, to discuss the options.
“What if we just get rid of the seats?”
As the discussion progressed, an important question was asked. “What if we just get rid of the seats?” Kelly called it “a brilliant, paradigm-shifting question.” The seats were not necessary, given the engine thrusts needed to navigate in the weak gravity of the Moon. The astronauts’ legs could support them well enough.
Removing the seats and having the astronauts standing during the landing meant they could be closer to the windows, enabling a good view through a much smaller window. Also, reducing the window size and removing the flight seats would significantly reduce the weight and increase the usable volume inside the cabin for the crew.
“1202” Alarm
The engineers who designed the remarkable pieces of space hardware were only a part of the overall NASA Apollo team. Thousands of engineers were involved in monitoring and launch processing the flights. In a time when computer systems were primitive compared to what we have today, constant communication between the astronauts and a multitude of engineers back in Houston was critical to guarantee the safety of the astronauts as well as the success of the mission.
For instance, as the Lunar Module Eagle made its powered descent to the lunar surface, a program alarm sounded at an altitude of 33,000 feet. Commander Neil Armstrong called out, “It’s a 1202.” Back at Mission Control in Houston, even with hundreds of simulated landings under their belts, no one was quite sure what a “1202” alarm meant. Would the landing need to be aborted? The engineers in Houston had about 15 seconds to make a decision.
Flight Controller Steve Bales
The computers in the Lunar Module were incapable of printing out an error message in understandable English; instead, they used a series of four-digit codes. There were hundreds of such codes, and in some cases, one had to look up what the code meant. The man on the ground who was in charge of monitoring the Lunar Module’s guidance computer was a 26-year old flight controller called Steve Bales.
Bales, and his counterpart behind the scenes, Jack Garman, were both familiar with the “1202” code. The LM’s computer was being asked to do too much and was being intermittently overloaded. After conferring, Bales and Garman agreed that as long as the overload was intermittent, there was no safety issue.
The landing could continue. Just nine seconds after receiving Armstrong’s message, Bales asked the Capcom-the capsule communicator to inform the astronauts, “We’re go on that alarm.” With Neil Armstrong and Buzz Aldrin at the controls, the Lunar Module continued to descend until 3:20 in the afternoon, Houston time, on July 20, 1969. The Eagle had landed.
Thanks for reading. I hope you enjoyed this article. If you want to know more about the Apollo Project and its unsung heroes, then head over to this article about Pad Leader Guenter Wendt.