Neil Armstrong could never escape the spotlight that always followed the world’s most famous astronaut.

But behind the scenes, more than 400,000 government employees and private contractors toiled in anonymity on the Apollo 11 mission, helping to ensure NASA would win the space race with the Soviet Union. For years, engineers, scientists and even security guards worked feverishly around the clock to answer President John F. Kennedy’s call to put the first man on the moon and return him safely to earth.

For Gerard “Jerry” Elverum, work on the “moon shot” started in 1960, a year before the Apollo program formally began, with him designing the rocket engine that powered the descent of the lunar module (LM) used on all six moon landings. Meanwhile, Howard “Howie” Frauenberger alternated college studies with a Grumman Corporation internship that had him participating in three high-profile scientific tests on Apollo.

Their ingenuity, scientific insight and diligence enabled Armstrong and Buzz Aldrin to bounce around the moon’s surface on July 20, 1969. Millions of people back on Earth watched in astonishment, while Elverum and Frauenberger observed history with a mix of confidence and the slightest of worries. Now, as the 50th anniversary of the first lunar landing approaches, the retired engineers look back on their accomplishments with wonder and pride.

“No matter what you were working on, there was this intense feeling that you have to get it right,” Frauenberger recalled. Elverum remembers being driven by an expectation that individual efforts had to match the collective national drive to achieve the extraordinary. “We had a goal and knew we had to be committed to make it work,” he said.

Confidence in a Design

In 1960, a year after Elverum joined Grumman legacy company Space Technology Laboratories (STL), he started creating one of the most critical mechanical components for a moon landing. The LM needed an engine powerful enough to separate from Apollo’s command and service module (CSM) in lunar orbit but also nimble enough for a soft and precise touchdown on the moon’s surface. Elverum knew he had the right stuff, but it took a bit of convincing.

Grumman Corporation was charged with developing and building the LM, and Rocketdyne — then one of the biggest rocket engine companies — had secured the job to create the spacecraft’s descent engine. But, as Elverum recalls, NASA was worried about Rocketdyne’s design. Hearing this, he showed his design to NASA officials, who wondered aloud about the legitimacy of an engineer from a largely unknown company. But tests supported Elverum’s belief that his rocket would consistently perform under all conditions. In 1963, NASA asked STL to build its engine as a backup to Rocketdyne’s product; a year later, it realized Elverum was correct all along.

Now 92 and living about 80 miles east of Los Angeles in Murrieta, California, Elverum still holds the patent on the concept of the lunar descent throttling engine. “The lunar module descent engine probably was the biggest challenge and the most outstanding technical development of Apollo,” according to “Chariots for Apollo,” a NASA history of the program.

“It had a dynamically stable configuration, so if there was a major disruption, it would recover within 10 seconds and could take all types of glitches,” Elverum said in a telephone interview. “I was convinced of that. And all through the time we were developing it, that had to be the most critical thing that NASA and Grumman would have to see. I had a lot of confidence in it.”

The throttling capabilities of the engine enabled Armstrong to safely guide the LM to a new landing spot when it overshot the planned touchdown area. “During those 12 minutes, it felt like I had the whole world on my shoulder,” Elverum said.

His engine performed capably not just on the Apollo 11 mission but on five others. On the Apollo 13 mission, when the engine intended to bring astronauts home was irreparably damaged in an explosion on the way to the moon, Elverum’s engine ultimately brought them back to earth. For that and other career accomplishments, he was elected to the National Academy of Engineering in 1987. He retired three years later.

A Dream Internship

Frauenberger attended Pratt Institute, a university in his native Brooklyn, New York, because it offered a unique work-study program. Although it would take five years to earn an engineering degree, he gained work experience by interning for three full semesters at Grumman’s campus in Bethpage, New York.

It didn’t take long during his first internship semester, in spring 1966, to be assigned to the LM project, as he helped vouchsafe the dependability of the craft’s landing gear. “It better work, because if it doesn’t work, you can’t land,” Frauenberger joked in a recent telephone interview from his home in Malverne, New York.

Not long after, Frauenberger found himself in the cold-flow test facility, using inert gases in a methodical assessment of the functionality of ascent and descent vehicles that were ready to be shipped to Kennedy Space Center in Cape Canaveral, Florida. “It was a test that had to keep going and going around the clock for about six or seven days for each module,” he recalled.

Two years later, with NASA pushing hard to land the first man on the moon, Frauenberger had one more Apollo assignment: help the thermodynamic engineering department conduct an analysis of the LM’s cabin, simulating the conditions it would face on the moon. He ran a computer program that examined “how the temperature would vary from the landing to the take-off from the moon,” he said. “It was for the sake of the astronauts and the electronic equipment.”

Several times throughout his internship, Apollo astronauts stopped by the Grumman facility to check on progress and inspire employees. Frauenberger has forgotten which astronauts visited because at the time he was unabashedly giddy about meeting his heroes. “You don’t wash your hands for days. It was the closest thing to meeting God.”

Frauenberger graduated in the summer of 1969, just in time to witness the moon landing on television while at a friend’s birthday party. Five decades later, he believes his work on Apollo was the pinnacle of his career. His colleagues might disagree. Grumman hired him after college, and he spent 47 years with the company, working on, among several projects, the development of the F-14 Tomcat fighter jet and the MQ-4C Triton. Now retired, the 72-year-old holds the distinguished title of Grumman technical fellow.

Frauenberger can’t believe 50 years have passed since Armstrong stepped down from the ladder of Apollo 11 and left his first imprint on lunar soil. Those heady times still seem like they happened yesterday. “The whole world kind of stopped,” he said. “It is one of the greatest events in history. It is certainly one of the greatest aerospace events.”