Neil Armstrong's words crackled through the speakers at NASA's Mission Control in Houston, signaling that men first touched down on the moon.
The Eagle lunar landing module was one of the world's most important engineering achievements. The key challenge: to keep it as light as possible.
Grumman Aircraft Engineering Corp., later Grumman Aerospace Corp., designed and built the lunar lander at its facility in Bethpage, N.Y., under a $1.6 billion contract with NASA. It was first of six lunar landers built for the Apollo program. Grumman beat out nine other companies for the contract.
According to the American Society of Mechanical Engineers, before the program ended, more than 3,000 engineers and 7,000 other Grumman employees hand built 13 full versions of the craft.
Little was known about the lunar surface when construction began in 1962, so the engineers designed cantilever landing gear consisting of four leg assemblies, each ending in a dish-shaped landing pad, so the craft could land safely and remain upright on a variety of surfaces.
What would later be named the Eagle measured, with its legs extended, 23 feet high and 14 feet across.
Don Rosato, a plastics industry veteran, was then a young materials engineer at Grumman, working on composite lunar modular struts for the lunar lander, among other Apollo-related projects.
Rosato said that originally, four composite lunar module struts were fabricated by Grumman and the Hercules Powder Co., later part of Ashland Inc., from boron (from AVCO Specialty Materials), graphite (Union Carbide and Courtaulds), and epoxy (Ciba Geigy, now Huntsman) to save weight while retaining high strength.
But he said NASA ultimately returned to more traditional, heavier aluminum struts on Apollo 11. Remembering the tragic Apollo 1 cabin fire that killed all three astronauts on a launch rehearsal test on Jan. 27, 1967, composites were deemed potential flammability threats from outgassing, Rosato said.
Rosato said boron/graphite epoxy composites were used as leg inserts on three of the later moon flights, Apollo 14, 15 and 16. The cylindrical inserts were fabricated by pressurizing a nylon bag inside a metal tubular female mold using filament-wound cross plies and longitudinal tape layers, he said.
Rosato said Grumman was his first plastics industry job. He worked under George Lubin, who was Grumman's chief materials scientist. Lubin, a pioneer in advanced structural composites, was inducted into the Plastics Hall of Fame in 1982.
At Grumman, Lubin was in charge of all materials, not just composites.
Rosato was a boy when the Russians sent up Sputnik in 1957, starting the space race. That was something he had in common with other young engineers who worked on the Apollo project.
"It was a generation of Sputnik-inspired engineers. In high school, we were taking advanced math and science classes," he recalled.
Apollo 11 was demanding and exciting, he said.
"It was a big team effort. You worked long hours. You thought, this is teamwork and this is something that's bigger than ourselves," Rosato said. "The biggest thing is you had very experienced engineers, probably in their 40s, 50s and 60s."
They demanded hard work and excellence, he said.
Grumman provided details about the lunar module to NASA for a detailed press kit in 1969.
The piston-loaded primary strut absorbed the compression load of the landing and supported the Eagle on the lunar surface. Engineers developed crushable aluminum honeycomb cartridges to act as shock absorbers — eliminating the need for thick-walled, heavy, pneumatic-type struts.
Because the lunar lander would be exposed to solar radiation and tiny micrometeoroids, the ascent stage was enclosed within a thermal blanket and a protective shield. Glass-fiber standoffs, with low thermal conductivity, held the blanket away from the structural skin.
Parts of the lunar module were wrapped in film that had the appearance of gold foil — a multilayer blanket of DuPont Kapton polyimide film and Mylar PET film, which acted as an insulator to protect the Eagle from solar radiation and unrelenting heat-cold cycles.
The film reduced the impact of the extreme temperature variations, from about 250° F in the sunlight to -250° F in the shade.
The insulation was intentionally crumpled by hand to minimize contact points that could leak between the layers. Like all components, weight reduction was a big feature — the film blanket was much lighter than more solid types of heat shields.
The U.S. flag the astronauts placed on the moon was made of DuPont nylon.