Weaving the code for Apollo 11

Creative fabrication led to today's advanced manufacturing

Seamstresses from Massachusetts mills "weave" copper wire into code for the Apollo 11 computers.

This vintage photo shows part of the Apollo Guidance Computer assembly line at Raytheon. The company famously hired experienced seamstresses from Massachusetts mills to weave copper wire into code for the 1960s program.

The seamstresses threaded their needles through one magnetic core, then looped the copper wire around the next core before routing it into another. And another. 

They repeated this task thousands of times. They weren't weaving fabric; rather, they were building software. Each loop had one of two meanings; strung together, the twists formed binary language: 10110101.

Raytheon recruited women from the nearby Massachusetts mills for their exquisite manual dexterity, perfect for weaving the copper code that ran the guidance computers for the Apollo space missions of the 1960s and 1970s. It was one of the creative ways Raytheon helped to safely deliver mankind’s biggest leap. 

“It was actually like a needle-and-thread kind of an operation,” said Robert Zagrodnick, a former program manager for the Apollo Guidance Computer, which was built by Raytheon. “And they had manufacturing aids to help decide exactly where to thread it and that kind of thing, because they were threading the ones and zeroes for the program.”

The original moonshot

Raytheon's previous experience on the U.S. Navy's Polaris ballistic missile program informed its approach to building the Apollo spacecraft computers. Like its descendant, the Apollo Guidance Computer, the Polaris guidance system had to be small, accurate and absolutely reliable. Designers had made the critical decision to build a digital, rather than analog, computer for Polaris, a decision that carried forward to the Apollo 11 moon landing.

It was during the development of Polaris that "a positive working relationship was established between laboratory designers and Raytheon personnel," wrote MIT's Eldon Hall, who led the Apollo Guidance Computer design team, in a history of the project.

The Apollo computers began with blueprints designed at the MIT Instrumentation Lab. Hall and his fellow engineers had been introduced to computers only a few years before, in the age of MIT's Whirlwind, a large, high-speed-for-the-day machine that filled most of a building. Just a decade later, the Apollo computers needed to be the size of a suitcase and able to withstand the rigors of a trip to space. Most importantly, they had to work.

“Our role was...basically manufacturing and development, because we were clearly involved in new technology in many respects,” Zagrodnick said. “There was a big learning process throughout the whole program.”

Building straight from the design presented some challenges. The intended aluminum frame was too heavy; it was replaced with magnesium. The computer’s two sections caused cross-coupling issues when bolted together, forcing wiring redesign. And when vibrated, a thin metal section protecting the memory modules would chaff and create metallic dust and particles, causing more redesign.

The computer was also one of the first to use integrated circuits instead of transistors, a critical decision that laid the foundation for the smart technology of modern times.

Meanwhile, the company was hiring those women from Massachusetts mills and the closed Waltham Watch Company factory. The watchmaker had been located in Waltham, Massachusetts, since the 19th century. At the point when the Apollo program kicked into gear, Raytheon's Space and Information Systems Division was also in Waltham. (Today, you can find Raytheon Global Headquarters  there.)

The skills of the mill workers and the Waltham Watch employees were key to making the computer's precision parts. Raytheon even used early versions of today's clean rooms. Women workers were not allowed to wear makeup and employees with fresh suntans were kept off the line, lest flakes of peeling skin or Max Factor contaminate the components.

The creative approach

The creative approach also produced the transmitter that beamed Neil Armstrong's inspirational words back from the moon, which was powered by Raytheon Amplitron crossed-field microwave tubes.

Raytheon has been built on tube technology. In the 1920s, its gas rectifier tubes turned the home radio from a clumsy, battery-powered novelty to a practical, popular household appliance that could be plugged into a light socket or wall.

In early World War II, the British government turned to Raytheon for help making microwave tubes known as magnetrons for its radars. Britain couldn’t manufacture the tubes fast enough.

The problem was that the tube was built around a core that was machined out of solid copper. Raytheon engineer Percy Spencer — later known as the inventor of the microwave oven — innovated a process to build the core by stamping thin slices of metal, then fusing them together. Suddenly, thousands and thousands of the tubes could be produced more cheaply and very quickly.

Raytheon ended up supplying more than 80 percent of the magnetron tubes used in U.S. and British radars. 

The innovation never stops

Today, Raytheon uses emerging technologies such as virtual reality and 3-D printing to change how it designs and builds its products.

The company has six futuristic Immersive Design Centers, including 3-D, computer-assisted, virtual environments known as CAVE.

These futuristic installations allow engineers to collaborate remotely, sharing a virtual experience and literally walking through virtual systems, able to offer technical help over vast distances. Or guests can slip on a headset to take a factory tour without disrupting sensitive production lines, and new employees can train by virtually watching products being built from any angle, while receiving audio guidance and tips from the company’s most experienced assemblers. In addition, factory workers are brought in during 3D design reviews to catch potential issues early on.

“We get the operators in the CAVE, turn the lights down and put headsets on them, and they just open up and go crazy,” said Kendall Loomis, manager of the IDC in Tucson, Arizona. “The engineers can get the perspective of what it takes to build these parts (from) the people who build them, and fix manufacturing issues before the design is complete.”

And in the future, a Raytheon engineer will be able to send plans to 3-D-print a broken part to sailors at sea or soldiers in the field, then put on a VR headset and walk them through repairs. Because when you’ve already sent men to the moon with hand-sewn software, no idea seems impossible.

Published On: 03/11/2019
Last Updated: 06/20/2019