Weaving Apollo computers
Sitting next to each other, one line behind another, hundreds of women were hitting and setting fire to the Massachusetts factory in the mid-1960s. Some came from watchmaking and most textiles. They were hired by the company Raytheon, which was now staff of its electronics department. But they kept doing what they knew how to do best: knitting. Instead of cotton, silk or nylon threads, copper threads were now in the hands, with great skill, to one side and the other; the first people were weaving computer memories that allowed them to reach the Moon.
These computers were one of the most important keys to the success of the Apollo program. Moon missions operations were so complex that it was impossible to delegate them to the crew. Because of the fear that the Russians could block communications, NASA was clear from the beginning that the only way to carry out these missions was to install computers to spacecraft. These computers would guide missions.
In fact, the first contract signed in the Apollo program was for the construction of computers. The contract was signed by NASA with the Massachusetts Institute of Technology (MIT).
For MIT engineers it was not a challenge at all. At that time, computers occupied full rooms, consumed a lot of energy and needed constant repairs. It was unthinkable to get into a spaceship.
If they wanted to get to the moon, they had to make a computer much lighter and smaller and consume less than a normal bulb. Moreover, it had to be as powerful as to perform all the necessary calculations. But not only that, these computers had to be adapted to the extreme situations of a space trip: sudden vibrations, important temperature changes... And above all, they could not miss at all. The lives of astronauts could not be lost due to a hardware or software failure.
However, MIT engineers met the challenge and designed the computer for the Apollo pogram. Computers had all the faith. "From our point of view, the computer could conduct a mission without requiring astronauts," recalled engineer Eldon Hall, who worked on the design of those computers. But many others did not believe it worked. "The biggest problem was convincing people that computers could be reliable," Hall said. "This was more difficult than designing the computer."
Each computer had a memory of 160 kilobytes and a size of 61x32x17 cm. In each mission two would be taken, the service module would have one and the moon module another.
The problem of size and consumption was greatly helped by a cutting-edge technology of the time, the integrated circuits (better known today as chips). About 4,000 would be used per computer. The use of integrated circuits was a bold decision, in which only a couple of years this technology was generated and they still did not know very well the reliability they had. "It was an extremely bold decision, but probably essential for the success of the mission," Hall said.
However, not the entire computer was made with integrated circuits. To make the memory of the computer as robust and safe as possible, the "rope memory" would be used, that is, the memory of copper wire woven into very small magnetic rings. All the software that would guide the mission was written with those copper threads in binary code: by passing the thread through the center of the magnetic ring a 0 was obtained and by passing through the outside of the ring, a 1.
Raytheon was responsible for the manufacture of computers and due to the large expansion of the textile industry in the Massachusetts region, where the company was located, mainly hired weavers to weave computer memories. It was a great work. It started with about 800 workers and after a year it became 2,000 to finish the work on time.
NASA knew perfectly well that the success of the greatest space adventure in history depended heavily on the women of Raytheon. Control and pressure was enormous. The cleaning had to be taken care of with great rigor, and each of the components had to be reviewed by three or four people. In addition, "we had a team of inspectors from the federal government to constantly monitor our work," worker Mary Lou Rogers told the BBC.
On the other hand, high officials and NASA astronauts were often sent to visit the factory. These visits were organized to motivate workers to feel part of the program, and to see that in their hands there were lives of real people. "We went to the cafeteria and there the astronauts appeared," Rogers said. "They told us how the mission to the Moon was going to be and thanked us for the great work we were doing."
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