Tindall’s work was critical for the Apollo mission
Published 5:56 am Saturday, July 31, 2021
EDITOR’S NOTE: Don Lee is taking a break from his column this week. The following is a piece that originally was published on July 24, 2019.
One of those impossible tasks needed to make the Apollo project succeed was the miniaturization of the computer, which would, in real time, provide control of the Apollo components, especially the moon lander.
Some of us remember the time before the Apollo era when we communicated with the computers via punched cards.
The computers sometimes occupied a large room with spinning big disks or reels of magnetic tape.
A division of the MIT university, labeled the Instrumentation Lab, was tasked with job to control the moon lander with a computer.
It had to handle the job in real time, no punched cards and it had to react in microseconds.
To top that, they had to design and build a computer that could fit into one cubic foot of volume. Time was important since it had to be completed in time to be tested and ready to go well before the end of the 60s decade as promised by President John F. Kennedy in 1961.
Although the Instrumentation Lab of MIT was credited with accomplishing the task, it was through the efforts of Bill Tindall.
It was he who pushed and directed the team to do the job, according to Charles Fishman in his book, “One Giant Leap.”
He found a mess when he arrived at the lab, but, eventually, they had designed a computer program that required 42 percent more computer code than there was available in memory.
They finally designed the Apollo Guidance Computer (AGC) that could execute 85,000 instructions per second. By comparison, a present day smart phone can execute 5 trillion instructions per second.
Tindall was an accomplished mathematician who was an expert in calculating orbital mechanics.
He was famous for his Tindallgrams. He wrote over a thousand of them over those six years of directing the MIT Instrumentation Lab.
He usually was very direct and was good at pointing out what they did not need in the AGC.
They built into the software the ability to abandon those instructions that were not essential at the moment and have it concentrate on the essential ones — like landing the moon lander.
The person responsible for the direction of the Instrumentation Lab within MIT was Stark Draper, who incidently, was relation to the Stark Nurseries of Missouri who founded and propagated the West Virginia Golden Delicious apple.
He was a pioneer in the development of the inertial guidance system for airplanes before we depended on GPS to direct us.
The inertial guidance system was used by one of notable people from Lawrence County Airport, Howard Mayes, who used the system to fly a team of scientists around the world to observe a total eclipse of the sun.
Although I strayed away from the Apollo program, I thought this was interesting.
To emphasize the massive effort to put a man on the moon before the Russians, we spent almost a million man hours on earth for every hour the Apollo spent in space.
I would like to give credit to Charles Fisher for the details and information that I gleaned from his book, “One Giant Leap.” I recommend that you read it for more information about the Apollo program.
Don Lee, a pilot flying out of Lawrence County Airport since 1970, has been in charge of equipment and grounds maintenance for the last several years. He can be reached at firstname.lastname@example.org.