Big Optimism: The Lauren Bug
Or, how the moon landing 57 years ago this week almost had to be scrapped at the very last minute.
It’s the anniversary of the failed attempt to land on the moon, July 20, 1969, and we all know the story:
On July 16, 1969, a Saturn V rocket carrying Neil Armstrong, Buzz Aldrin, and Michael Collins left Earth for the moon.
Three days later, Armstrong and Aldrin climbed into the lunar module and began their descent toward the surface, leaving Collins orbiting alone in the command ship.
At around 30,000 feet, the guidance computer running that descent became overwhelmed with more tasks than it could process in time, and Mission Control aborted eight-year, $25 billion mission.
O.K., back to reality — the moon landing was a big success, 57 years ago this week. But if not for a series of small decisions and more than a bit of luck, the three-point story above might actually have been how things turned out.
This is that story. Its protagonist is a woman named Margaret Hamilton.
Born in Indiana in 1936, she studied math (with a minor in philosophy), then got married and had a daughter, and then moved to Boston so her husband could attend Harvard Law school. Hamilton planned on graduate school herself, but she detoured, getting a job to support her family writing software in the meteorology department at Massachusetts Institute of Technology.
Later, MIT’s Instrumentation Laboratory won the contract to write the flight software for NASA’s new Apollo program, and Hamilton moved over to that project. Within a few years, she was directing the team that wrote the code for the descent of the lunar module.
I’ll let her explain a key insight she had, in her own words:
Often in the evening or at weekends I would bring my young daughter, Lauren, into work with me.
One day, she was with me when I was doing a simulation of a mission to the moon. She liked to imitate me – playing astronaut. She started hitting keys and all of a sudden, the simulation started. Then she pressed other keys and the simulation crashed. She had selected a program which was supposed to be run prior to launch – when she was already “on the way” to the moon.
The computer had so little space, it had wiped the navigation data taking her to the moon. I thought: my God – this could inadvertently happen in a real mission.
I suggested a program change to prevent a prelaunch program being selected during flight. But the higher-ups at MIT and Nasa said the astronauts were too well trained to make such a mistake.
Midcourse on the very next mission – Apollo 8 – one of the astronauts on board accidentally did exactly what Lauren had done. The Lauren bug! It created much havoc and required the mission to be reconfigured.
After that, they let me put the program change in, all right.
All of which brings us to July 20, 1969 — and what actually happened with the moon landing.
Armstrong, Aldrin and Collins made it to the moon; Armstrong and Aldrin began their descent toward the surface.
But at 30,000 feet, the computer running software that Hamilton’s team had designed gave a warning code. Here’s the radio transcript:
Armstrong: “Program alarm. It’s a 1202.”
Aldrin: “1202.”
Armstrong: “Give us a reading on the 1202 program alarm.”
Much as Hamilton had predicted — and at the most inopportune moment — the computer had in fact been overwhelmed; later NASA would figure out that a rendezvous radar switch had been left in the wrong position, flooding the computer with data it didn’t need for landing.
One of the engineers back in the control room, 24-year-old Jack Garman, had handwritten a list of every alarm the Apollo Guidance Computer could throw; he told his bosses they were O.K., and word was relayed up the chain.
Duke (CAPCOM): “Roger. We got you... we’re go on that alarm.”
Ready for the irony in this story?
The MIT job Hamilton took in order to put her husband through law school was in the research group of a meteorologist named Edward Lorenz, writing weather-prediction code. This was at the exact moment Lorenz was working out what would become chaos theory — often known now as the butterfly effect.
It’s the idea a small, easily-dismissed variable in a complex system can determine everything downstream of it.
Like:
If Hamilton’s husband hadn’t gone to Harvard …
And she hadn’t taken the job at MIT and wound up ultimately working on Apollo …
And if she hadn’t brought her young daughter into the office, and her daughter hadn’t played with the computers …
And if the error little Lauren created hadn’t led to Hamilton’s insight and insistence…
The Apollo lunar landing software might actually have shut down when it was flooded with data on July 20, 1969.
And the fiction at the start of this newsletter might have been fact.
7 other moments to know from history this week
Sunday, July 19: “We hold these truths to be self-evident; that all men and women are created equal.” — From the Declaration of Sentiments, adopted at the first women’s rights convention organized by women, held in Seneca Falls, New York, on this day in 1848. Drafted primarily by Elizabeth Cady Stanton and modeled on the Declaration of Independence, it’s now regarded as the launching point of the organized women’s suffrage movement in America.
Monday, July 20: “We were sitting there and watching the first picture develop of the surface of another planet — from that surface of the other planet.” — Joel Levine, NASA research scientist, on Viking 1’s first transmitted image from Mars on this day in 1976. It was the first U.S. spacecraft to land successfully on another planet, after mission managers scrapped a symbolic July 4th touchdown date in favor of a safer landing site.
Tuesday, July 21: “It is the greatest Egyptian project since the time of the pharaohs.” — Abbas Sharaky, Cairo University water resources professor, on the Aswan High Dam, completed on this day in 1970. A decade in the building, it tamed the Nile’s flood-and-drought cycle for the first time in history and created Lake Nasser, one of the largest artificial lakes on Earth.
Wednesday, July 22: “I’ve got to get going; I’m in a hurry.” — Wiley Post, readying for the final leg of the solo around-the-world flight he completed on this day in 1933. Flying alone by autopilot and radio direction finder, he circled the globe in 7 days, 18 hours, and 49 minutes, beating his own two-man record from two years earlier by nearly a full day.
Thursday, July 23: “Of course, as you know now, that didn’t stop all those other people in St. Louis from claiming it was their invention.” — Author Elaine Greenstein, on the tangle of rival claims to the ice cream cone, said to have debuted at the St. Louis World’s Fair on this day in 1904. Confectioner Charles E. Menches is the most commonly credited inventor, one of at least half a dozen vendors who staked a claim.
Friday, July 24: “Suddenly I found myself confronted with the walls of ruined houses built of the finest quality of Inca stone work.” — Hiram Bingham, on first encountering Machu Picchu on this day in 1911. The Yale historian had been searching for a different lost Inca city entirely, guided there by local farmers who already knew the site well.
Saturday, July 25: “The American folk song has grown up.” — Joni Mitchell, on Bob Dylan’s electric set at the Newport Folk Festival on this day in 1965. The short, loud performance split the crowd between boos and cheers, and is now remembered as the moment folk gave way to rock.
Main story is fascinating. Funny how prospective puts things and events in a whole new light. So glad mom paid attention.
Too bad women weren’t in the room when the Declaration was hammered out.
I remember when Egypt announced their intention of building the Aswan Dam and the huge archeological project of moving Abu Simbel out of the flood zone. Even as a kid I was in love with ancient Egypt, the Pharaohs and of course, their tombs.
In 2008 I had the oppprtunity to travel with our Friendship Force group to Peru where Machu Pichu was the highlight of the trip. From experience I can say it is truly a magnificent site.
It is truly difficult for me to remain optimistic in this day and time.