Can Barack Obama write computer code

Software pioneer Margaret Hamilton : Their code got the Apollo astronauts safely to the moon

You can find our countdown to the moon landing in 1969 here.

It was a minor mishap that could have led to the failure of the Apollo 11 mission: three minutes before the moon landing, the deactivated rendezvous radar began to send massive amounts of data to the control system due to a faulty design undetected by the crew.

Although the on-board computer was almost at full capacity during the approach, it suddenly provided another 15 percent additional power. Margaret Hamilton was the main reason why the computer did not crash.

It wasn't just the hardware that made the eagle land safely

The Apollo Guidance Computer's chief programmer had foreseen that even the best astronauts could make mistakes. For this reason, a control system was developed under her direction that could independently set priorities. The data for the landing approach were weighted higher than the data from the radar.

Also because of this, Commander Neil Armstrong was able to report to Houston a short time later: "The Eagle has landed!", The eagle has landed. In the early morning of July 21, 1969, he became the first person to walk on the moon.

To this day, the perception of the Apollo 11 mission has been shaped by hardware: for example, the hissing engines of the Saturn rocket, the reflective helmets of the spacesuits or the spider-shaped legs of the Eagle lander.

In fact, the flight to the moon is associated with a digital paradigm shift that is still having an impact today. As early as the planning phase, the engineers recognized that, in addition to the hardware, the software would also play a decisive role in the success of the mission.

One of the first software developers in the world

Margaret Hamilton was at the center of this development as a programmer. While preparing for the moon flight, she invented the term "software engineering", which she first used as a joke and later as a serious description of her efforts to continuously improve technology. This is one of the reasons why she is considered one of the first "software developers" in the world.

Until then, writing code had been seen as a minor task in the development of computer technology. There was simply no awareness of the importance of controlling sophisticated hardware.

This was also reflected in the initial budgeting of the Apollo mission. While billions were budgeted for the development of the hardware, the programming of the software was not taken into account. Only later did the engineers discover that the lander would also need a functioning on-board computer.

Hamilton, then 29 years old, after completing her bachelor's degree in mathematics at Earlham College, worked for artificial intelligence (AI) pioneer Marvin Minsky and developed weather forecasting software with chaos theorist Edward Norton Lorenz.

The digital autopilot was a world first at the time

She later programmed parts of the control system for the Semi-Automatic Ground Environment (SAGE), the US Department of Defense's first computerized air defense system. In 1965, Hamilton was finally hired by the Massachusetts Institute of Technology (MIT) as a project manager on the Apollo project. Your task was to implement the control of the on-board computer.

The computer was to contain the world's first digital autopilot flight controller. Hamilton had to do some real pioneering work in programming. NASA also recognized how important software would become for the flight to the moon: Hamilton's team grew to include up to 100 employees.

A key problem was the susceptibility of magnetic storage devices to radiation and heat. The solution for this was a construction that was insane from today's point of view: the on-board computer was equipped with a so-called "thread memory".

In months of labor, copper wires were drawn through a matrix of iron rings by seamstresses. If the wire ran through such a ring, a "1" was read out; if the wire ran around a ring, this signaled the value "0" to the system.

Thread memories were designed in such a way that they could only be read out. It was not possible to save new information, but in the event of a power failure it would remain secure against any form of data loss. The trace of the wires through the landscape of Eisenringen recreated all the zeros and ones that Hamilton and her team programmed. If you will, the code was built in.

Astronauts also make mistakes

Although the system was very solidly constructed, another problem remained: the blindness of the controls to the real meaning of a given program in a particular phase of the flight.

Just by accident, Hamilton realized how important this could be for the Apollo mission. Her daughter Lauren, who she often took to work with her, was playing a few buttons on the simulator one day while Hamilton was rehearsing a mission. The girl came up with a button that was actually intended for take-off preparations while the device was already simulating the flight to the moon. The system crashed. Had this happened under real conditions, it would have meant the loss of the lunar module.

Hamilton realized that without backup systems and protective devices, one wrong keystroke could be enough to cause the entire mission to fail. "I proposed a change to prevent a pre-launch program from being selected in-flight. But those in charge at MIT and NASA said the astronauts were too trained to make such a mistake," recalled Hamilton last week in an interview with the Guardian.

However, when exactly such a human error occurred on the Apollo 8 flight, the priorities changed. Hamilton developed the control system that later, despite the incorrectly designed radar, secured the landing on the moon.

A thousand pages of code and a great honor

"Our software had to be extremely reliable and able to detect a bug and fix it at any time during the mission," she told the Guardian. In previous public appearances, she also spoke of the pressure she felt herself in the preparation phase for Apollo 11: her fear that she might be the one everyone would point to in the end if the lunar mission had failed due to a programming error.

In fact, there was not a single software bug during the entire mission. Their system was more reliable than any other that has ever been shot into space by humans.

Hamilton stayed at MIT until 1976, after which he started his own software company. The now 82-year-old has never been forgotten. This is probably also due to the iconic photo that shows Hamilton next to the stacked, many thousands of pages long code for the lander.

In 2003 Hamilton was honored with the "NASA Exceptional Space Act Award", the associated prize sum of 37,200 dollars was the highest ever paid out for this award. In 2016, the then US President Barack Obama presented the software provider with the "Presidential Medal of Freedom" - the highest civilian award in the USA.

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