50 Years Ago–Getting Apollo 11 to the Moon on Less than the Power of a USB Stick

More than half a billion people watched the televised first moonwalk that took place on July 20, 1969.  It was a day so historic that space enthusiasts still celebrate it annually.  It was the day that marked the culmination of human endeavor, spirit, and perseverance.  And it can always be summed up in that now-famous sentence uttered by Neil Armstrong, “That is one small step for a man, one giant leap for mankind.”

Astronauts Neil Armstrong, Edwin “Buzz” Aldrin, and Michael Collins left Earth on July 16th from Cape Kennedy in Florida.  It was days later that Armstrong and Aldrin stepped foot onto the moon.  One of the most amazing things about this journey was that, by today’s standards, the NASA computing system was as basic as a pocket calculator.  Yet, the ingenious computer systems were able to help guide the astronauts over 221,000 miles of space and return them home safely.

The Astronauts used the Apollo Guidance Computer (AGC), a real-time operating system that enabled astronauts to enter simple commands by typing in pairs of nouns and verbs to control the spacecraft. It was more basic than the electronics in modern toasters that have computer controlled stop/start/defrost buttons. Experts cite the AGC as a fundamental part in the evolution in the integrated circuit.  It is regarded as the first embedded computer, allowing multiple commands to be entered and later executed by list of priority.

While the astronauts would probably have preferred to fly the spacecraft manually, only the AGC could provide the accuracy in navigation and control required to send them to the Moon and return them safely home again, independent of any Earth-based navigation system.

The importance of this computer was highlighted in a lecture by astronaut David Scott who said: “If you have a basket ball and a baseball 14 feet apart, where the baseball represents the moon and the basketball represents the Earth, and you take a piece of paper sideways, the thinness of the paper would be the corridor you have to hit when you come back.”

NASA’s Apollo program included multiple launches in the late 1960s and early 1970s and was designed mainly to land humans on the moon and bring them back to Earth safely.  Signs of the missions are still visible on the moon’s surface. Photos taken by the lunar orbiter show tracks made by lunar rovers and equipment left behind, including backpacks jettisoned by astronauts.

Knowing that a USB memory stick today is more powerful than the computers that put men on the moon is a testimony to the relentless pace of technological advances issued by human ingenuity.

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