September/October 2008

Digital Apollo

tells the story of man and machine in space

By Lissa Harris SM '08

Digital Apollo: Human and Machine in Spaceflight By David A. Mindell MIT Press, 2008, $29.95

On July 20, 1969, Neil Armstrong, gloved hand on the control stick, guided the Apollo 11 lunar module to rest on the surface of the moon. "Houston, Tranquility Base here," his voice crackled back to Earth. "The Eagle has landed."

Armstrong spoke those famous words with a silent partner at his side: the rugged and reliable Apollo guidance computer, which steered the spacecraft on the Apollo missions even though it had less memory and processing power than a modern-day cell phone. Conventional accounts of the Apollo 11 mission say that at the critical moment, the computer failed, and human ingenuity saved the day. In his new book, Digital Apollo, MIT historian David Mindell shows that the full story is a lot more complicated.

"Much has been written about Apollo, but little of it from a serious history-of-­science-and-technology perspective. It's written in this glorious 'I was there' sort of tone," says Mindell, who teaches engineering and manu­facturing history and directs the Science, Technology, and Society program.

Digital Apollo, the third of Mindell's books about human-machine interaction, examines the fractious relationship between the Apollo astronauts and engineers--and traces that tension to a debate stretching back to the Wright brothers.

Pilots and aircraft engineers have always understood that planes can be very stable or very responsive, but not both; although modern digital control systems make the trade-off less stark, the more control a pilot has over a craft, the more difficult it is to keep it aloft. As aircraft engineers began to design automated systems to make planes more stable, engineers and test pilots argued over the value of human skill in flight. When the prospect of spaceflight beckoned in the 1950s, test pilots advocated for human control with renewed vigor.

In every aspect of the Apollo missions, Mindell says, astronauts fought to persuade engineers to allow more human control. The astronauts won some ­battles--preserving the option to control lunar landings--but lost others. (Mindell notes that Apollo 7 pilot ­Walter ­Cunningham griped in his memoir about the command module's undignified splashdown landing, with the astronauts fished out of the sea "like a bag of cats saved from a watery grave.")

Informed by flight data, mission transcripts, and engineering records, drawn in many cases from MIT's archives, Mindell's book is a thoughtful complement to the traditional Apollo story--the tale of the astronaut as rugged American individualist, boldly exploring the frontiers of space. But in rewriting the history of the moon landings, Mindell does more than take aim at its heroic mythology. He also distills Apollo's lesson: as our technological prowess grows, the creative process of discovery involves an increasingly complex interplay between human and machine. ­Mindell notes that similar lessons are being learned on other frontiers, from deep-ocean exploration to robot-assisted surgery.

"The book isn't primarily about spaceflight," says Mindell, "but about what it means to be human in the world of computers and intelligent technology."