Checklist: The Secret Life of Apollo's "Fourth Crewmember"

The story of American human spaceflight offers historians a new opportunity to study the relationships between high technology, elite labor, and the printed word.  During the explorations of Project Apollo, checklists, data cards, flight plans, and navigation aids became what one astronaut called the spacecraft's "fourth crewmember" and, arguably, its real commander.  Even with the arrival of the first lightweight digital electronic computers, the interior of a spacecraft of the 1960s was hardly a paperless office---in fact, it could be a positively 19th-century environment, in which information moved in words and numbers printed in small pamphlets or handwritten on paper cards and notebooks.  Checklists, though, were not meant to be mere training tools or emergency references; rather, astronauts read, discussed, and modified them throughout their journeys.  Just as 19th-century intellectuals consumed the latest tracts on natural science---annotating pages, tearing spines, and making books their own---astronauts labored over inches-thick binders intended to serve as fluid logs of their own achievements, filled with pen and pencil checkmarks, annotations, ruminations, and smutty jokes.  Borrowed from general aviation, checklists proliferated in space; America's astronauts became devotees of the technology, which approximated the mechanical precision of automated systems while enabling humans to remain in control of their vehicles.  Instead of bemoaning checklists as a deskilling intrusion on their autonomy, America's astronauts embraced them as emblematic of the rigorous training and precise control they could bring to the space program.  Apollo astronauts, in turn, flew their spacecraft to the Moon literally with book in hand, creating a personal relationship between crewmember and the written word unseen since the Victorian era.