Just What Do You Think You're Doing, Dave?  How Apollo's
astronauts learned to work with--and around--their computers
Digital Apollo  By David A. Mindell; MIT Press, May 2008; 456
pp.; US $29.95; ISBN: 978-0-262-13497-2  In 1961, the average
rocket-borne computer ran on average for 15 hours before an
electronics ­failure crashed it. That ­dismal ­performance
record didn’t matter much to the ­military, whose suborbital
­missiles required only ­minutes of computer on-time. But a
manned moon shot required that computers run 1500 hours between
failures.  As David Mindell points out in Digital Apollo: Human
and Machine in Spaceflight , NASA’s project managers not only
met that 1500-hour goal but greatly overshot it. When Neil
Armstrong and his compatriots strode on the lunar surface
between 1969 and 1972, the total mean time between ­failures of
the onboard computers turned out to be closer to 50 000 hours.
The story is more than a historical ­footnote. Computer systems
­reliability was perhaps the biggest spin-