In 1964, NASA engineer James Ragan needed a chronograph the astronauts could bet their lives on. He bought watches anonymously off the shelf — about $82.50 apiece — and put them through eleven trials designed to break them. Run the gauntlet the way his lab did: press Run test on each trial, in order, and watch the field narrow.
The field
Ragan approached ten manufacturers; four answered. Hamilton disqualified itself by submitting a pocket watch. That left three wrist chronographs, bought at retail so no maker could send a ringer: the Omega Speedmaster ST 105.003, the Rolex reference 6238 (the pre-Daytona), and the Longines-Wittnauer 235T. Each maker sent three watches — one to test, one to fly, one as backup.
What “passing” meant
After every trial, each watch was checked for timekeeping. The standard was brutal and simple: it had to keep running, and keep time, through all eleven. On March 1, 1965, one watch had done exactly that — and NASA certified the Speedmaster “Flight Qualified for All Manned Space Missions.” The rest is lunar history.