In 1964, NASA solicited chronographs from American watch distributors to find a watch that could serve as a backup timer on Gemini and Apollo missions. Three wrist chronographs entered the formal trial — Omega’s Speedmaster ref. 105.003, a Rolex ref. 6238, and a Longines-Wittnauer ref. 235T. (A fourth respondent, Hamilton, submitted a pocket watch and was disqualified.) NASA engineer James Ragan ran each watch through eleven environmental tests — heat, cold, vacuum cycling, humidity, pure-oxygen corrosion, shock, acceleration, low and high pressure, vibration, and 130-decibel acoustic noise. Only the Speedmaster finished all eleven, and in March 1965 NASA declared it “Flight Qualified for All Manned Space Missions.” Run the gauntlet the way his lab did: press Run test on each trial, in order, and watch the field narrow.
The field
At Deke Slayton’s instigation, NASA issued a formal solicitation to roughly ten American watch distributors in 1964; four answered. Hamilton disqualified itself by submitting a pocket watch. That left three wrist chronographs for the formal trial: the Omega Speedmaster ST 105.003, the Rolex reference 6238 (the pre-Daytona), and the Longines-Wittnauer 235T.
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 qualified the Speedmaster “Flight Qualified for All Manned Space Missions.” The rest is lunar history.